Moses Ludel

Powertrain Control System issues with the E4OD can cause your symptoms. At this point, let's avoid the hydraulic system or friction clutch issues, which generally require a transmission rebuild. For now, I would focus on the VSS. This is a crucial signal in the PCS, and you're getting a clear message of a fault. Before racing to replace the VSS, look for wiring and connector troubles, the easier remedies. If the VSS unit tests defective, I would replace it, regardless of whether there are additional troubles with the transmission. The 12 and 13 codes should also be explored and resolved, though they may have no direct bearing on the 2nd gear skip-and-slip. Also check the shift linkage and the shift module at the transmission for clear engagement in each shifter position. Chock the wheels, set the parking brake, and do not run the engine during this check! You're simply sensing the "feel" of each shift detent position at the transmission's manual lever. It might help to have an assistant move the shift lever. Make sure your helper does not crank the engine over while releasing the shift lever from Park! These are the least costly repairs and troubleshooting steps for openers. We can go much deeper. If you need details on troubleshooting the VSS, just ask. Moses

Case...I was the first person in the U.S. to Rhino coat a Jeep tub. Rhino dealers were well versed on bed liners. I had a friend, Rick Preston at Rick's RV Center in El Cajon, who tipped me off about Rhino with his one-ton Ford dually's bed protection. I was sold on the idea with the caveat you describe: Any coating must go on a clean and rust free surface without voids! That was 1989, the vehicle was an early-'80s CJ-5 project for OFF-ROAD Magazine, and I publicized Rhino. I took "Project Trials Machine" to a Rhino franchisee at north San Diego County. After scratching their heads, they shot the bare tub, fresh out of a light professional primer/sealer job by Louie Russo. (That vehicle has been depicted in my Jeep Owner's Bible since the First Edition in 1992.) Today, Jeep tub coating is common. I have used powder coating, professionally applied bed/tub liner, primer/sealer and paint, spray-on undercoating, everything known. The concern is exactly what you share: a void can lead to treacherous exfoliation rust (nice for book illustrations but dangerous stuff!). Exfoliation can occur with powder coating, bed liner, primer and paint, undercoating and any improperly prepped substrate. The '76-up CJs seem especially rust prone; however, this could also be a reflection on the dramatic increase in the use of salt on winter roads...My CJ-5 suffered from its previous owner's residence at the Rust Belt. I've heard stories from Michigan friends who have seen Jeep frames split from inside-out rust! After a half-century of exposure to the bottom sides of Jeep 4x4s, I prefer seeing what's going on with the chassis. In my view, quality epoxy primer/sealer after complete descaling and cleaning can be a base for a high quality black enamel coating. Done right and spray washed regularly during salted road months, this can hold up and provide protection. If your goal is undercoating, and if you're confident that there is no rust and everything is sealed well, you might consider a commercial undercoating job by a shop qualified. They can apply undercoating uniformly and with even chemistry. If you prefer doing this on your own, 3M does make commercial grade undercoating that could adhere and seal well on a base of black epoxy primer over descaled, clean metal. Between 2005 and 2008, I performed mechanical restoration work on muscle cars and vintage (mostly postwar) classic automobiles and trucks. The variety of work included rebuilding/restoring vintage manual and automatic transmissions and steering gears. Iron and aluminum cases were first pressure washed in a cabinet then bead blasted (which left slight etching on aluminum) before spotless cleaning in the cabinet washer with a thorough flash drying. I found that the best sealing and rust preventative for iron manual transmissions (those that did not require color matching to OEM) was the use of satin or semi-gloss black commercial epoxy primer. I applied this with a spray gun and used a respirator system to prevent respiratory damage and other health challenges. Black epoxy semi-gloss leaves a quality, uniform finish with excellent sealing ability. It works well as a base coat for color, too. The only downside is that this primer does not tolerate UV well and should not be left exposed to sunlight. A manual transmission, transfer case, steering gearbox or Jeep undercarriage should never see the sun—if you keep it topside up! Epoxy primer and quality enamel provide reasonable protection from rock and gravel chipping. Of course, undercoating over epoxy primer, or a primer/sealer and compatible paint with good adhesion, would provide even more chip protection. I'd like to see others jump into this discussion and comment on their best approach for preventing salted road damage and rust caused by humidity at places like Tennessee! Moses

