California Legal TBI Conversion for a 1980 CJ-7 Jeep

[Bob95064]

I have a question about an article I read on 4WDMechicx.com when researching converting a CJ to TBI.  The article can be found here: https://www.4wdmechanix.com/MSD-Atomic-EFI-for-Jeep-4.2L-Inline-Six?r=1

I have a 1980 CJ-7 with the 258 I6 engine.  It was sold to me non-op and is missing some emissions parts that are hard to find and expensive.  Going in my plan was to convert it to fuel injection to increase reliability, economy and make emissions testing easy.

I found the above article that was very informative and well written.  I dug into the details and have some questions.

The article points to emissions testing in California a few times and I was hopeful that I could also put a MSD Atomic system on my Jeep.  This was appealing to me because I put a MSD billet distributor, 6A spark control and a Blaster 2 coil on the Jeep.  The Atomic system would work hand-in-hand with my ignition system and allow me to program advance curves.

When I dug into the details I found that the Atomic system that was installed was part number 2900.  Here is a direct link:  https://www.holley.com/products/fuel_systems/fuel_injection/atomic_efi/atomic_efi_tbi/parts/2900. This appears to be an older system than the Atomic 2 offerings but is the only fuel injection system sold by MSD or Holley that is California legal.  Scroll down to the Emissions heading and you'll see that is is legal under C.A.R.B. EO #D-722.

I Googled EO D-722 and found this page:. http://ww2.arb.ca.gov/sites/default/files/classic/msprog/aftermkt/devices/eo/d-722.pdf.  In reading the EO I see that the vehicles that this system is authorized for road use in California are GM vehicles made in 1987 and earlier with a V8 engine.  California Executive Orders call out the specific vehicles the subject part can be used on.  For example I have a MSD 8516 billet distributor on my Jeep.  This is the EO for that part:. https://arb.parts/Executive-Order/D-40-39. If you scroll down to Exhibit A it lists 1993 and older AMC inline 6 cylinder engines under the 8516 part number.  The point is the EO lists applications for each EO and if a vehicle is not called out in the EO the part is not legal for use  on that vehicle.

Getting back to the Atomic conversion in the article:. How were you able to pass a visual inspection when the Atomic system in not called out in the EO?  In the past some smog shops would accept a CARB stickered conversion without checking the EO.  I'm not sure that is the case now.  If so putting this system on a Jeep is somewhat of a gamble.  If a smog tech reads the EO the vehicle will fail.  In that case the TBI will need to be replaced with a compliant part.  The cost of the Atomic system is high - too high for me to risk a failing visual inspection.

It seems to me that the only option for a fuel injected conversion on a CJ in California is Howell TBI.  Please let me know if I'm missing something with the Atomic system and CARB legality.  I've researched this for weeks and don't see how it can be legally used on the streets of California when installed on a Jeep with a AMC 258.

Thank  you,

Bob Elliott

[Moses Ludel]

Hi, Bob...To your point, you're absolutely correct.  California E.O. numbers assign use of equipment on specific vehicles.  The Atomic EFI would need approval for use on your specific 4.2L engine.  If you go for a biennial smog inspection, the system's E.O. number would be evaluated for its use on your 4.2L engine.  The CJ would fail that test if the E.O. for the 2900 product does not include approved use on your engine.

You're doing your due diligence here.  Confirm whether the 2900 does or does not meet E.O. exemption status for a 1980 Jeep 4.2L inline six.  If it does not, spend your money elsewhere if you need to smog this Jeep.  The current, cost-effective EFI conversion with a California E.O. for your 4.2L engine would be Howell Engineering's TBI kit.

As a point of interest, the off the shelf parts that make up the Mopar EFI Conversion (MPI) are 1991-95 YJ Wrangler 4.0L for the earlier two-rail kit and a mix of 1995 and '97-up (single rail EFI) TJ Wrangler.  The Mopar Performance kits (early and later) have California E.O. numbers that allow for an emissions inspection and a "pass" if functioning properly.  Despite the fact that you can duplicate the kit with recycled donor parts from a 1991-95 YJ Wrangler or XJ Cherokee does not make the system emissions legal unless you use the E.O. approved Mopar kit ($$$$).  In both cases, the performance improvements and emissions reduction is the same; however, the E.O. approved kit is legal, and the recycled donor parts approach is not.  Making up your own "kit" from recycled parts will guarantee a failed emissions test.  The smog station or referee is looking for the California C.A.R.B. E.O. decal and proof that you have an approved Mopar EFI Conversion Kit.

This is the reason many do V-8 conversions, using the complete LS or whatever engine and its necessary emissions system.  For the cost of a Mopar EFI Conversion Kit, they can follow California guidelines for an engine swap and make the vehicle emissions legal after a visual and tailpipe inspection at an official smog referee station.  If you have the tools to perform this work and access to a recycled engine and its necessary emissions pieces, this could be less headache than restoring the emissions system on an earlier carbureted Jeep 4.2L. 

Here is a recent article I did on California legal engine conversions (pointed at diesels but the same principles apply for a gasoline engine) plus a video on Advance Adapters' California legal LS V-8 swap into a TJ, which would be similar to a CJ/V-8 swap.  Considering the age of your Jeep, you would have the option of using a 1987-up GM 350 TBI iron V-8 small-block, which would be simpler and less emissions ladden.  Any EFI engine would be a tailpipe emissions improvement over a 1980 Jeep 4.2L BBD carbureted engine in its original form:

https://www.4wdmechanix.com/Cummins+4BT+and+4+ISB+Diesel+Engine+Conversions

https://www.4wdmechanix.com/HD-Video-Advance-Adapters-Jeep-TJ-Wrangler-LS-V-8-Conversion?r=1

Have you looked into the actual parts you need to restore the 4.2L emissions system?  I have some new, in-the-box OEM Mopar pieces from that era that have been in storage.  I'm willing to sell these pieces at this point, as restoring 4.2L engines is not in my future.  In particular, I have a new catalytic converter and the rare heat tube that fits between the manifolds.  I don't have any of the parts needed if your engine and chassis have the wholesale "de-horning" or stripping of modules and solenoid pieces, the "Nutter Bypass" stripping/conversion or whatever. 

