bucketheadben

Hey guys. My 90 XJ 4.0 Auto has had a long starting problem since I've owned(couple of months.) I think it has something to do with the pump or pressure regulator, but I'm uncertain because priming it doesn't help the long start. It will take about 5 secs until the engine spins over. The start time will be cut to about 3 secs if it was running recently and I try to start it up. Today for the first time it stalled out on me in traffic. Once at a red light and twice decelerating around MPH. It would run rough right before dieing and it would start up like normal afterwords. Once i got it in the driveway i started it up and would idle fine, then i restarted it and it died immediately twice and on the third try it was fine and took it around the neighborhood with no problems. So do you guys think this is a fuel issue or could it be a sensor(TPS,CPS,IAC?) I'm going to clean the TB and IAC while I wait for some input. Thanks in advance for any help. Ben

Here they are. Half of my 99 Cheromanche and the future DD. Image Not Found Image Not Found

Hey guys, It's been awhile since i updated this thread. I've been occupied with another project. I'm up to 4 jeeps now. :D I just picked up a 2 door 90 XJ 4.0/aw4/242 for $200. The XJ need a new engine, so i swapped it with the MJ's running 4.0. So now the XJ is just about driveable. Here comes the good news. Once the 90XJ is driving i'll be retiring my 99 XJ and making a 99MJ out of the 2 jeeps. I'm retireing the 99XJ due to frame damage it has received from a past wreck. I'll be swapping in just about everything i can from the xj. I'll post some pics of the 90 and 99xj's soon. Ben

It was the TPS, however, I didn't need to replace it. I decided to pull it off and check the resistance between the input and output while moving the throttle. It was operating correctly, the resistance would drop as i opened the TB. It turns out the TPS on the TB that I got from my donor engin wasn't installed right. The lever on the TB wasn't moving the lever on the TPS. That's why my output at idle and WOT were the same, the TPS didn't know the TB was opening. I love the problems that you don't have to spend money on to fix. Thanks to everyone who helped me figure this out. Ben

That was my first guess. I replaced fuel filter and tryed bypassing the fuel pump resister but it still acts the same. It is harder to start once it dies. It will spin over and sputter for alittle while then it will run fine. Thanks for the ideas, keep um comming please. Ben

Nope, same one from the MJ Mas and O2 are connected. I'll check all of my vac lines and intake manifold.

Hey guys, I've recently swapped a perfectly running engine for my 88 MJ(manual) to my 90 XJ(Auto) and now the xj is not running right. I only swapped the eng, belt accesories, intake, fuel rail and injectors. I reused the TB and all wiring from the 90 XJ. The XJ will take about 3 sec to start and then idle at 1000rpms then drop down to 700rpms. It can sit and idle with no problems. Once it hit the gas it will rev up and come back down as i let my foot off the gas, but it will drop down to a lower rpm and sputter. The higher i rev it the lower it will drop down afterwards and sometimes die. I can press the gas and keep it going. The xj now has new plugs, wires, cap, rotor button, cat+muffler. I've cleaned the TB, IAC, check and adjusted the TPS. 4.7in, 4.2out Any suggestions? Thanks Ben

Sweet. Eventualy I will have a 99 MJ also. My plan is to swap everything out of it into the MJ. Drivetrain, interior, doors, front clip. Everything possible. The 99XJ is my DD right now but it has some frame damage front and rear. Once i find another DD i'll begin the swap. Thanks for all the great info. Ben

Yep. They bolted right up Would the newer doors bolt up?

If they are not necessary for frame strength then I'll just lay the sheet metal over them. I'm sure it will be easier to build risers than new fram caps. Thanks ben

He had 35" TSL's but when he sold it to me, it came with 4 donuts. Plenty of flexing room. :D

I've got a question for anyone who has repaird their floors. Notice how I have cut off most of the metal that caps off the frame rails? Should i weld some thicker steel on top of them or will sheet metal work? I know that xj's don't have that cap on them so does the mj need it? Thanks guys Ben

Well, as promised, Here she is. Image Not Found 97+grill in the future Image Not Found SOA in the rear Image Not Found The better of the 2 sides Image Not Found Floorless Image Not Found

Hi everyone. It's good to own a MJ again. I saved it from the crusher about a month ago. A friend of a friend was going to take it across the scales, so I offered some money and he took it. My wife couldn't believe her eyes when I pulled up with it on the trailer. It's named the POS around the house thanks to her. :D She loves my YJ but hates the MJ. I think she'll change her mind once it starts to show some progress. Anyways let's talk about the truck. It's an 88 SB with the 4.0, Peguot(no reverse), 4x4 12x,xxx miles. When i bought it the front axle shafts were busted and I could see just about all the internals of the t-case by peeking under the truck. It also had a real rough idle and a bad exhaust leak. I swapped in a Junkyard D30 with factory 4.10s, a spare np231 that I had laying around, a new EGR valve and exhaust gasket. Now it runs great but it's still not ready for the road/trails. I need to swap trannys. I'm looking for and ax-15 to replace my Peguot. I need to repair the rusty floorboards. (Halfway done) :cheers: I need to fix the getto rigged spring over that the PO did. He bolted in a xj 8.25 without welding on new perches. But thats not the worst part. For the front lift, he welded 2 coil spring together :eek: But don't worry I did away with the front when i swapped the front-end. It's sitting stock in the front with SOA in the back. It's quite a sight to see. POS is a real deserving name right now. I'll try to post some pics later. Ben