David, by sheer coincidence, I received this press release. Thought you might find the info interesting. This is proactive and a possible link in your quest for E85 kits and insights: Enerpulse Technologies and Green Bridge Technologies Join Forces.pdf I'm working with Enerpulse, testing their Pulstar® energy releasing spark plugs. I've interviewed the CEO at Enerpulse for a pending video on the plugs. Enerpulse's involvement with Green Bridge is a positive on the E85 front. Moses

Exactly, David! The flasher rate will be determined by amperage and resistance load. I doubt whether Honda did anything out of the ordinary here. As you note, there is a rectifier, and the bulbs are normal 12V, presumably. (They could be 6V, but that's archaic even for motorcycles.) This means that the voltage rate must be within norms for a 12V bulb. Flashers like we're discussing will increase the cycling speed rate with longer runs of wire or poor grounds. (This is a DC system where grounds are as important as the hot leads. The system should be negative ground or "Earth" as some call it.) On turn signal systems like we're discussing, an auto or truck pulling a trailer with lighting will cause an older type flasher to speed up its cycle rate. This is due to added bulb amperage load and the resistance of the longer wire runs. The flasher contact heats quicker and breaks the current at a more rapid rate. More modern systems compensate for this amperage load and resistance. My Dodge Ram 3500 hauler doesn't seem to care how much trailer lighting is added. It uses the same flasher system. (These are relay and electronic module controlled.) On older style automotive flasher systems (like what we suspect your Honda XR650R has), you would install a different "trailer light" flasher when towing. Moses

Jeff, grease could back up to the fitting. Here's a Dana-Spicer manual that illustrates the needs for your driveline: Spicer Dana Driveline PDF.pdf On Page 25, you'll get an idea of Dana-Spicer's approach to maintenance. Very stringent at 2000-3000 mile grease intervals! Obviously, this is for fleet operators who actually perform preventive care on trucks. Unfortunately, the illustrations are low resolution (try reducing the image size or zooming out for an improved view), but it appears that there is a grease lip seal at the inside edge of these spherical joints. If that's the case, the lip points inward to contain grease, and you want to pump grease gently through this joint to prevent risking damage to the lip seal over time. My guess is that Dana-Spicer wants lubrication techs to replenish grease regularly, not flush out the entire cavity or stress the seal too much. I would stick with a quality hand gun and premium grease. Avoid mixing chemistry once you have a grease type and brand. Lithium is okay, moly would likely be better here. Starplex II holds up quite well and provides peace of mind. There are several Chevron alternatives if you're curious. I can provide trade names. Starplex II is a Texaco product and may be difficult to source locally. I bought cases of grease gun cartridges from the local Texaco bulk plant and used this grease faithfully on GM live beam axle wheel bearings and chassis needs like yours. We had two Suburban 3/4-ton 4x4s, an '86 and '87, and each had front wheel bearing packs with Starplex II plus periodic lubrication with this same type grease. Moses

rfields223...Would like to know what the Engine Check code reads. Auto Zone and others will often read a code for free on OBD. Or you can purchase a simple and inexpensive code reader (only) that does not do diagnostics. What we need is a code, I'll help troubleshoot from there. Meanwhile, scroll up and read Keithfromphilly's first question and the exchange we shared. This is the kind of trouble we're seeking, something that might connect the Engine Check (actually powertrain, including the transmission) to your symptom. It would be advantageous to find a simpler problem than something deeper within the transmission. Pleased to follow up with suggestions once we get this Check Engine clue. Moses