What are you missing?  We can discuss whether you have a way to go with restoring the OEM emissions system.  Of course, the net result would be 1980 performance, poor fuel mileage and the inhibitions created by heavy emissions tuning.  Frankly, I'm biased, but our needs these days include fuel efficiency and a clean tailpipe.  I'm drawn to EFI factory engines for their fuel efficiency and cleaner tailpipe.  Many CJ owners have turned to 4.0L "donor engine" swaps, using 1991-95 4.0L engines.  A 1991-95 complete engine package (MPI, computer, harness and exhaust header included) from a recycled XJ Cherokee or YJ Wrangler has become popular and can pass emissions if the conversion is done properly.

Moses

 

[Bob95064]

Thanks for your reply and confirming my research.  FYI you may want to amend your article to say that the Atomic conversion is not CA legal.  If someone were to spend the money for an Atomic TBI based on your article and fail smog you may get a nasty email from a very upset reader.

I agree with you that fuel injection is the way to go with a CJ.  I also came to the same conclusion about a "junkyard" Mopar EFI conversion.  I could do it for a fraction of the cost and have the same thing as the expensive kit and don't pass smog.  Really if Califonia was really concerned about pollution they would test an older vehicle and if the emissions were below a set limit it would pass no matter what was under the hood.  I think the reality is money is motivating CARB more than pollution.

My Jeep has a Chinese BBD clone and the two thermal switches in the air cleaner housing don't work.  These are NLA and when you do find them they are extremely expensive.  The preheater hose and exhaust manifold shroud are missing.  The wiring is a mess and all the old ignition wires are gone.  This is a moot point because I put an MSD ignition on it which was a huge upgrade.

I plan on going the Howell route for reliability and economy.  Really after reading on both the Howell and MSD systems I came to the conclusion that in some ways I'm better off with the Howell.  Parts are available for the Howell system nationwide because it consists of GM parts.  This is a big advantage if something happens while on a trip.  It runs at a low fuel pressure so leaks are less likely.  The downside is it is 20+ year old technology.  The MSD system is programmable and would offer spark control for my MSD ignition.  It's really not an option if you live in CA.

When I started this journey of getting back into Jeeps after a 25+ year absence I thought about getting a pre 1998 model and swapping a 4BT Cummins diesel into it.  I have a 1997 Ddge Ram with a Cummins that I live so another Cummins seemed like a good idea to me.  I called the CA smog referee two times and was told that swapping a diesel into a Jeep would not be approved.  They said CARB won't accept making a vehicle that requires smog checks to be smog exempt.  They also said California is trying to phase out diesels altogether.  Very, very sad.

I bought the 1980 CJ-7 because it was a great base for a project, someone had swapped Dana 44s front and rear and I got a pretty good deal because the seller didn't know how to unravel the electrical priblems.  I'm glad to have it.

I had a 1979 CJ-4 that I bought in 1994 when I lived in the Midwest.  It was a victim of road salt and needed a full restoration.  I bought your Jeep Owners Bible in 1994 and still have it.  Thank you for many years of sharing of knowledge on these fun vehicles.

I go up your way on off-road trips a few times a year.  I live the deserts east of Reno and have logged many hours on trails in 4Lo.  We also go to Sourthern California often.  There is so much fun to be had in the deserts of the west.

[Moses Ludel]

Hi, Bob...As per your concern about amending the article(s), I took your cue.  Thanks for raising this concern...The article format at the magazine was a five-part series plus an interview video with Dan Hiney.  In several of the original segments, I clearly indicated that the MSD Atomic EFI does not have a California E.O. number.  In "Part 2" (https://www.4wdmechanix.com/MSD-Atomic-EFI-for-Jeep-4.2L-Inline-Six-2?r=1, titled "History of OEM EFI and Aftermarket Kits for the Jeep 4.2L Inline Six", I devoted an entire section to emission legality and what buyers need to know about Atomic EFI and other kits.  One section of the series had this statement:

"*Note: As of summer 2012, the new MSD Atomic EFI does not carry a California E.O. number for the Jeep 4.2L inline sixes. We're encouraging MSD to pursue a California E.O. number for this Jeep application and will update. Although Dan's Jeep meets/exceeds the standards for this vehicle, an E.O. number is necessary for California emissions compliance."

A few of the article sections did not make concise emission legality statements.  I assumed viewer/readers would read through the entire series.  As you experienced, if not read as a series, a search could land on a section without E.O. comments and perhaps lead to considering Atomic EFI despite its lack of a California E.O. number. 

I encouraged MSD to pursue an E.O. number.  The company assured Dan Hiney and me that it was doing so.  (Dan lives at California.  Tragically, his family's Magalia home burned to the ground in the Paradise fire.  He had no tools or place to work on the Jeep and sold it.)  As you discovered, the Jeep 4.2L was not important enough for MSD's market focus.  The company went through a financial crisis and eventually ended up in the Holley consortium.

