Ωhm Posted April 23, 2018 Share Posted April 23, 2018 Were the old plugs fouled out rich? Carbon/fuel soaked. Link to comment Share on other sites More sharing options...
dkenitz Posted April 23, 2018 Author Share Posted April 23, 2018 I'm no expert, but the old plugs did look to have a lot of carbon deposits and to me indicated a rich condition. I'm not sure if that was due to the mix n match set of old plugs, the vacuum leak that existed prior, faulty injectors, etc. Link to comment Share on other sites More sharing options...
Ωhm Posted April 23, 2018 Share Posted April 23, 2018 If the remaining plugs are similar to the one shown, that's a good sign. Now back to the fuel pump and no pressure on shut down or key on. Anyone care to comment on OP's choice of fuel pump. Carter P74155 fuel pump kit. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 23, 2018 Share Posted April 23, 2018 The plugs look fine. There are plenty of posts regarding Carter pumps as being DOA right out of the box. I've always used Bosch replacement pumps and have had good results, as have most of us. FP pressure should jump up almost instantly on startup, and shouldn't slowly oscillate when idling. Fuel filter fresh? The check valve appears non-existent on your rig; it should hold pressure much longer. But there are other causes for rapid fuel pressure drop. There are a couple of test that can be performed to keep from replacing parts not needed. First with engine up to temp with fuel pressure gauge connected, find the return fuel line where it is rubber and is accessible to clamp with flat blade pliers. Start engine, read gauge, clamp return line. Pressure should go up to 70>90 psi, then turn engine off with line still clamped. If pressure drops it will indicate a bad fuel pump check valve. if pressure stays up or drops a small amount it will indicate either a leaky regulator or injector, if pressure drops steadily it will be an injector. Link to comment Share on other sites More sharing options...
dkenitz Posted April 23, 2018 Author Share Posted April 23, 2018 2 hours ago, Ωhm said: If the remaining plugs are similar to the one shown, that's a good sign. Now back to the fuel pump and no pressure on shut down or key on. Anyone care to comment on OP's choice of fuel pump. Carter P74155 fuel pump kit. All 6 plugs looked about the same. 2 hours ago, HOrnbrod said: The plugs look fine. There are plenty of posts regarding Carter pumps as being DOA right out of the box. I've always used Bosch replacement pumps and have had good results, as have most of us. FP pressure should jump up almost instantly on startup, and shouldn't slowly oscillate when idling. Fuel filter fresh? The check valve appears non-existent on your rig; it should hold pressure much longer. But there are other causes for rapid fuel pressure drop. There are a couple of test that can be performed to keep from replacing parts not needed. First with engine up to temp with fuel pressure gauge connected, find the return fuel line where it is rubber and is accessible to clamp with flat blade pliers. Start engine, read gauge, clamp return line. Pressure should go up to 70>90 psi, then turn engine off with line still clamped. If pressure drops it will indicate a bad fuel pump check valve. if pressure stays up or drops a small amount it will indicate either a leaky regulator or injector, if pressure drops steadily it will be an injector. Dang it, I should have waited a few more hours to place my Summit order. Purchased the Carter fuel pump kit this morning along with Taylor wires, a new Actron fuel pressure tester, and a Wix fuel filter. The previous owner said the fuel filter was changed recently but I'm going to replace it for my peace of mind. Hornbrod, is this the Bosch fuel pump kit you are referring to?: https://shop.advanceautoparts.com/p/bosch-electrical-fuel-pump-kit-69302/20770761-P?navigationPath=L1*14932|L2*14986|L3*15378 The loaner fuel pressure tester from Autozone is no longer reading any fuel pressure from the rail. The engine will idle, so I'm guessing the gauge is faulty (how many psi required to idle?), but since late yesterday the motor will essentially only idle. Throttle blips now cause instant sputtering and backfiring. I'm really thinking the fuel pump is on its last legs. The truck has 143k miles and I assume the fuel pump is original. As soon as the new fuel pressure tester arrives I will report back with some readings and updates. As an aside, I was planning on eventually buying a set of reman Bosch 4-hole fuel injectors. Maybe now would be a great time? Thanks Ohm & Hornbrod!! Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 23, 2018 Share Posted April 23, 2018 3 minutes ago, dkenitz said: Hornbrod, is this the Bosch fuel pump kit you are referring to?: https://shop.advanceautoparts.com/p/bosch-electrical-fuel-pump-kit-69302/20770761-P?navigationPath=L1*14932|L2*14986|L3*15378 That's it. Link to comment Share on other sites More sharing options...