Hi, jawalter! This is a tricky one. Since you're using a hand gun, there's less risk of over-greasing. This is not part of the U-joint, so don't expect grease to weep from cross-joint seals! You're basically replenishing grease here. Do not apply too much pressure or a large volume of grease. Grease this fitting routinely, just a bit at a time. I use a Lincoln grease tip kit, which I acquired specifically for the ball end extension to service these CV joints. I ultimately found that the pinpoint tip works better, held steadily and with straight-in force. Stay centered on the tiny ball within the cup of this grease fitting. I've had the best success with the pinpoint tip, using a quality, high pressure, professional grade hand grease gun. The grease type is especially critical in this application. I used Texaco Starplex II for years and have experimented with some non-petroleum, bio-degradable types of late. This joint does need attention, though it's not under real load unless in 4x4 mode. Fortunately, on your K5 Blazer, you have free wheeling front hubs. Unlocking the hubs in 2WD mode, the front driveline does not spin continuously—like it does on my Dodge Ram 3500, XJ Cherokee and other 4x4s without free-wheeling front hubs. Lucky Blazer! Moses

jj_jeep...You know, that cracked manifold would make the engine run poorly. The dilution of exhaust and poor back pressure distorts the oxygen sensor readings. It likely did smooth out, and your "knocking" or ping should be gone if that's the case. Fuel efficiency might even pick up. The cracks were not minor and affected some cylinders and not others. Very pleased that the job turned out well. The photos will be helpful to others. You're building on your automotive/Jeep skills and becoming quite proficient here! Who knows, that high mileage 4.0L may still have some life left. You certainly gave it a boost! Moses

Welcome to the forums, David! I'm trusting others will jump into this discussion, and if not, I'll probe into the Mopar solutions or possible conversion components available through Mopar. I would caution that ethanol is very rough on fuel systems, a contributor to corrosion and clogging. On engines with carburetors, ethanol left for any period of time in the fuel bowls will clog jets. I know this from personal experience, especially with smaller engines and powersports vehicles, though it could just as easily happen with automotive and truck engines. Please do some research on the downside of ethanol. A search online would turn up a wealth of details. Try search keywords like "Damage from Ethanol Fuel" or "Ethanol and corrosion". I'm very glad you're a member and am pleased to help answer any questions. Let's see what others say first. Moses

David...Flashers are like a cut-out relay. When they reach a certain load/amperage (which translates as resistance and heat that make the contact open), the lamp-on cycle breaks. Contact cools and returns to a connection, the lamp goes back on. Cycle time depends upon contact resistance and the lamp amperage load applied. Primitive and effective, a flasher with the right amperage or resistance setting should work. Do you have the factory wiring schematic to know which wires apply and where? Moses

David...The source for all of my dual-sport conversion products is Baja Designs. They offer kits for most popular dirt bikes, including my North American XR650R. The Baja Designs systems do use a Ni-Cad battery pack, as lighting with the engine not running is a legal requirement. Does your Euro model run solely off the stator? There are common 3-wire turn signal flashers used in 12V and 6V automotive applications. Some are cylindrical in shape, others are Bosch-type and look like a relay. See your local auto parts source. At the Baja Designs website, you can drill down and access PDF wiring schematics for their various kits. See how the dual-sport conversion drawings compare with your system. Baja Designs does have flashers (check prong count and fit), which are available separately. (These may be common automotive source.) An Email to the tech line saves long distance phone charges and could turn up some answers about the compatibility of Baja Designs flashers with your system. The website is: http://www.bajadesigns.com. See the motorcycle dual-sports section. Let me know if you need more info and how this turns out. Moses

Really nice footage, David...I recognize both the drone perspective and the GoPro for its wide-angle view. Your cam operator made much of the footage look like helicopter vantage, a real accomplishment! I film with a Hero3, the new model is the Hero4, and I'm on for that one, too! GoPro will have a large booth at the SEMA Show, Las Vegas next month. It's like a magnet at this automotive and motorsports show. GoPro has become the norm for action filming, 4x4 and motorcycle racers use it routinely. I use the GoPro for close-up and flowing work as well, including some segments of the HD how-to videos in true 1080P. Alongside an HMC40 Panasonic camcorder and complete Nikon D7100 system, the GoPro rounds out my video equipment for the shop studio and in the field! For your riding angles on the ground, try a GoPro Chesty harness rather than the helmet mount. It's a handy and "real" perspective, I used the Chesty in the Michelin tire testing and road shots of the TCI/Nelson Rigg equipment. The GoPro is the moving footage on the bike. In the Nelson-Rigg video, watch from 6:01 onward to end, you'll like the handheld GoPro close-ups and walk-around plus Chesty perspective on asphalt! I do use the optional GoPro LCD back for framing and viewing the close-up and walk-around scenes. For the road, the GoPro battery lasts much longer without the LCD back in place! There's a new 360-degree pole mount for the helmet available from a 3rd party: www.killershot.com. This is counterweighted, you've got to see it! For catching wheels and all angles of riding as a solitary cam unit in motion, this is the tool. The Go Swivel can provide your front shots, ground level. Share the link and point to the Go Swivel. I'm getting one soon. One caution: Avoid being seen in public with this Go Swivel "propeller" on your helmet! Moses