To help viewers and follow-up on your helpful suggestion, I have added a clear "Caution" at each section of the series.  There are two lead-in caution statements, depending upon the section's content.  My point is clear:

"Caution:  If your vehicle must comply with emission regulations or inspections, confirm the emission legality of this Atomic EFI system for your specific vehicle and engine type before installing Atomic EFI.  Review the manufacturer's literature.  If you intend to register/license your Jeep for use in California, any EFI conversion kit or aftermarket carburetor must have a Clean Air Resources Board (CARB) Executive Order exemption number that approves the product's use for your specific vehicle and engine type.  Other states now have similar regulations.  Check with state and local requirements before purchasing the MSD Atomic EFI kit."

and

"Caution:  If your vehicle must comply with emission regulations or inspections, confirm the emission legality of any EFI conversion or aftermarket carburetor.  If considering a kit like MSD Atomic EFI, California and many other states require equipment approval for your specific vehicle and engine type.  Review the manufacturer's literature.  If you intend to register/license your Jeep for use in California, any EFI conversion kit or aftermarket carburetor must have a Clean Air Resources Board (CARB) Executive Order exemption number that approves the product's use for your specific vehicle and engine type.  Other states have adopted similar regulations.  Check with state and local requirements before purchasing any EFI conversion kit or retrofit aftermarket carburetor."

So, back to your 4.2L 1980 engine.  For years, many states had a tailpipe reading inspection only, without the visual inspection that California requires.  Arizona did that then capitulated, adopting the California model as did Nevada.  The lines get blurred around compliance with EPA certification and the OEM equipment described on the underhood decals.  California's ARB, being a committed bureaucracy, became the 50-State gold standard for rule oriented emissions standards.  Never mind practicality, if a vehicle came equipped with specific, EPA approved equipment when new, that was the ironclad standard for the vehicle. 

As I share in the more recent engine swap article on Cummins R2.8L and 4BT/ISB diesels, the EPA wholeheartedly supports California's standards.  California essentially enforces the OEM benchmarks set for motor vehicles.  If there is a "payoff" for CARB, it would be a huge, institutionalized California bureaucracy with many, many employees and managers who are each making their way toward a healthy retirement.  Clean air is the commodity, and independently owned and operated smog stations (a California trade-off when selling the smog program in the eighties) must buy expensive equipment.  The cost is passed to consumers who comply with mandated inspections or cannot operate their vehicles.  It's an industry.

Even an engine swap must follow the certified EPA/California standards for the donor engine.  This includes many chassis (exhaust system in particular) pieces in addition to the engine assembly with all of its original emissions controls and features intact.  California wants that engine assembly to be the same emissions class as your vehicle chassis, and the engine must be either the same year as or newer than your chassis.  The tailpipe emissions must be the same or lower than the acceptable limit for your vehicle's original engine in good operating condition.

Fully agree on the Howell system, which is the smartest and most user friendly approach you can make—especially with the electrical mess and OEM missing parts.  Your existing MSD ignition upgrades, if E.O.-approved, can be used.  (You will find my original discussion of Howell EFI in the Part 2 segment on EFI history.)  Bill Howell was a GM engineer and relied on proven, off-the-shelf parts for most of the system.  Better to visit a local parts house on a Sunday for common GM TBI parts than to be stuck at Jarbidge, Nevada with failed, proprietary MSD Atomic EFI parts.

When you have time to read the diesel engine swap article at the magazine, you'll see similar conclusions about avoiding the diesel swap.  It's not emission legal.  Even the R2.8L is not California approved.  Cummins initially tried to approve the engine in crate form.  I was on board with Advance Adapters to do the R2.8L swap into my XJ Cherokee, but I knew a blanket "crate engine" approval would be difficult.  Cummins tried to earn an E.O. number while the VW diesel debacle was front and center.  I have been involved with CARB and smog requirements since the mid-eighties and discussed CARB expectations with Cummins.  I explained that without an EPA certified prototype vehicle (like the Cummins R2.8L/Nissan Frontier concept vehicle, which unfortunately never went into production), they would not get approval.  GM certifies crate motors on the basis of a given Chevrolet chassis application that has already gone through EPA certification.  No vehicle prototype, no EPA certification. 

Cummins didn't listen to me (corporate bureaucracy, not much different than state bureaucracies) and continued to pursue an E.O. number as a crate motor.  The company is still without a California E.O. number for the R2.8L diesel despite the fact that this engine is clean burning and passes 1999-back EPA recognized emissions Tiers.  (See the R2.8L emissions statement at https://www.cummins.com/engines/repower.) 

I'm pleased that you find our Nevada high desert country fun.  High Rock Canyon and the Central and NE Nevada remote country are my favorites.  As you know from my books (thanks for the kudos), I am an Eastern Sierra fan, too.

Let us know what you wind up doing.  Frankly, a 4.0L swap with EFI, with or without adding a 4.6L stroker crankshaft, would pass emissions.  This would be a legal engine swap with all of the engine's emissions and necessary exhaust pieces in place.  Off-the-shelf parts, etc., an alternative to Howell, the 1991-95 donor engines are readily available.  You need the wiring harness from the donor vehicle and some time to sort out the chassis/engine wiring.  If the current 4.2L engine is sound and you like its performance and torque profile, Howell would be my EFI choice given today's pricing for the expensive Mopar Performance EFI/MPI Conversion Kit.

Moses

[Bob95064]

Thank you for your reply.  Sadly many manufacturers seem to not be interested in dealing with jumping through the hoops that California has imposed to make aftermarket mods legal in the Golden State.  I plan on driving this Jeep on the road so I'll go with products that comply.