dkenitz Posted April 23, 2018 Author Share Posted April 23, 2018 20 minutes ago, saveevryjp1998 said: I just posted about this on mine this morning. Did you clean and trace your driver tail light ground? I literally had exactly the same symptoms, put a loose clean bolt in a factory hole I found back there since the screw was broke off. Instantantly its idle increased, wasnt low rpm, ran normal, and could stomp the peddle with no hesitation. I would follow that wire and check the ground. Sometimes I have found the rear harnesses have been pinched or worn either between unit body and bed or tank and bed. I bet I have found half of my fleet with bare exposed wires in one of those places over the years. The weirdest thing is the wiring on my trucks almost seems to have no ryme or reason on how its routed back there. I really wonder how it was done clean from the factory before people had a chance to screw them up. I am still trying to get the tailgate down so that I can remove the taillight and access that ground. The tailgate handle is gone and I have not been able to fish out the cables. I read that two small slotted screwdrivers could possible be used on the hinges. I hope to tackle that job this week, weather permitting. Link to comment Share on other sites More sharing options...
dkenitz Posted April 24, 2018 Author Share Posted April 24, 2018 Thanks very much for the detailed instructions and explanation! I've done about half of Cruiser's tips so far including the C101 elimination yesterday. I just went outside to try to get the handle mount disconnected. I did see that the cables are attached to the top of the mount, but I was not able to get the mount released. There's a square nut on the studs that I could not break free with heat and a small adjustable wrench. Any idea what size nut that is in the pic or what socket I'll need? I also looked over (as best I could) the latch mechanism. I don't see where I could insert a screwdriver to release the latch. Link to comment Share on other sites More sharing options...
ComancheKid45 Posted April 24, 2018 Share Posted April 24, 2018 Those are the bottom of the handle bolts. You can access them from the other side with a T30 torx socket. Link to comment Share on other sites More sharing options...
dkenitz Posted April 24, 2018 Author Share Posted April 24, 2018 5 hours ago, ComancheKid45 said: Those are the bottom of the handle bolts. You can access them from the other side with a T30 torx socket. Ohh!! The bed has a Duraliner bed-liner and I couldn't see the other side. I was finally able to drop the tailgate and inspected the ground. The screw was rusted and just disintegrated when I put a screwdriver on it. I cut the wire and fixed that ground while also going to the fuel sender harness and putting in a 12g ground wire per Cruiser's tip. The truck would barely start today and would not even hold an idle. I am even more convinced the pump has given up the ghost. The new pump should be here by Thursday and I hope to get it installed by Monday. Link to comment Share on other sites More sharing options...
dkenitz Posted April 25, 2018 Author Share Posted April 25, 2018 Well, the poorer performance issue yesterday was due to me forgetting to plug the MAP sensor back in I drained the tank today and pulled the fuel pump/sender. The strainer was heavily gunked up. Think it looks clogged enough to be the issue? Are there any parts missing on the sender? Does anything attach to that return nipple? The new pump should be here tomorrow. Link to comment Share on other sites More sharing options...
dkenitz Posted April 25, 2018 Author Share Posted April 25, 2018 The oil doesn't look rusty at all and I have a new fuel filter coming tomorrow hopefully. I am all for replacing the fuel tank with a new steel one off Amazon but i want to wait a bit and just get the truck back on the road at this point. Probably will plan on it next oil change. Thanks for the advice!! Link to comment Share on other sites More sharing options...
SVPete Posted April 26, 2018 Share Posted April 26, 2018 Saw your photo and it reminded me of a problem we had with a CUCV during Desert Shield. Paint chips (from the interior of the metal fuel cans) were clogging the filter on the end of the pickup tube. It took us a while to figure that out. Truck ran fine at idle, but when you tried to drive, it would die. We cleaned out the tank and cleaned off the pickup filter and the problem was solved. When the symptoms occurred on another vehicle a few months later, we went straight to the fuel tank and solved the problem. The things you forget and then remember. Man, the bumper number was A122. Link to comment Share on other sites More sharing options...
dkenitz Posted April 26, 2018 Author Share Posted April 26, 2018 Latest update: I just swapped in a fresh fuel pump and fuel filter....... no change. I took advantage of an eBay coupon earlier and ordered a set of reman 4-hole injectors. Any other ideas at this point?? Dustin Link to comment Share on other sites More sharing options...