60Bubba (Case)...Yes, there is a return spring (Mopar Part #J5351050, likely available in the Jeep aftermarket as well). Here is the pedal assembly and all related parts, the spring is item #11: 1981-86 CJ-7 Brake Pedal Assembly.pdf This will help clarify the location of parts, too. Very pleased that you have a safe, quality brake system now! Moses

Case...I hinted that your system looks like the later Mopar EFI Conversion Kit. This was a change in the fuel supply system and the induction manifold and fuel rail. You should still have the 60-Way (pin), single plug PCM. I've tried to guess why the parts change, the two-rail system (1991-95 YJ Wrangler) works well. Likely Mopar no longer wanted to support the 1994-1995 intake manifold, fuel injection rail design and hoses needed for the original kit, which consisted of off-the-shelf 1994/95 YJ Wrangler and XJ Cherokee parts. The OBD-II rulings may also have influenced this change. Regardless, think of your system as essentially off-the-shelf 1997-99 TJ Wrangler. This is handy when you need a sensor or individual components. Note that there is a "custom" fuel pressure regulator near the tank, mounted externally. This is actually a modified 1997-up TJ tank regulator that normally fits atop the in-tank fuel pump on a single rail factory EFI system. The modification makes this a standalone piece that does not mate with the in-tank pump module like a TJ Wrangler. There is no regulator on the fuel rail, the item that looks like the two-rail regulator is actually a fuel pressure "damper" to stabilize fuel pressure. Your later 4.0L engine accommodates this system readily, I did a similar approach for my son-in-law's '87 YJ Wrangler, using a mid-'90s replacement 4.0L long block with your later Mopar EFI single rail package. This made the changeover easier. He's at San Diego County and has passed the referee station inspection and subsequent smog checks. Needless to say, his engine burns very clean, it should meet 1997-up TJ tailpipe readings with the cat in place. This beats both the '87 2.5L TBI engine and the 4.2L carbureted engine. A 4.6L build would be practical if you ever rebuild this 4.0L engine. Beyond the 4.2L crankshaft and right piston/rod combination for correct block deck height, you'd only need to change out the injectors. I talk about this in depth at the magazine. (At the magazine Search Box, simply insert the keyword: 4.6L...You'll get plenty of returns links!) Presumably, with these replacement injectors, the tailpipe readings are within bounds for smog inspections. I've heard no reports to the contrary. Moses

Wow, 60Bubba, this is a substantial upgrade! The master cylinder looks larger capacity, the booster dwarfs the OEM. As a footnote, there should be a slight amount of pushrod play at the master cylinder with the pedal completely retracted. If it was factory set, it should include this slight play. The play allows the master cylinder piston(s) to retract completely and not block the compensating port. If the pushrod does not retract completely, it can trap brake fluid in the system and cause brake drag or even wheel lockup. This is a general concern around setting up a master cylinder pushrod. Power booster pushrods into the master cylinder are set with a gauge and specific height, presumably yours was gauged if sold as a master cylinder and booster assembly. (Manual brakes simply rely on the pedal free-play, which your system requires, too. Pedal free play on your CJ should be 1/16" to 1/4". This is movement felt before the pedal has any kind of resistance from the master cylinder.) The play I'm describing is simply to assure full piston retraction when you release the brake pedal. Worth a peek. Moses

