Stinger87

Little Dana 35 doing work at 180000 miles

Adam f yes my overall issue was my fuel pressure regulator. On top of that the spring was worn out too. I had a few other issues such as a partially clogged fuel pump because the sock fell off the pump somehow. I'm guessing it wasn't properly installed. Since I had that issue, I changed the fuel filter then I realized that gunk made it into my injector and was keeping it open. So after the spring and regulator pump filter and injector, it ran like it should. Currently I still have a slightly rough idle once my jeep gets warm but I have zero performance issues now. Let me know if this helps, and if not, we can try something else.

I traced all of my vacuum lines and they match to my haynes manual. The only thing i guess that could be faulty is the purge solenoid. Ill check to see if i can find some tests to perform on it.

Today i installed the new spring, new regulator and new fuel bowl. The parts that i got actually looked like the original (bad) parts that i first took out. Definitely go with Motor Man parts over auto zone, rock auto, Napa etc. These guys have quality parts that work excellent. I hooked my TBI up and used the fuel pressure tester and fired up the jeep. The jeep instantly turned over and idled perfectly and quiet. The psi reading was exactly 15psi and did not bounce at all just a steady and solid 15. I noticed that i still had a minor sputter so i checked my tps voltage and everything was still with in specs. The second thing i did was to see if i still had a sputter if i disconnect the hose from the EGR valve and my sputter instantly cleared up. As of right now i have the EGR disconnected because it runs great without it. I then took it for a ride and it is running perfect i have zero complaints about it. I had good power through all gears feels about what a 4 cylinder should have. I believe i shouldn't have any more issues with the fuel system/engine for a good while. I am going to run it all weekend and week to see if everything holds up and i will get back to you for hopefully a final post in this thread. Here is my gauge hooked up after i re installed the new spring and new regulator and also the new bowl. Here you can see the difference in the regulators. The one on the left is from Motor Man which looks exactly like the original. The one on the right is the same ones that rock auto, Napa etc will supply. I feel if the regulator on the left was good enough for Jeep to use then its good enough for me and that's the one that i used. Here i have my two springs, the one on the left is the original i believe from 1989 and the one on the right is from Motor Man. It's a small difference but you can clearly see the original is slightly worn out. The one or the right is about 1/8" taller then the original. With that small of a difference it changed my fuel pressure from 16-17 to 15 psi and now my jeep runs perfect. Also, like Moses said, this proves how important the correct fuel pressure is. I had a lot wrong with my jeep and now i feel i can finally close this chapter and finally enjoy driving my jeep around and now have some money for other add-ons for it!

I just received my parts and they look exactly like the factory ones. I am not sure where they get them from but they look legit. The spring is large like the original one and even the regulator looks the same too. The other regulators had minor discrepancies when compared to the original but this one is spot on. I'll have more time Saturday to do everything to it and get back to you.

I will check when i get home to see if it is california emissions which i do not think it is. Secondly on the Crank position Sensor if i take it out to clean it do you know if it came with a factory spacer to set up the correct positioning of the sensor or is it just plug and play on this model. I know some of the crank position sensors i deal with will have a small spacers on the end of the sensor and once you crank the engine over it removes the spacer. I am pretty sure this one is plug and play just checking before i mess with it. Again thanks for all the help this far! I think i can finally see light at the end of the tunnel

Just made a purchase from Motor Man fuel injection and customer service was excellent. Quick easy and friendly transaction. The gentleman that i spoke with told me that my spring in my regulator bowl was faulty. With his set up, the new fuel bowl and spring will provide the correct PSI needed to run the jeep at factory specs. I told him mine has a broken off adjuster screw and he said it sounds like someone has tampered with it in the past. Maybe maybe not. I will have the parts by thursday so hopefully after work i can install those and get another reading. If my reading does not change i may try another gauge to ensure mine is reading the correct pressure. If both gauges compare then i will go back to looking at my return line. The return line will be the last part of the project that could cause my fuel pressure to be slightly off. Crank Position Sensor- is there anyway way of testing this sensor. I know i can check for ohms but i do not know what the factory specs are.

