bigmistake

I will order a new pressure regulator, and I'm guessing I should go ahead and get a pump as well. I should have clamped both lines before shutting off the engine to see if it held pressure... but I can't imagine it is leaking all of that pressure immediately through fuel injectors. Prices are all over the place for regulators. Is there a brand I should look for or avoid? Cheap Average Expensive And for the pump, I've read I should get a Bosch - the part that keeps coming up as fitting has lots of reviews saying it doesn't fit. Does anyone have a part number I should be looking for? Thanks for all of the help! I will post results when I get everything hooked up.

Thanks! I will do that next. @HOrnbrod - I guess I'm not pulling a vacuum. I clamped the line and no change.

Nope! I'm kind of learning all of this as I go... I will go try that while I still have the gauge. Thanks! How should I go about checking the engine vacuum? I don't currently have any check engine lights on, but I'm guessing the code is still valid?

It is definitely a '91. So, I pulled the vacuum hose and the pressure didn't change at all. I guess the pressure regulator is bad, too?

I replaced the fuel filter a week ago. I thought I disconnected it and didn't see a change... I will double check I disconnected the correct hose tomorrow when I get back under the hood. I found a pretty good video of lots of debugging I can do, so I will start working my way through the list.

Hey everyone, I'm still plugging away at my MJ. It is a 91, 2.5 I am pretty sure I've got a problem with my fuel pump, but I want to get the wisdom and advice of everybody here. I rented a fuel pressure test gauge and threw it on the fuel rail. Here is a quick video (audio is kind of garbage, might want to mute or headphones off): It looks like I'm only getting up to 15 while the engine is running, then it bleeds off immediately. Am I right in thinking it is the fuel pump? What else should I look into? Thanks!

I was thinking about it and realized I haven't checked codes in a while. I got: 51O2 detects lean mixture.Check sensor and circuit and for vacuum leaks. 33Air conditioning clutch relay.Wiring to A/C clutch fault. --------- The AC compressor kicks on and off over and over... so I am guessing that is the reason for the 33!

Replaced water pump, flushed coolant, replaced control arm bushings, replaced distributor cap and rotor, new fuel filter, and recharged the AC. I took it for a quick drive to gas up... Still not running right. It takes a lot of cranks to get started, then has to sit for a while or it bogs down when I give it gas. Once I start driving, I almost always get misfires for the first 5 minutes of driving along with sluggish acceleration. Maybe my fuel pump is on its way out?

Checked, no new codes (12-55).

Thanks Hornbrod - I didn't even think to check codes since the CEL didn't come on. I will do that when I get home!

I replaced spark plugs and wires this week. It immediately drove better than it had been. Went to the store, came back out, and it started misfiring again. I let it sit for a while, started it up, and it was okay again. I'm going to slowly work through debugging the ignition system. I'm going to take a look at the distributor cap and rotor next.

Bumping! I might have to settle for a ranger or s10 topper.

I know this is a shot in the dark, but I'm looking for a topper for my short bed in Texas. I'd love to find one like this: Let me know if you've got anything! Thanks!

No pictures for this post because I was almost immediately covered in grime... But I put on new shocks yesterday! I managed to pick up some JK Sahara shocks and the parts needed to mount them, following jerpderp's DIY thread. The highlight of installing these was getting to see how bad the old shocks were. The rear passenger shock I could compress with my hands, and when I was cleaning up 30 minutes later it was still completely compressed! I didn't take the truck out afterwards, so I can't comment on the ride quality - but it is definitely going to be an improvement. I had a lot of trouble pressing the new bushings into the shocks, but I remembered a solution I saw somewhere that really helped - I used a hose clamp to compress one side of the bushing, then pressed the bushing in using a vice. I tried a ton of stuff before that, this just happened to be the one that clicked best for me. Now, the not so great: I drove A LOT around town with a friend so we could hear the truck get flaky with accelerating... For the first 15 miles or so, the truck never missed a beat. After it had been running a while, it started failing to accelerate more frequently. When we got home, I parked it for a few minutes to re-arrange cars before putting it in the garage, and it wouldn't start. When I finally did start it, the idle was ROUGH and it kind of felt like it wasn't firing on all cylinders - really chugging and lopsided. I turned it off and on a few more times and eventually I was able to get it to start and sound normal, but then it wanted to die on idle, so I had to keep my foot on the pedal. Not sure what that was about. More investigating is in my future...

Thanks for the ideas. I will see if I can find anything in the tailpipe... and otherwise just keep driving.

I have a 91, 2.5l HO that has been sitting for a couple years. I recently swapped out oil, coolant, and gas, and drove around the neighborhood. The truck runs great and sounds great... but several times when in 4th gear and around 2100 RPMs, the motor stopped revving and sounded muffled. Eventually, a CLUNK happened under the pedal (audible sound from the engine bay that I think I could feel through the pedal... but that might have been my imagination) and it would rev above 2100. This happened a couple of times in my short drive. It never happened in 1st - 3rd... but I also haven't driven it much. Any ideas on what it could be? Thanks!