jj_jeep...Should be deep cup and readily available. Remove your old ones first and compare depth of edge with new plugs. Both types should be at the local NAPA store if reasonably stocked. The block heater has an expander that loosens with the bolt in the element's center. Loosen the bolt (not completely, or you may be digging parts out of the block passageway!). The replacement unit uses an O-ring, and if the OEM has the O-ring, you may be able to "repair" your existing heater if the element still works. The leak could be a loose or deteriorating O-ring. I'd take the unit out if it's leaking and go from there. You may be able to simply replace the O-ring with a reasonably heat resistant and anti-freeze suitable O-ring. I looked in the Mopar parts catalog, they do not show a replacement O-ring. You'll have to play this one out and see what's in there. Do not attempt to "rotate" the block heater as you would a freeze plug. It will come out and go back into the bore straight, just as you suspect. It can be indexed if necessary but not pivoted. Do not hit the heater element with a punch or hammer! Moses

This is very helpful information for other CJ owners, 60Bubba! What a dramatic difference, and clearly from just the booster and master cylinder change. Iron is still my favorite master cylinder material. The MBM master cylinder and Restoration Performance dual diaphragm booster sound like the way to go. The OEM boosters and check valves are now long in the tooth and likely in need of replacement. Good to change out the master cylinder at the same time, as the added boost would overwhelm worn master cylinder seals. Cost, overall, seems reasonable. As for the switch to synthetic brake fluid, unless stated that it will mix readily with conventional DOT 3 or DOT 4, you did need to remove and flush out all of the original fluid. DOT 5, specifically silicone brake fluid, is not compatible with DOT 3 or DOT 4. DOT 5 must be replenished or topped off with DOT 5 as well. Never mix this chemistry! I like a vacuum bleed, as it pulls all old fluid and debris from the wheel cylinders and caliper chambers. Pressure bleeding will force debris to the cup seal edges of the wheel cylinders or the caliper piston gaps and leave it there. For a complete fluid change, I use a pneumatic vacuum bleeder that has a large dirty fluid reservoir, bleeding from the caliper and wheel cylinder bleeder valves. Please share some photos of the new master cylinder and booster in place! Use the "More Reply Options" below the editor box (right side) to find and place your photos. Moses

I am pleased that moving the intake manifold out of the way and plastic tying it to the core support rod did the trick, jj_jeep! This is such a time and labor saver. The complete removal of the intake manifold and keeping track of all the components can be a major chore. The old exhaust manifold is suitable for framing or hanging on the garage wall...Just kidding, it's truly ready for scrapping! From the great photos, your freeze plugs look shot. You need to replace these plugs while they're easily accessible. By now, you've discovered the coolant leak, right? For those unaware (Florida and Southern California Jeep owners), the last freeze plug looking device with the electrical connector is the block heater. Is that your leak source? It looks so, but this is the more costly piece to install. If the heater unit has a cinch/expander bolt, try carefully tightening the expander. This may reseal the plug. If you're not confident of the seal, and if you use the block heater, price a new heater unit. (Here's the best deal I could find for a genuine Mopar assembly: http://www.amazon.com/Cherokee-Engine-Heater-Mopar-82201506/dp/B007NPL3OM. There are aftermarket units available for much less. I'm use an aftermarket Kat block heater on the Cherokee, no trouble to date, though the Mopar unit is more rugged.) Each of the other freeze plugs is a typical cup type. Since you are likely going to replace any suspect plugs, I'll share my technique: 1) Take a blunt or rounded punch and tap just inboard of the cup lip (on the dished area). Do not punch a hole through the cup, you want to rotate the cup in the block bore and avoid driving the cup into the cooling passage if possible. 2) Whether the plug drives into the passage or rotates as desired, I grab the cup edge with a channel lock pliers. Prying carefully, avoid scratching or marring the cup bore in the block, rock the channel lock's head to apply leverage. (Pry against the block and not the bore.) Cup perpendicular to the block now, pull the cup outward through the plug bore. Do not leave broken cup pieces in the block, they will obstruct coolant flow. 3) Take crocus or emery paper (preferred for a corroded surface) and clean up the plug bores. Avoid gouging or making deep scratches. The new plug must seal completely in the bore. 4) I coat the outside edge of the new steel cup (not brass at this mileage, steel is stiffer and holds shape better than brass) with traditional Permatex Super 300 Form-a-Gasket sealant or equivalent. I do not use RTV sealant here. Coat evenly and apply a thin additional film around the block freeze plug bore. You don't want excess amounts, as this will wind up in the block and can migrate and clog the radiator tubes. 5) There are freeze plug driver tools, usually with a swivel head. I've done just as well by starting with a plastic sand filled head hammer, tapping side to side until the cup is clearly going straight into the bore. Often, a heftier hammer and block of wood can drive the freeze plug into the bore evenly. If not that easy, try an impact socket with an O.D. that fits just inside the cup edge. Drive straight and avoid distorting or badly nicking the cup dish. Avoid distorting or denting the cup's raised edge. If unclear how deep to set the plug, note the OE installation. I seat the cup edge even with or slightly deeper than the inner edge of the chamfer at the block bore. This is a much easier task now than with the manifolds in place! Regardless of the life left in this high mileage engine, you need dependability. These freeze plugs are on their way out and could spring a substantial leak at an inopportune time or place. Share some pics with us. It will be interesting to see how close to failing these freeze plugs turn out to be. Moses