I agree with your assessment of the CA emissions laws.  I see the same thing in the planning department in our county.  It is a large bureaucracy with layers of laws that seem to be in place to generate revenue to keep people employed.  Obtaining a permit is a emotionally and financially painful process.  I question what good all the regulations do.  I have a friend that moved from Santa Cruz, CA to Gardnerville, NV.  He erected a very large prefabricated steel building that he uses as a shop.  I asked him about the permitting process.  He said he walked in to the planning department expecting a long, expensive fight.  He said he walked out after an hour with a permit that cost him $150.  In Santa Cruz that would have taken a minimum of 2 years and at least $20k before breaking ground. 

Getting back to emissions it is a sad state of affairs that many parts of the country are using CA as the "gold standard" for emissions testing.  Like I said before if emissions were really the concern a smog test would consist of a tailpipe test and that is it.  The concern shouldn't be what is under the hood but what comes out the tailpipe.  I have a friend that bought a 1977 CJ-7 in Denver.  The emissions test was a tailpipe test and a tailpipe test alone.  They didn't even open the hood.  That is how it should be.

I plan on keeping the stock 258 and modernizing it.  I like the idea of keeping the original engine and I like the torque it develops.  Fuel injection will increase power, torque, mileage, reliability and make smog checks easy.  It's a no-brainer in my book.  This is also a mod that is easily reversible although I can't think of a reason to go back to the BBD carburetor.  Like I said the only way to do this legally in California is to go with a Howell kit so that's what I plan to do.

The 1980's are a time in automotive history that wasn't very good.  The building EPA laws combined with underdeveloped technology made engine compartments that were packed with emissions components that weren't very good or reliable.  I am thankful to have found a 1980 model year CJ-7 and not one later in the 1980's.  I see the increased complexity under the hood year after year and I don't want any part of it.

The drivetrain is what sold me on this CJ.  It has the 258, a T-18 transmission, a Dana 300 transfer case that has been twin-sticked and Dana 44s front and rear.  The PO recently replaced the alternator, starter, starter solenoid and put on a brand new Chinese carburetor and steel fuel tank.  It needs work but is a pretty solid base for a project.  It came with 33" mud tires but has 3.73 gears.  4.10s would be better especially with the 1st gear that doesn't have a synchro.  Lower gears are on the list for future upgrades.  I guess they say a Jeep CJ is never done...

I have a question about the MSD ignition but first I'll go through some background.  I bought the three components used.  It turns out I made an error when I told you what I had.  The box is a 6 Offroad model (6470) not a 6A.  I realize these have a reputation for being unreliable but this one works for the time being and I got the package for less than 1/2 the cost of the distributor alone.  If the 6470 goes out I'll buy a new 6 or 6A box and still come out way ahead.

Anyway, the PO had the MSD ignition in a CJ-8 that he is now doing a frame-off restoration on.  He decided to abandon the 258 and go with a 4.0 swap so he was selling parts off the 258.  Again, I have the Offroad box, a Blaster 2 coil and a 8516 pro billet distributor.  Here is the question:  The PO had the vacuum advance on the distributor locked out and removed.  He said he used the mechanical advance alone and felt that using both mechanical and vacuum advance was too much.  I'm afraid that I won't pass a visual inspection when I get is smogged without the vacuum advance connected.  Have you heard of anyone doing this before?  I wonder if he used the wrong springs for the mechanical advance and using both mecahnicl and vacuum advance caused the timing to advance too much.  If that is true I could remedy the problem by installing the vacuum advance, removing the lockout screw and installing stiffer springs on the mechanical advance weights.  MSD sells a spring and bushing kit:  https://www.holley.com/products/ignition/distributors/distributor_accessories/distributor_components/parts/8464 and a vacuum advance kit:  https://www.holley.com/products/ignition/distributors/distributor_accessories/distributor_components/parts/8463  I asked the PO about these parts and he threw them away :(.

I have a couple other questions I'll post here but expected to get answered by MSD/Howell.  First, the GM ECU needs a tach signal to function properly.  Do you know which tach adapter I need to put between the MSD box and the GM ECU?  Also will this tach adapter work with an AMC tach?  I don't have a tach yet but am looking for one.  

Second, is there a way to setup a Howell TBI system and MSD ignition so that the GM ECU controls the spark advance?  I would think this would increase efficiency.  If that is an option I would like to take advantage of it.

Thank you for reading my posts and taking the time to reply to them.  I enjoy the technical discussion and appreciate your sharing knowledge.  I am a mechanical engineer who was educated in the Midwest.  My degree was pointed at automotive engineering but I don't work in that industry.   Instead I settle for being a weekend mechanic and that is fine with me.  I'm happiest when my hands are greasy and I have an engine disassembled for repair.

I live in the mountains above Santa Cruz, CA so I have to drive to the desert.  I'm not complaining - living in the redwood forest 10 minutes from the beach is a dream come true.  Our group drives a long way to get to the desert but we are equidistant from northern Nevada and the Mojave Desert.  e usually go out in a group of 2 to 10 friends when we overland in the desert.  We have followed the Applegate-Lassen trail from Rye Patch Reservoir to 34 north of Gerlach many times.  It is one of my favorite trips for the scenery and history.  Desert 4x4 exploration is a very unique experience that is one of the things I enjoy doing most.

I enjoy researching an area then exploring historical sites in those areas.  The 7 Troughs Mining District was a fun place to explore.  We found evidence of the flash-flood at Mazuma, NV in 1912.  Have you been to that area?  The 4x4 trails aren't that challenging but the history and scenery is worth the trip.