SVPete Posted April 27, 2018 Share Posted April 27, 2018 Did you clean out the tank? If not, I suggest you look at your pickup filter again just to make sure it isn't clogged up again. Link to comment Share on other sites More sharing options...
dkenitz Posted April 27, 2018 Author Share Posted April 27, 2018 5 hours ago, SVPete said: Did you clean out the tank? If not, I suggest you look at your pickup filter again just to make sure it isn't clogged up again. Good idea. I did not clean out the tank this time and will pull the pump back out and check the strainer. I may try to rig the pump up outside the tank briefly to see if there's a change. Link to comment Share on other sites More sharing options...
dkenitz Posted April 27, 2018 Author Share Posted April 27, 2018 Where does the camshaft position sensor (signal sync generator) plug into the harness? Mine appears to have been disconnected? EDIT: Read up some more and it looks like the Renix motors should run fine with that sensor disconnected. Link to comment Share on other sites More sharing options...
dkenitz Posted April 27, 2018 Author Share Posted April 27, 2018 I pulled, cleaned, and replaced the crankshaft position sensor. The truck ran great for longer than it ever has since I've had it. The symptoms eventually returned but I believe this may be the culprit. The CPS was quite worn and I have a new Mopar CPS on the way. Link to comment Share on other sites More sharing options...
Ωhm Posted April 27, 2018 Share Posted April 27, 2018 Your persistence is going to pay off one day. Link to comment Share on other sites More sharing options...
dkenitz Posted April 27, 2018 Author Share Posted April 27, 2018 39 minutes ago, Ωhm said: Your persistence is going to pay off one day. Hah, thanks Ohm! I sure hope so. So far it has been a fun but frustrating learning curve. Link to comment Share on other sites More sharing options...
cruiser54 Posted April 28, 2018 Share Posted April 28, 2018 17 hours ago, Ωhm said: Your persistence is going to pay off one day. No kidding!!! I'm impressed. Link to comment Share on other sites More sharing options...
coolwind57 Posted April 28, 2018 Share Posted April 28, 2018 Hang in there bro. The solution to my running issues took several weeks but I felt great once I finally got it solved. Link to comment Share on other sites More sharing options...
dkenitz Posted May 1, 2018 Author Share Posted May 1, 2018 On 4/28/2018 at 11:37 PM, saveevryjp1998 said: I thought I read earlier you changed the fuel filter initially. If so or if not it would be a good idea to at least disconnect it and drain it to see what comes out. Especially since your still running that tank and sender without cleaning either first. That is some large rust scaling taking place that could easily clog a fresh filter again as well as a pump filter. You can easily test by extending your fuel sender lines and rollover vent valve tube without having to hang and drop the tank over and over. I think there is a couple of plastic body zip ties to cut or release to give enough slack with hard lines to do this and the electrical plug to sender which will allow you to keep the tank on the ground. I have done this temporarily in the past before. I do not let the gas sit in the tank like that though not sealed. I have always just put a couple gallons in and would pour it back in a can to keep it fresh. It would not have taken much more effort though to remove the 3 8mms? on the cap filler neck I suppose and even put that on so it would be sealed completely and not have to be dumped back and forth. Of course once you plan all this and get setup, you know you will find your problem this last time. Good luck. Yes I did change out the fuel filter at the same time as the pump change. I'm planning on buying a new fuel tank shortly though just to avoid any issues moving forward, no pun intended. I was really amazed at the amount of rust! Thank you for all the support guys!! CPS should get here by the weekend and I will update as soon as I can get it installed. Dustin Link to comment Share on other sites More sharing options...
dkenitz Posted May 3, 2018 Author Share Posted May 3, 2018 It was the CPS sensor!! Truck drove strong on the test route. Thanks everyone for all the help! I have a lot left to do on the truck but I am so happy to be able to drive it.. Link to comment Share on other sites More sharing options...
fiatslug87 Posted May 3, 2018 Share Posted May 3, 2018 Always great to hear another 30 year old MJ is back on the road. Link to comment Share on other sites More sharing options...
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