Hi, Jeeplady95! So, you have a 4.0L inline six-cylinder engine? That would be the AX15 transmission. The four-cylinder 2.5L uses the AX5. Here are the official Mopar part numbers for the complete transmissions offered in 1995 Jeep YJ and XJ vehicles: TRANSMISSION ASSEMBLY 5 SPEED 52108022 XJ 2.1 Turbo Diesel Engine 1994 52108121 X1,XJ 2.5 Turbo Diesel Engine. 1995 52108049 YJ,Y1 2.5L Four Cylinder Engine, 4WD 52108045 XJ, X1 2.5L Four Cylinder Engine, 2WD 52108046 X1 2.5L Four Cylinder Engine, 4WD, EGYPT, MALAYSIA 52108046 XJ 2.5L Four Cylinder Engine, 4WD 52108021 X1 2.5L Four Cylinder Engine, 4WD, CHINA, ARGENTINA, VENEZUELA, MALAYSIA, EGYPT 52108050 Y1, YJ 4.0L Six Cylinder Engine 52108048 XJ, X1 4.0L Six Cylinder Engine, 2WD 52108047 XJ, X1 4.0L Six Cylinder Engine, 4WD 53009526 ZGZJZ1 4.0L Six Cylinder Engine 52109021 ZGZ1 2.5 Turbo Diesel This Mopar part number should be located on the top of the transmission case if the assembly is the original for this Jeep. (This 53005385 unit came from a 1991 Jeep XJ Cherokee.) Here are some identifying features of an AX15 for a YJ or XJ Jeep. Note that this unit has only one electrical wire, at the side of the case, and the switch is part of the backup light circuit: It would also be helpful to watch this trailer for my Vimeo On Demand how-to instructional video on rebuilding the AX15 transmission: If you do have an AX15 transmission that requires rebuilding, and if you're planning to rebuild the transmission yourself, the entire bench rebuild and restoration is covered in the HD video rental at Vimeo On Demand: https://vimeo.com/ondemand/ax15rebuild. Each rental period is 30 days to provide plenty of time for getting parts and performing the work. I have the vehicle decoding chart. If you furnish the letter portion of the VIN (do not need your serial numbers), I can clarify. It still comes down to the AX5 with 2.5L four and AX15 with the 4.0L engine. The only "G" in the VIN decode has to do with GVWR (Gross Vehicle Weight Rating). We can address more of your questions about the Wrangler's transmission... Moses