Thanks for the enjoyable dialog and knowledge,

Bob Elliott

[Moses Ludel]

10 hours ago, Bob95064 said:

Answers to some of your questions, Bob:

Here is the question:  The PO had the vacuum advance on the distributor locked out and removed.  He said he used the mechanical advance alone and felt that using both mechanical and vacuum advance was too much.  I'm afraid that I won't pass a visual inspection when I get is smogged without the vacuum advance connected.  Have you heard of anyone doing this before?  I wonder if he used the wrong springs for the mechanical advance and using both mecahnicl and vacuum advance caused the timing to advance too much.  If that is true I could remedy the problem by installing the vacuum advance, removing the lockout screw and installing stiffer springs on the mechanical advance weights.  MSD sells a spring and bushing kit:  https://www.holley.com/products/ignition/distributors/distributor_accessories/distributor_components/parts/8464 and a vacuum advance kit:  https://www.holley.com/products/ignition/distributors/distributor_accessories/distributor_components/parts/8463  I asked the PO about these parts and he threw them away :(.

Depending upon the Howell installation instructions, you may be required to run both vacuum and centrifugal advance.  Does this MSD distributor have an E.O. number?  "Off-Road" is ominous language with the aftermarket...If it has an E.O. with the vacuum and centrifugal advances operative, you must hook up the vacuum canister and a vacuum source hose from ported (not manifold) vacuum at the TBI unit.

I am a strong advocate of using a vacuum advance unit if the Howell TBI is intended to work with one.  Ported vacuum advance is strictly for throttle tip-in and lower throttle valve opening, which will improve engine response at off-idle and these low throttle positions (i.e. trail running or low range crawls).  Yes, you will likely need to restore the vacuum and centrifugal advance spark timing curves, bringing them somewhat closer to the 4.2L Motorcraft OEM distributor curves or at least MSD's base or milder performance settings.  A CARB Referee Station or Smog Check site would at least be interested (arbitrary) around the base timing setting.

I have a couple other questions I'll post here but expected to get answered by MSD/Howell.  First, the GM ECU needs a tach signal to function properly.  Do you know which tach adapter I need to put between the MSD box and the GM ECU?  Also will this tach adapter work with an AMC tach?  I don't have a tach yet but am looking for one.

We did need an MSD tach interface device for running the MSD system with the Atomic EFI and a stock Wrangler tach.  (See the Atomic EFI series at the magazine, I discuss that device.)  Every MSD ignition I've installed on a Jeep application has required an MSD interface tach device;  however, for your application, this is a question that MSD (Holley) or Howell can answer best.   

Second, is there a way to setup a Howell TBI system and MSD ignition so that the GM ECU controls the spark advance?  I would think this would increase efficiency.  If that is an option I would like to take advantage of it.

To my knowledge, the Howell TBI does not have an ignition component in the ECU.  Whether the ECU can be programmed to produce a spark signal is another story that Howell can answer.  Howell TBI installations work independently of the ignition, which has allowed use of the Motorcraft OEM distributors or an E.O. approved aftermarket distributor.  I know where you're going with this.  Yes, Howell TBI is an O2 feedback TBI-based fuel supply system and not a true engine fuel and spark management system.  Whether it can be used with interactive spark management software like a GM 4.3L V-6 ECU/ECM is the question.  The TBI unit and other parts are prototype 4.3L pieces as near as I can tell.  

The question would be getting a 4.2L Jeep distributor (either OEM or aftermarket) to function as part of an ECU/ECM driven fuel and spark delivery/advance system.  You could "build" a distributor upper section with GM EFI era components, add a knock sensor, etc.  However, since there's no means for emissions C.A.R.B. E.O. approval, the Referee or Smog Check station could fail the hybrid system.  This is assuming the station cares.  Howell TBI with an E.O. usually is a quick pass at the station, as the basic system is E.O. approved around the TBI, ECU, O2 feedback and the tailpipe readings—which are always a major improvement over CJ/BBD 4.2L tailpipe readings.  You'll find out. 

Downloading a copy of the Howell TBI installation instructions would demystify some of these concerns and clarify others.  The distributor gets casual mention, as this is not a component of the Howell system.

Thank you for reading my posts and taking the time to reply to them.  I enjoy the technical discussion and appreciate your sharing knowledge.  I am a mechanical engineer who was educated in the Midwest.  My degree was pointed at automotive engineering but I don't work in that industry.   Instead I settle for being a weekend mechanic and that is fine with me.  I'm happiest when my hands are greasy and I have an engine disassembled for repair.

I live in the mountains above Santa Cruz, CA so I have to drive to the desert.  I'm not complaining - living in the redwood forest 10 minutes from the beach is a dream come true.  Our group drives a long way to get to the desert but we are equidistant from northern Nevada and the Mojave Desert.  e usually go out in a group of 2 to 10 friends when we overland in the desert.  We have followed the Applegate-Lassen trail from Rye Patch Reservoir to 34 north of Gerlach many times.  It is one of my favorite trips for the scenery and history.  Desert 4x4 exploration is a very unique experience that is one of the things I enjoy doing most.

We live relatively close to Gerlach and enjoy High Rock Canyon when the Burning Man is not in session on the Playa.  I've done some video and articles on High Rock and the wagon route.  Usually a long day trip, we usually come out on 34 and wind up at Bruno's in Gerlach for a quasi-Italian dinner.  My wife is of Italian ancestry, so few Italian dinners meet her standard, but Bruno's certainly serves as an "Old Nevada" restaurant. 