Alright so i found a company that sells just about everything you need for the tbi engine on the jeep. They have kits for the regulator, spring, bowl and screws for $30 which is almost half the price of the regulator from napa alone. Anyway the company is called Motor Man Fuel Injection. I am going to give them a call tomorrow to see if their bowl has the adjuster screw or not. Ill post back again tomorrow about this. Here is the ebay link i found http://www.ebay.com/itm/New-Jeep-comanche-wrangler-cherokee-TBI-Fuel-Injector-regulator-rebuild-kit-2-5L-/290612842207?pt=Motors_Car_Truck_Parts_Accessories&hash=item43a9e00edf&vxp=mtr

The jeep does run pretty good at 16-17 psi but I can feel the sputter a little bit at low rpms. I've already done so much work to it in not going to settle until it is running 100%. Tomorrow I am going to use a drill press to make a small hold in the current adjuster screw then use a bolt extracter to remove it. I want to install my own adjuster screw to set the pressure exactly where I want it. The thread pattern looks very course and might be hard to find a bolt with the exact match. Also the return line looks like it is free of restriction but I may go ahead and replace it with a fresh line. Future reference for my next fuel pump I do on it I will probably make it common practice to change that line due to the fact you have to just about drop the tank to get to it. I'm going to check eBay real quick to see if I can find any used or new bowls for sale.

oh yeah i forgot to add that i re-installed the factory spring. The spring was in the picture i posted a while back but it was the huge spring. So for future reference for someone that has to do a fuel pressure regulator on this don't use the one that the parts store supplies with the regulator unless you know for sure you can adjust your regulator to the appropriate specs. Again the spring supplied from the store was about 15 psi too low compared to the factory one.

Finally got a fuel reading and almost positive on why my emissions levels were horrible (excessive Fuel pressure). On top of that i got my new vacuum lines installed, new injector and orings (injector no longer drips with key on engine off) . For my PSI readings i had aprox 16-17 psi which is too high. I need to be around 14-15. The weather here is terrible right now so i didnt check for kinked or blocked return lines. Tomorrow it should be decent out just cold so i will check to see if there are any messed up return lines. Worst case scenario would be having to remove the bowl from the TBI and drilling out the old adjuster screw. That wouldn't be too terrible i could take it into work and i have all the tools there to make it an easy job. I did not drive the jeep but i am pretty sure that the jerking/ bucking is gone. It was bucking i believe because my fuel pressure was around 1 psi. Ill do another post hopefully tomorrow to let you know if my fuel return line is messed up.

Today I didn't do a whole lot with the jeep but I yanked the tbi off the top of the motor to thoroughly clean and go through it. I'm going to replace the 4 vacuum lines on it and inspect all the ports to make sure they are free of contamination. I am also curious if there are torque specs for the brace that holds down the injector and for the three screws that hold the regulator bowl in place. Other than that once I get the new injector o rings and vacuum lines and install the factory regulator spring I will be testing for pressure again. I should have another update come Saturday.

ok new discovery, my gauge does work. Now that i know my gauge is working that leads me to think the jeep's fuel pressure is pretty much at zero. Yes the pump is pushing fuel but i am thinking it has to do with the regulator and that small spring that i installed. What i will do is reintall that old spring that was larger and then check my fuel pressure. Earlier i was saying that the large spring was causing too much pressure but i need to be able to get some sort of reading. If my pressure is too high i should be able to either find a new spring or get an inline regulator. I am not 100% on all of this but it sounds like a good direction to go in. My symptoms right now sound directly to being a fuel problem. Idles good with the fuel its getting but once you put a load on it and accelerate it doesn't have enough fuel to compensate for the amount of air coming in. Currently we are in the middle of a rain/snow storm so hopefully i will have some more updates soon.

In my picture i have a bass fitting connected into the test port near the return line thats the only reason it looks slightly different. From what i can tell i have it set up exactly how the books pictures for a TBI engine has it set up. It looks like a fuel line but its just the brass fitting i used in the test port to hook up my gauge. I then ran a line to my gauge from that port. I turned the key on heard the fuel pump turn on but the gauge had 0 on the reading. That is when i removed the gauge and hit the key to make sure pressure was getting to it and a powerful line of fuel shot out. I also took the gauge to work and used our shops fuel pressure set and hooked it up to a MPI engine and it still had zero psi. im going to see about borrowing a gauge from work or purchasing another one. This here is kind of getting ahead of myself but on the bowl that the fuel pressure regulator and spring sit in, at one time it did have the adjuster screw in it but looks like someone cut and ground it off so no more adjustments are able to be made if need be. With that being said any ideas on where to get a new one because i cannot find a part number and i hope i wouldnt have to buy a new unit.

ok so here is what i got so far. I got a line made for the fuel pressure tester to hook right up to my tbi unit but it appears that i have a faulty gauge. I know i have a good amount of pressure to the gauge because when i disconnect the gauge and turn the key fuel shot about 4-5ft. I shouldn't be shooting fuel everywhere but working solo and having to reach in turn the key while keeping an eye out for pressure this seemed to be the only way. Anyway the jeep does fire right up but the spray pattern coming out of the injector now is horrible. I'm going to check to see if i can take it apart and clean it and if not ill just get a new one because it looks to be clogged with contamination from the tank. I have two picks of how i set up the fuel pressure line if anyone needs more pictures i can grab more.