jj_jeep...I did not remove the EFI components. Just use good judgment and do not stress parts. For your application, watch the cables, wires and hoses. Go slowly to avoid stressing parts, disconnect any susceptible part and identify it with masking tape and a Sharpie if necessary. Move the manifold(s) just far enough for removal. If for any reason you do remove the fuel pressure hose, use the proper release tool at the spring connector. Lisle and others make inexpensive spring release tool kits for A/C, fuel and other pressure/spring connections. Do not force this hose connection apart, you will create the need for a very costly repair. Glad you found a cost-effective solution. I've had no trouble with the Borla, it's quite hefty and well-flanged. The issue overall is metallurgy and stress. Heat cycling stainless steel is a dicey proposition over time. Any tubular manifold would eventually fatigue and crack. I like the Borla for its thicker tube walls and smoother bends. I noticed on your OEM manifold, as with my XJ Cherokee, the tighter end bends look susceptible to cracking. And they do! Please share your installation details and how well the Dorman replacement manifold fits... Moses

Ron...Correct about the turn signal. Should only work in the KEY ON and possibly the ACCESSORIES position, depending upon the make and model. I drilled down in the 1987-90 Jeep XJ Cherokee Mopar parts listings, and the ballast resistor does date back to 1987. Here is the 1987-90 Mopar parts catalog showing the ballast resistor, part #24: 1987-88 XJ Cherokee Front Engine Wiring Harness with Ballast Resistor.pdf Note from parts coverage that the 1987-90 period is indicated here. This listing for the ballast resistor does not indicate a particular model year, which means the part is applicable to all years 1987-90. The Mopar part number for the ballast resistor is 33000682. When I run this as a Mopar number, the fitment is as follows: This product fits 63 vehicle variants. JEEP: 3 models, 63 variants between 1987 and 1993 Here's a listing for the ballast resistor that clearly indicates 1987 fitment: http://www.moparpartssource.com/a/42361045__5564270/HARNESS--ENGINE-COMPARTMENT-4--6-CYLINDER-ENGINE-CHEROKEE--WAGONEER--COMANCHE/000018WE.html. The part is inexpensive (under $7 plus freight from this source). Likely the ballast resistor is available in the aftermarket as well and from local sources. So, either all of this information about a ballast resistor on a 1987 model (including the wiring harness schematic, the factory parts manual and a factory service manual) is incorrect, or we haven't found the ballast resistor on your 1987 Jeep XJ Cherokee 4.0L MPI model yet...You can zoom-in on the wiring harness illustration to pinpoint the connectors for the ballast resistor. There should be two spade/female terminals unless someone has eliminated or relocated the ballast resistor. If the resistor has been eliminated with a splice of the two leads, check voltage at this point. It should read the same as the battery voltage (12.85-12.95 volts for a new and fully charged 12V battery without the engine running). The reason for the resistor is to lower/regulate voltage in normal fuel pump running mode (not the cranking mode or under wide open throttle, as we've discovered). The battery and circuits line voltage with the engine running and alternator charging can exceed 14 volts, which apparently is not what the fuel pump should receive in normal operating mode...See if the engine front harness illustration helps, Ron. Here is the 4.0L fuel injection wiring schematic for the 1987-90 Jeep XJ Cherokee. You asked about pre- and post-ECU wiring, this covers what you wanted to know. Note that the wires to the ballast resistor are orange with a black stripe, both in and out of the resistor (Illus. #21). There is a reference note indicating that the ballast resistor is "near the air filter [box]". This color scheme connects to a pink/black wire that goes to the fuel pump at the tank: 1987-90 XJ Cherokee EFI-MPI Wiring Diagrams.pdf Moses

Explore the relay's function, Ron...Keep looking for a ballast resistor. The PDF is 1989 service information. I would expect this to be the same for '87-'90, but maybe '87 is an exception, or the ballast resistor might be elsewhere—or by-passed? Perhaps 1988-90 added the resistor after experiencing a problem with the '87 model? We can explore this further. The ignition switch can always be a source for voltage drop, good thought. Worth at least probing the contacts and testing the switch's input and output voltages. Fortunately, the switch and its connector are not that difficult to access on the XJ Cherokee. This is a possibility. For the voltage drop you describe, there would have to be a poor connection or high resistance at the switches contacts. I'd expect this to impact other circuits, but with relays, maybe the voltage is strong enough to close the relay contacts. Here's the relays identification drawing and part numbers for a 1987 Jeep XJ Cherokee: 1987 XJ Cherokee Relays.pdf. See if this helps, too. Moses