Before heading for the University of Oregon, I ran heavy equipment out of Local 3, Operating Engineers, Reno, including jobs like the I-80 bypass of Winnemucca in the mid-seventies.  I also know Central Nevada and Elko County.  My Northern Nevada backcountry experience dates to the sixties, I graduated from Douglas County High School at Gardnerville, a class of 49 students, in 1967.  Nevada's mining history, indigenous prehistory, precious water and land forms have been a part of our family's outdoor life and culture.

I enjoy researching an area then exploring historical sites in those areas.  The 7 Troughs Mining District was a fun place to explore.  We found evidence of the flash-flood at Mazuma, NV in 1912.  Have you been to that area?  The 4x4 trails aren't that challenging but the history and scenery is worth the trip.

The neighbor across the street hunts at 7 Troughs as does one of my brothers-in-law.  If you need information on that area, I can furnish details of what remains.

You'll be very pleased with the simplicity and troubleshooting ease of the Howell TBI.  Any OEM or E.O.-approved distributor would work.  Howell may have some recommendations on spark curves (centrifugal and vacuum) that work well with a "standalone" Howell TBI system.

Moses

[Mike S]

Hello, first off, I just want to say thank you for thread. It has been very informative. Next, I'd like to ask has anything changed in the couple of years since this thread was written? By this I mean, have any other companies/manufactures come on boards with a C.A.R.B. compliant TBI system for the 80's AMC/Jeep 258?

I live in a county in Nevada that requires a smog inspection to register your vehicle. While there are some legal ways around this, they limit you to the miles that you can drive your vehicle and also require you to carry special insurance.

I am currently building a 1981 Jeep CJ8 Scrambler. It came from the factory as a "California Emissions Vehicle" with the air pump, solenoids mounted to the firewall, 10 miles of vacuum hoses, etc. I'm building this to be a daily driver and a capable off roader, so I definitely want to convert it to a TBI system for reliability and performance. As Bob95064 stated above, I really like the idea of keeping the original engine and adding the modern upgrades.

I have searched the internet and found a couple of other options for TBI kits for this application other than Howell. They appear to have the same components as the Howell kits and in one case, is half the price. I spoke with the company that offers the kit for half the price to see if they knew if their kit would be legal in my county, they told me to contact the DMV for the requirements. I then spoke with the DMV and even showed them the other kit compared to the Howell kit. While the DMV agreed that the kits were nearly identical, they basically told me that because this kit didn't have the C.A.R.B. compliance sticker that stated "it was ok to remove the air pump' that it would not pass their inspection.

My question is for Moses Ludel (because it appears in your avatar that you may live in the same county as me), are there any other options for a TBI kit or any other "legal" work arounds (for lack of better words) that you may be aware of? I am on a fairly tight budget as it is in the Restomod of this project and anywhere that I can save money, will definitely help me get this thing on the road sooner.

Also, can I use an HEI distributor with a TBI kit?

Thank you in advance any help that you can provide,

Mike S.

[Moses Ludel]

Mike S...Howell TBI has been the historic go-to solution.  Howell received a California E.O. Number decades ago.  At that time, the Mopar MPI/EFI Conversion was the only 50-State legal system and somewhat affordable.  The Mopar system is patterned after the 1994-95 Wrangler YJ 4.0L components.  Howell's conversion is built around 4.3L GM V-6 components.

In 2015, we experimented with MSD Atomic EFI on a YJ Wrangler 4.2L engine.  (See https://4wdmechanix.com/?s=MSD+atomic for links to all the details on our 4.2L installation.)  The system worked and tested well on the Rubicon Trail.  Since then, MSD has received an E.O. number for Atomic EFI retrofit on 1987 and older GM V-8 engines.  No Jeep 4.2L kit on the horizon.  There is simply not enough demand or volume, and the Atomic EFI unit is better suited for V-8 displacement engines.  The system retails for over $1500.

The Mopar EFI Conversion is no longer an option.  Some owners use kit components from HESCO and install donor 4.0L MPI systems on their 4.2L.  Some install the entire 4.0L cylinder head with it, which requires minor modifications to coolant ports in the 4.0L head.  However, you'd run into exactly the same dilemma you currently face:  No California E.O. number for the donor parts.  Holley (parent company for MSD now) has its own TBI units available and legal as OEM replacement for factory TBI GM V-8s and 4.3L V-6s.  This is a CARB E.O. legal replacement product but not legal for your 4.2L Jeep engine.  (It would not have the peripheral parts, either, like the ECM, wiring, sensors, etc.)  The units for the 4.3L V-6 would likely serve well on a 4.2L Jeep.  That, essentially, is what Howell has offered, a GM 4.3L TBI unit supported with GM peripheral parts and a wiring harness.  You would need Howell's CARB E.O. compliant kit.

Other than registering your Jeep outside Washoe or Clark County, which I would not do or recommend, it looks like Howell is your answer for a 50-State legal, California approved, Jeep 4.2L TBI conversion that would be smog legal at Washoe County....To clarify, we're at Fernley (Lyon County) and don't have inspection requirements.  I still maintain emission legal vehicles.  I had access to a clean burning new R2.8L Cummins diesel crate engine for our '99 XJ Cherokee but passed on the project because it would not be 50-State compliant or legal in the State of California, Washoe/Reno/Sparks or Las Vegas/Clark County.  To date Cummins has not been granted a CARB E.O. number for that engine.  No vehicle has been produced with the R2.8L turbodiesel engine, so there is no EPA or California certification or emissions compliance.  Sound familiar?

Historically, you could run an HEI distributor with a Howell system, or an O.E.M. Motorcraft system can be stripped to the bare distributor without the gaggle of emissions related parts you describe.  (I ran a reliable 5-pin Chrysler module and Ford big-rotor with spacer on the AMC/Jeep Motorcraft distributors.  I describe that in my Jeep Owner's Bible.)  Acceptable distributor type(s) can be readily confirmed by Howell tech support if you go down that road.  An HEI distributor is a simpler, one-wire solution.  Make sure it's a Jeep 4.2L retrofit.

