Disturbed

I ran through the first 5 steps and actually discovered 3 things. 1. The C101 connector had already been cleaned out, no black tar and it looks to be in good shape, someone had even added some sort of gel, like you see in the gel filled connector, to prevent corrosion. 2. The ground strap at the rear of the head was MISSING, nothing there, but there was one on the intake manifold so I picked up another ground strap at NAPA and added it to the rear of the head. 3. I definitely had an issue in the grounding in the wiring harnass, probing the TPS and checking to battery negative I would see the continuity come and go when shaking the wiring harnass. Pulled the wiring harnass apart and did the sensor ground upgrade, everything seems good now, time will tell but it has been fine since Saturday. Thank you very much for your help.

Yes it is an 88, sorry I didn't mention that. I found your post and bookmarked it, I will try that tonight. SUPER important to do all 5 of them. Won't take but an hour and half maybe. I printed your tips out and as soon as the weather cooperates I will be going through at least the first 5, all of them if I have the time. Thank you very much for your help.

Yes it is an 88, sorry I didn't mention that. I found your post and bookmarked it, I will try that tonight.

I think these two issues may be related but am not sure. My MJ decides at random not to start, always when it is a cold start and have never had it die while driving. Sometimes I can let it sit for a few minutes and it will fire right up, sometimes it takes longer until it will start, this weekend it just refused to start. I was getting no spark. Pulled the coil and ignition module, coil tested OK after I cleaned up the terminals but decided to replace it anyway since the terminals were corroded on both the coil and the ignition module. Threw the new coil in, nothing. Had AutoZone order me a new ignition control module for Sunday. Sunday I installed the new ignition module and it started right up, no issue and was running very smooth. For kicks I put the old ignition module back in, and it fired right up. I was still hopeful that it was a flakey module, had one on a YJ I had and a new module solved the problem. Put the new coil and module back in and called it a day. Monday morning started right up to go to work, and to go to lunch, and to go home, started a few times last night shuffling cars in and out of my garage doing maintenance on them and running to AutoZone to get an oil filter for my wife's car. No issues with the truck all night. This morning me and my boy hop in the truck to get him to daycare and it will not start. Same thing as before, cranks fines but no fire. Let it sit a minute or two, nothing. Couldn't wait any longer so we hopped in the ZJ and I took him to daycare. Ran back to the house after dropping him off to try it one more time before work, still nothing, just like it was doing on Saturday. I am not sure if it is a related problem but when I crank the engine over longer than normal, sometimes when I release the key the engine just keeps right on cranking. I believe that problem may be in the starter relay that is on the fender, I was going to replace that as well but AutoZone did not have a listing for that and I have not had an opportunity to look elsewhere. I am not sure if these issues are related and they very well may not be, the truck is 25+ years old after all, multiple unrelated issues at the same time would surprise me. If anyone has any ideas I would greatly appreciated.

Well I tried to post a reply with pictures as to how I am accomplishing this but I was getting this error, "You are not allowed to use that image extension on this community." I have no idea what that means put here is a link to my local Jeep club board where I am also posting what I am doing. If you want to check out the pictures, not all of it is very interesting but I built a pretty trick skid/protection plate for the fuel filter since it will be mounted on the front of the gas tank skid plate. http://www.jeepsrus.org/MegaBBS/forums/thread-view.asp?tid=3490&posts=7#M20347 I'll post an update once it is in a running.

Thank you gentlemen. I had a response typed up to the "that's stupid" response but as far as I am concerned I am a newbie on this site and did not feel it was in my place to start something or challenge someone who is obviously a long time member. I have a real problem keeping my hands on things, if the fuel tank wouldn't be so new I would be putting a fuel cell in it too. I actually was checking out the JAZ fuel cell sitting in my shop for my buggy rebuild but it wasn't quite right as far as I was concerned and I would like to keep the stock filler location. This is not a wheeling rig, it is my DD. I have had a lot of luck with using external fuel pumps. Not sure about the jet turbine idea but my cousin-in-law seems to fall into 5.9 ZJs all the time, I think he has 3-4 or them right now so there is always the 5.9 option....hmmm. I will post up some pictures when I get it installed. Just got notice that the pump has shipped from Summit, I should have it tomorrow.

Unfortunately every one I have seen will not even mount in my mount without hacking up the the top cap portion of the mount that holds the pump in place. If I am making changes I would prefer to do the external pump set up. I have run a number of vehicles with external inline pumps and they don't bother me. Sure they are louder but this is a 24 year old truck, its not like I can hear it over everything else. Besides the one that just failed was not super quiet. I am all about being able to swap a fuel pump with a screw driver and a couple of nut drivers.

The Summit pump is already on the way, the E2000 pump costs slight more than the universal pump I purchased. The return line and the regulator on the fuel rail are still in place so there should not be an issues there. I guess we will find out when I get the pump gets here is everything works like I think it will.