Thanks Minuit! I have been watching videos on flushing the system - yours sounds like the simplest. I will take a look at the blend door - definitely sounds like it could be the problem. On the AC - I know the compressor isn't spinning. I swapped relays to see if that would do anything, but it still didn't work. I need to get a multimeter so I can see if it is getting any power. I think I also read that if there is no freon in the system it won't spin...

Progress! I replaced my valve cover gasket, hooked up my vacuum canister, and did my oil change. So, as I've mentioned, this is my first time working on cars... I thought the valve gasket would be pretty straightforward for a first project (and it goes hand in hand with the oil change, so worked out). While removing everything touching the cover, I bumped the heater hoses. The heater control valve immediately exploded! Coolant went everywhere and I was left staring at a mess. After going through the parts manual I was finally able to figure out what the part was (I had no idea). A quick search on the forums let me know that everyone universally despises that part and that I should just delete it. SO - I no longer have the heater control valve! There was a little white wire/line connected to it that I'm unsure what to do with... I just left it dangling. If anyone knows what I should do with it, let me know! I may have to post in the other subforum. I had also noticed my coolant was low before this, so I rented a pressure tester. Turns out my cap was bad so I replaced that. I haven't flushed the coolant, but I should probably do that since the truck has been sitting (I'm not having overheating problems or anything, just feel like it would be a smart move). One thing I noticed from removing the control valve is that my truck blows hot air now. My AC doesn't work (no clue why), so I'm guessing since no cold air is blowing it is opting for hot air. It might not seem like much, but that is the most work I've ever done on a vehicle, so it is a good start! I took the truck for a spin and let it idle in the driveway to check for leaks. All looks good so far.

Not much in the way of changes since I've had it. This weekend I removed all of the decals, took off most of the front end and put it back together. There is some crookedness from a past wreck that I'm wanting to correct. It was also a nice excuse to wrench on a vehicle for basically the first time. I had a vacuum canister that the previous owner had left in the cab. He said that the previous owner before him had purchased it to fix his AC... So, I tracked down where it should go and found a hard plastic line with duct tape on the end. I'm going to pick up some hose and get things connected. There is also a slow oil leak on the valve cover. I searched around town and nobody had a replacement gasket for the 2.5l, so I've got one ordered. Next up: valve cover gasket, vacuum canister, fluid change... then a LOT of hauling things out of my yard and garage to clear up some space. And trouble shooting why the AC won't get cold (I know the compressor won't turn on, but I haven't really dug in yet). Future plans: I found a 4x4 donor with matching gear ratios! The problem is, transfer case is missing off of the transmission. I'm debating finding an ax15 + transfer case to swap over to... based on my research, that would require a bellhousing, pilot bushing, and clutch disc to get it to mate up. We will see.

Thanks for the reply, Keyav. I didn't even think to measure the inner fenders to see how close they were. I will do that today and see if there is what happened. Good info on the gaps. I can push them out a little bit. The firewall gap is even with the hood. The ridges in the hood aren't lined up perfectly, but overall it seems pretty close - I will align those and see what happens. The passenger side is an aftermarket fender. Good info on the bumper mount. I was looking at aftermarket bumpers last night, and it looks like a lot of them come with plates that go over that area - so I might just pound it out for now as a temp fix and ultimately do a better fix when I'm upgrading.

Today was my first day to have time to tear into my MJ. I started by trying to figure out what exactly is crooked/bent on the front end. It is obvious there was a collision of some kind - the area the bumper is mounted is REALLY bent. Any thoughts on straightening it? Pics of the bumper mount area: The other side for comparison: From the front: So, after looking at that for a while, I decided to pull off the front fenders. There has been some crookedness there, so I wanted to see if I could fix it. I ended up finding a lot more weird stuff. Driver's side: I was able to get the fenders flush with the front clip (I need to replace both fenders... one is a weird aftermarket fender that doesn't really line up with anything or have the same setup that the maroon one has). But the hood seems to be crooked. Hood Passenger Side: Hood Driver Side: Overall showing how the gap grows: Alright, photo dump done. Any thoughts on how I should tackle this? I'm thinking picking up some new fenders and maybe front clip since all of that seems to be a mismatched mess. I'd love to get the bumper mount sorted out. Should I just beat on it with a hammer? Heat it up with a torch and then beat on it/pull on it? And for the hood... should I loosen up the bolts near the cab and shimmy it over until it looks more aligned? Or is it a more serious issue from the front end collision? Thanks for any help/insights! I would have never tackled all this stuff without this site... and I'm having a blast!

Thanks! This post has a ton of excellent info. You are awesome!

I was going to start a new thread, but I think piggy-backing on this one might work... What considerations need to go into picking parts from multiple vehicles when planning for a 4wd swap, or when thinking about updating/replacing components? Will front axles and drive shafts from all years work with one another? For example, if I buy a front axle from an 89, would that bolt straight up to an 01 drive shaft? And would all front drive shafts mount to all transfer cases? I ask because I often see pieces of what I need, but almost never _everything_ I need. So, what parts are safe to pull solo, and which would be best to get all at once? Transmission + transfer case is obvious to me, but everything else gets confusing. (I spent hours reading through spline counts for different components but could never figure out how everything relates to one another).

Thanks for all the responses! And good info on the wood blocks + stands.

What is everyone using and what do they like? I'm shopping for my first set. Thanks!