If your Scrambler were not such a cult/collectible, I'd suggest installing a Chevrolet LS V8 engine with the cats and other components that must come from the donor vehicle.  (For details, there's an article at the magazine on Advance Adapters' 50-State legal LS swap into their TJ Wrangler.)  You could swap engines for nearly the same cost as an EFI or even a Howell TBI conversion.  Our next door neighbor sold a pristine, essentially stock 1981 Scrambler a month ago for $18,000.  It had been registered at Winnemucca and sold to a Texas party.  When I glanced at the 4.2L, it looked "dehorned" like your engine.  Very common.

Howell TBI works with your stock intake manifold (BBD style) and would be the easiest and least involved path to EFI.  The engines run well and delivers far better fuel efficiency, power and high altitude performance with the O2 closed-loop system.  It's essentially 4.3L GM V-6 TBI with mostly off-the-shelf GM parts, available when you're stranded at Jarbidge or Austin.

In wrapping this up, you do have one additional option to consider.  Discuss with the DMV or smog inspectors whether you can install a complete 1991-95 Jeep Wrangler or XJ Cherokee 4.0L engine with MPI/EFI from a donor/recycled Jeep.  You would need a complete engine with all peripherals, the 60-way original PCM, the engine wiring harness, all sensors, the exhaust manifold and a legal air intake system.  The 4.0L block will bolt in place of your 4.2L with minor modifications to one engine bracket.  There would be no impact to your frame or the overall structure and appearance of the CJ-8 Scrambler.  The 4.2L spacer/shim, bellhousing and flywheel will work as well. 

You would need a HESCO crankshaft damper for the 4.0L short snout crankshaft/serpentine belt drive and a HESCO crankshaft position sensor that mounts at the oil pan/front of the engine.  (Your 4.2L bellhousing has no provision for a crankshaft position sensor.)  You need the correct crankshaft pilot bearing, simple...In the end, this would be a later 4.0L Jeep engine conversion into your 1981 CJ, which California would allow.  So should Washoe County, Nevada...Without any fanfare, a 4.6L stroker build-up would not impact the appearance of the engine, and it should still pass a tailpipe emissions test.

Moses

[Mike S]

Moses, thank you so much for your reply. Also, thank you for being so thorough with the information that you provide.

I was really hoping for an inexpensive TBI kit that would be legal in Washoe County, mainly because (as I stated before) I am on a very tight budget, and I was hoping to get away with using the factory engine for the time being. The engine seems to run well and appears to have low miles. While I have not driven the Jeep on the street or for that matter haven't driven it any further then around the block. Once I get this Jeep Road worthy, I can determine whether or not I need to do anything with the engine.

I have had a few Jeep CJ's with the 258 but they have all been carbureted (and wouldn't pass smog). I really liked the way performed for my needs both on and off road. So, to keep the 258 in the Scrambler with some modern upgrades would be ideal. The problem is that I don't know anything about the engine and don't know how reliable it's going to be, so I really don't want to invest in an expensive set up for it because if it doesn't work out, I'll probably do a complete engine and transmission swap. I am kind of a purest and would prefer to keep it original with minimal up grades. I'm also rational enough to know if I need to spend the money that I should do it right.

I know that I could rebuild the factory engine and buy the Howell kit but in reality, that would probably be more costly and time consuming than the engine swap. I have upgraded the axles to Wide Trac with the Dana 44 rear and 4:56 gears so I'm not completely opposed to modifications.

While I am a huge fan of the LS motor, I just think it takes too much away from the "Jeep" that the Scrambler represents.

I have definitely considered the 4.0 swap and now that will probably be the route that I take. I'm sure that I could do this swap for around the same price that Howell is asking for their kit. The 4.0's are a dime a dozen and a good low miles engine would be easy to refresh. 

While we're on the subject of the 4.0, can you tell me some of the goods and bads of the automatic transmissions that were used behind these motors over the years? I would really like to have an automatic with an overdrive that would bolt to the 4.0 without adaptors. I don't know much about the automatic that Jeep used but I have owned a few XJ's and a ZJ and never had any issues with the transmission.

I should add that I will on occasion be pulling a little Bantam T3-C trailer with a rooftop tent and a camp kitchen set-up. It's not real heavy but it might make a difference as to which transmission to use.

I know that I'm asking a lot, and after reading some of your other threads, I look forward to any advice that you can give.

 

Thank for your Knowledge,

Mike S.

[Moses Ludel]

Hi, Mike...I'll highlight my replies to some of your concerns below...Moses

On 12/9/2023 at 9:10 AM, Mike S said:

Moses, thank you so much for your reply. Also, thank you for being so thorough with the information that you provide.

You're welcome, Mike...

I was really hoping for an inexpensive TBI kit that would be legal in Washoe County, mainly because (as I stated before) I am on a very tight budget, and I was hoping to get away with using the factory engine for the time being. The engine seems to run well and appears to have low miles. While I have not driven the Jeep on the street or for that matter haven't driven it any further then around the block. Once I get this Jeep Road worthy, I can determine whether or not I need to do anything with the engine.

What does the DMV want you to do in order to make the 258 smog legal?  What do they want to see in a visual inspection?  What pieces would you need to make the 258 legal?