Well the fuel pump on my MJ finally went out. It had been getting louder and louder and I knew it was on its last leg and was just a matter of time. It left me sit about 2 weeks ago. Finally last weekend I got to look at it.. Pump has power and everything is functioning as it should expect for the pump. Dropped the tank and pulled the pump and tested on it the bench. 12v directly to the pump and nothing, it is locked up. Spend a bunch of time trying to find a fuel pump to replace the in tank unit and it seems I have an odd pump. I checked a number of places online, had Napa order in a few different pumps that were not the same as mine, checked with the dealership to find the pump is discontinued from Chrysler. Everything I have seen is close but none of them will fit the mount . If you are familiar with the stock pumps and the way they look everything I have found has four "lobes" on the top. My pump only has three "lobes and the mount is made specifically for a that shape on the top of the pump. I reached a frustration point and ordered up an external pump from Summit Racing. This is the pump I have on the way, http://www.summitracing.com/parts/sum-g3138 45PSI/43gph which should work well with the MJ. I have a number of vehicles I have run on external fuel pumps and have never had any issues with them. I am going to extending the pickup down to the bottom of the tank using metal fuel line and retain the OEM strainer. Also plan on retaining the fuel level float. Pump will get mounted on the frame rail near the fuel filter. It should not be too diffiult. I am hoping the pump shows up tomorrow so I can work on it over the weekend. The only down side to this project is I must do it outside. I have a big garage with a lift in it but unfortunately it is full of projects including my Rock Buggy on the lift that is missing most of the tubing and the rear air shocks so there is no way to move it. If anyone has tried this before using a stock tank I would like to here about your experience with it. I have done it on a Jeep YJ with a stock fuel tank for a TBI conversion but never on a multiport injection system. I will try to get some pictures once I have this done.

OK I was able to fix this problem, it was in the TPS. I am thinking in the plug. I pull the connector off of the TPS to test the wiring, everything tested fine. Plugged to TPS connector back in an back probed the TPS, all of the readings were good there also. Fired the MJ up to see if it made any difference with it running, no everything tested fine but I also noticed that when I revved it up it was no falling on its face. Took it out for a drive, problem was gone. Drove it about 30 miles between yesterday and this morning to work and the problem seems to be completely gone. I am thinking that one of the pins in the TPS connector was not making a good connection anymore, from unplugged and plugging it back in and messing around with the pins while doing the testing that connection issue has been corrected and now the ECU is getting the reading it needs. Either that or is was just a coincidence that the problem went away after messing with the TPS. In either case my MJ is back on the road.

OK worked on it more today. Replaced the IAC, not that I thought that was a problem, but I knew it was problematic so i replaced it. That fixed the idle problem but not the stubbling issue. Also replaced the MAP sensor, call it a shot in the dark, no difference. Tried bypassing the fuel pump ballast resistor and that made not difference. Tested the EGR solenoid and it functions properly. Hooked a vacuum pump to the egr valve and you can see that cycle so it seems as if that is working although bypassing that permanently might be a good idea. It acts the same way whether the truck is warm or cold, when I did my test drives today I started it up and ran 1/4 mile down the road and back, same issue so it was not warm enough to pull the EGR valve in. Still seems like a fuel issue but I hate to replace the fuel pump just to check it, especially since the fuel pressure tests OK and I can get it to do this in the driveway and see that the fuel pressure is not dropping. Any other ideas what may be causing this? Anybody think the TPS could be causing this? Since it does it warm and cold I do not think it could be the CTS, besides at WOT the computer should be running in open loop mode and ignoring the CTS. It does this in both open loop and close loop mode. If the engine runs fine an idle I think that rules out the CPS and the sensor in the distributor, if there was an issue there I would have an issue at idle and when cursing but the truck runs fine at an idle and when curing under light load. Load should have no affect on these sensors if there was an issue with them, am I wrong about that? Considering replacing the fuel filter. and just because it is cheap and easy. I am really going to kick myself if it does turn out to be the fuel pump. Anyone have a good plce to buy a fuel pump at a good price, the pump in my truck is a Bosch pump. Any idea's someone may have would be greatly appreciated, I really want my truck back on the road, I miss driving it.

No cat and the exhaust is all new from the manifold back in the last year.

I agree but I can get it to die just revving it up sitting in the driveway, even when it dies the fuel pressure is still reading between 30-39psi depending how hard I hit the throttle. I would think if the fuel filter was plugged up I would see a drop in the fuel pressure when it dies off and I don't, it seems to have plenty of fuel, if the pump wasn't keeping up, whether it is the fuel pump or a plugged filter I would see the fuel pressure drop off when I rev it up but I don't see that. Fuel pressure never drops below 30PSI and increases when the engine is revved up, That is what has be so confused. Thinking maybe I will try bypassing the fuel pump resistor to see if that makes a difference.

OK finally got around to messing with the MJ. Put a fuel pressure gauge on the rail. 30PSI at an idle, 39PSI with the vacuum unhook from the pressure regulator, Jumps from 30psi to 39psi when I try to rev it up but it still falls flat on it face, so it does not seem like a fuel issue. The truck had sat for a few days without being driven before this started to I pulled the air filter to see if some critter has built a nest in the air box, nothing the air box and filter are clean. Like I said the IAC was giving me issues so I am going to replace that but do not think that would cause this issue. If the fuel filter was clogged I would think I would see that in the fuel pressure. Anyone have any other ideas. It getting expensive driving my V8 ZJ and I want me truck back up and running..

That will be my first step when I have a chance but I didn't know if the resistor for the fuel pump would cause something like that, I am not very familiar with that setup and and do not know if a faulty resistor could cause issues like that.