Hey, Ron...I drilled deep on this one and may have a solution for the fuel pump voltage issue. Your Renix fuel supply system does use a 12V pump, and you're very right in expecting a clean 12V signal at the pump. There is one item in this electrical supply to the pump that may be the trouble spot. Your system uses a ballast resistor, mounted at the left inner fender panel in front of the EGR solenoid. This is a typical ballast resistor with one wire in and one wire out, easy to recognize. Apparently this is used to clean up the voltage signal to the fuel pump, which has a 12V permanent magnet motor. 1987-90 Cherokee Fuel Pump Ballast Resistor.pdf Location of fuel pump ballast resistor on 1987-90 XJ Cherokee with Renix MPI Check the voltage at each side of the ballast resistor. If the motor requires 12VDC, and if there's a drop here at the ballast resistor to the 7VDC that you're finding at the pump end, the voltage drop is right here at the ballast resistor. (The resistor is defective.) If there is 12V on both sides of the resistor, you have a voltage drop between the resistor and the pump, either the ground side or hot lead. I also want you to read this PDF, Ron, specifically the paragraph with reference to the MPI fuel pump functions and voltage sources, as they vary under different operating modes. The ballast resistor, starter relay and oxygen sensor relay come into play: Renix Fuel Pump Electrical.pdf Moses

David, this is utterly amazing, fantastic country! The lake is incredible. Filming vantage, soundtrack and editing are superb! So, who has the drone? Looks like GoPro footage on a 3-axis Gimbal. As for riding, you do have it made. (So do I really, we're on dirt in less than 10 minutes from home and can ride up to 120 miles without crossing a paved road at much of northern Nevada.) You have an enthusiastic riding group with great bikes. Thanks for considering the plain's ecology, looks somewhat fragile and susceptible to injury from wheeled vehicles. We have that at Nevada, too. Most don't realize the extreme fragility of desert. "Pioneering" trails in uncharted areas can result in a 150 year cycle of sagebrush regrowth. Our approach is the Tread Lightly formula: Stick to existing, designated trails, logging roads, mining roads, fire roads, single-tracks, two-tracks, gravel "highways" and such. This is not really inhibiting, just considerate of our outdoor recreational legacy. David, thanks very much for sharing this fantastic footage and helping us wrap our minds around Burundi. You live at one of the world's most pristine venues. Trust it will stay that way, the geography must make this a remarkable tourist destination and living space! I would really enjoy sharing a trail or plain at Burundi—or dirt motorcycling and four-wheeling on Nevada's widely varying terrain. The mean elevation at Nevada is 5500 feet elevation, much like Burundi, I would think. We have everything from stark Mojave-type desert to peaks nearly 14,000 feet with high desert flora, alpine forests and even a few glaciers—all within the State of Nevada. I'll share more over time...Can't wait to learn more about Burundi! Moses

David, this is utterly amazing, fantastic country! The lake is incredible. Filming vantage, soundtrack and editing are superb! So, who has the drone? Looks like GoPro footage on a 3-axis Gimbal. As for riding, you do have it made. (So do I really, we're on dirt in less than 10 minutes from home and can ride up to 120 miles without crossing a paved road at much of northern Nevada.) You have an enthusiastic riding group with great bikes. Thanks for considering the plain's ecology, looks somewhat fragile and susceptible to injury from wheeled vehicles. We have that at Nevada, too. Most don't realize the extreme fragility of desert. "Pioneering" trails in uncharted areas can result in a 150 year cycle of sagebrush regrowth. Our approach is the Tread Lightly formula: Stick to existing, designated trails, logging roads, mining roads, fire roads, single-tracks, two-tracks, gravel "highways" and such. This is not really inhibiting, just considerate of our outdoor recreational legacy. David, thanks very much for sharing this fantastic footage and helping us wrap our minds around Burundi. You live at one of the world's most pristine venues. Trust it will stay that way, the geography must make this a remarkable tourist destination and living space! Moses