I have had a few Jeep CJ's with the 258 but they have all been carbureted (and wouldn't pass smog). I really liked the way performed for my needs both on and off road. So, to keep the 258 in the Scrambler with some modern upgrades would be ideal. The problem is that I don't know anything about the engine and don't know how reliable it's going to be, so I really don't want to invest in an expensive set up for it because if it doesn't work out, I'll probably do a complete engine and transmission swap. I am kind of a purest and would prefer to keep it original with minimal up grades. I'm also rational enough to know if I need to spend the money that I should do it right.

With care, we can do engine swaps that have zero impact on the frame or engine bay.  With planning and the right mounts, you can swap in a V8 without marring or scarring the CJ if that's your aim or a practical option.  Your OEM motor mounts and frame brackets are bolt-in.  Replacement mounts can be made to fit just like the factory frame bracket mounts.  The original brackets and the 258 engine and radiator could be set aside as a "purist" option for your use later or for resale to a next buyer.

I know that I could rebuild the factory engine and buy the Howell kit but in reality, that would probably be more costly and time consuming than the engine swap. I have upgraded the axles to Wide Trac with the Dana 44 rear and 4:56 gears so I'm not completely opposed to modifications.

That's why I suggest the LS or even an older 350 TBI V8 swap.  Owners struggle to keep a 258 at great cost in both labor and a legal aftermarket EFI system.  When the last Mopar MPI conversion kits were selling for $3000 or more, they lost me.  This is payment for a California E.O. decal, the system is made up largely from OEM 4.0L XJ/YJ parts.  The system gave a 258 approximately 50 additional horsepower over the BBD carburetor and arguably some fuel mileage.  Considering the last 258s were 116 horsepower, that isn't earthshaking.  A stock 4.8L or 5.3L LS V8 motor (get an iron block version) is dirt cheap and will run circles around the EFI 258 in both performance and fuel efficiency.  The 258 was a terrific 1971 upgrade over the 232 for carbureted light Jeep and I-H trucks and CJs.  I was a fleet truck and 4x4 mechanic in those years and revered the seven-main bearing sixes with modest emission controls.  That ship sailed.  By 1981, the overburden of emission controls and BBD induction sapped the 258 of most virtues...Today, I would do the LS V8 swap, choosing the easiest model year version to swap.  In stock form, these engines produce far less emissions than a 1981 carbureted 258 six.  The DMV likes that fact.

While I am a huge fan of the LS motor, I just think it takes too much away from the "Jeep" that the Scrambler represents.

I have definitely considered the 4.0 swap and now that will probably be the route that I take. I'm sure that I could do this swap for around the same price that Howell is asking for their kit. The 4.0's are a dime a dozen and a good low miles engine would be easy to refresh.

This at least "looks" like the 4.2L.  Better yet, your 258 crank and rods could boost a 4.0L to a 4.6L stroker if you decide to exercise that option.  Externally, this all looks like a 4.0L and should pass smog with a stock camshaft (or very mild aftermarket cam) and injectors.  It will pass the visual as a straightforward 4.0L engine swap.  Frankly, Mopar MPI is more efficient than a 258 BBD intake manifold with Howell TBI.  If you do a 4.0L swap, you need to follow the DMV rules for a 1991-95 YJ/XJ 4.0L engine swap, including exhaust system and peripheral items they want to see in place.

While we're on the subject of the 4.0, can you tell me some of the goods and bads of the automatic transmissions that were used behind these motors over the years? I would really like to have an automatic with an overdrive that would bolt to the 4.0 without adaptors. I don't know much about the automatic that Jeep used but I have owned a few XJ's and a ZJ and never had any issues with the transmission.

For a 4.0L overdrive, the XJ Cherokee AW4 is actually a good transmission with simpler cable TV linkage.  The later 42RLE is great but would require considerable interface work for the electronic shift controls.  I would do the AW4 and configure TV linkage via a donor XJ approach.  The AW4 would provide a converter housing with the opening for an OEM 4.0L crankshaft position sensor, too.  Essentially, you would be using the complete XJ Cherokee 4.0L/AW4 powertrain, cables and peripheral pieces from a donor vehicle.  Again, the easiest cohort for this conversion is 1991-95 4.0L 4x4 prototype.  This would be emission legal as a "newer" than 1981 engine for the swap.  The tailpipe emissions will be substantially cleaner than a 4.2L/258 carbureted engine.  The issue here is keeping your Dana 300 transfer case.  You need to mate the AW4 to the Dana 300 with the correct clock position and splining.  Discuss this with Advance Adapters' tech support, they are very familiar with your options here.

If you opt for an LS V8 or even a 350 TBI swap, you have the option of a 700R4 or 4L60E transmission.  Either would be plenty for your plans.  You need a 4x4 transmission application.  Discuss  the Dana 300 adaptation with Advance Adapters tech support.  You will be keeping your Dana 300 for front axle/driveshaft positioning.

I should add that I will on occasion be pulling a little Bantam T3-C trailer with a rooftop tent and a camp kitchen set-up. It's not real heavy but it might make a difference as to which transmission to use.

You would find the weight of your CJ and the trailer to be in the ballpark for AW4 reliability.  AMC used the Chrysler 904 and 999 in the CJs, it's on par or slightly more rugged than an AW4 but does not have overdrive.  AW4s seem to last "forever" in the XJ Cherokee or a six-cylinder ZJ.  My XJ has 192K miles and no rebuild yet.  It's weighed 3,800 pounds curb weight with accessories/wheels/tires, pulling a light trailer on and off since 100K miles.  The AW4's architecture, build quality and torque limits have been tested in a variety of import trucks.

I know that I'm asking a lot, and after reading some of your other threads, I look forward to any advice that you can give.

 

Thank for your Knowledge,

Mike S.