JeepcoMJ

Have you looked at the cam sensor? That is in the distributor. I just had a similar issue on my 97/98 conglomoration and it was the cam position sensor... You probably got water in the distributor and fried that sensor.

Maiden voyage went well today.

She runs great, drives great. Maiden voyage today went well..

Spark test with plug to ground, and inli ne tester. Injectors weren't working either...tested with home made 12v noid light. Jpdocdave suggested distributor. I swapped the sensor and that was it. I normally don't ask as many questions as I have been lately...I just don't have time to be stumped right now lol.

97 xj 4.0 will not start. I just converted the jeep to ax15 with a conplete 98 parts vehicle...this was a complete wiring and accessories swap. The cps tested bad so I swapped it and still no difference. Grr what a pita, anyone have any ideas?

Side note. I've owned 2 mj's with 2.8's and one xj. The xj had a bad motor at 90k, and the parts mj had 200k. The 3800 had 60k and was on it's second motor (reman late model with better oil passages). By 66k that 2.8 was dead When the one mj went to scrap I removed all fuids, dropped a brick on the gas pedal, and let it run til it seized. It started before it was picked up next day. It's a horse a piece, but 2 out of 3 left me hating them. Replaced it with a buick 3800 series 2 and only regretted blowing ax5's after that

Went against my opinion and replaced the o2 sensor with a brand new one. Like I thought, not the issue. Knock sensor is broken, tho.

Don't quote me on this, but I've heard from many sources that the new motor has to be of newer year than the vehicle in order to pass safety inspections.

Lol. I just assumed that that it would be assumed that I'd do that, too

Luke, you just proved that the 4.0 gets more kmpg than the 2.8. They get crappy mileage because gm screwed up the design, and amc decided on carbed, and the government stuck their noses where it didn't belong and required emissions BS that robbed what little power the 2.8 had anyways

ruling out fuel pressure as the issue. my pressure gauge apparently reads low. 89eliminator's truck shows the same identical readings as this one. so. I'm going to just swap the fuel rail for $#!&s and giggles, and look at the plugs, wires, and cylinders better. if none of this works, I'm telling the room mate to scrap it or put a new motor in it. I'm not doing anything serious on a POS truck, though.

mine literally couldn't get out of it's own way. 5th gear was worthless, even with stock tires. i got a max of 13mpg with factory carb, 15mpg with the edelbrock adapter and 2bbl carb. I will NEVER drive another 2.8 further than it takes to get to my house and tear it out. what a piece of $#!&, there is zero power, zero mileage, and the factory design sucked for it.

the detente's on the side of the shifter that return it to center probably went bad. they're easy to replace and don't require disassembly of the trans.

I should have said "different pump". I took the pump and sender out of another 4.0/swb mj that had no running issues and had roughly 30psi, and put it in the truck. I don't spend money on parts if I can avoid it lol.

sorry, i saw last post as wahoo. just woke up, all over the place and my head isn't screwed on yet.

thanks Wahoo. and you probably are smarter than me. I accidently deleted the part about it having a new fuel pump, sock, hoses from pump to hard lines, vent lines, gas tank, and fuel filter. so I've ruled those out. I think the only thing it could be, now, is the fuel pressure regulator...thinnking of just swapping the whole fuel rail and injectors.

it's the 1/8" steel that's mounted to the body. he reinforced everything except that...I've torn factory bumper brackets apart right off the frame on the back.

Oh, and the cat isn't clogged...there isn't one.

Working on my room mate's 87 mj. 4.0 aw4 4x4. It wouldn't rev past 3600. I initially thought cps, or ecu. Swapped both to no avail. New cps actually makes it not rev past 3000. New distributor, properly indexed...no improvement. I've swapped the throttle body, map sensor, ignition coil, and the sensor on the intake manifold with no improvement. Fuel pressure at the rail is max 20psi with key on, 10 when running. Replaced all vacuum lines because they needed replacing, and I figured it couldn't hurt. Compression is 120, so it's not a timing issue. This truck was subject to the cps recall and has had the c101 bypass done, where the wires go directly to the ecu rather than through the loom. Voltage test shows 0 ohms on both wires, so that's not the issue. My last bet is the fuel pressure regulator. That fuel pressure is way too low, but I don't know what it's supposed to run at off the top of my head. The truck revs just fine from idle to 3k, then bounces like it's on a rev limiter. Last thing is that the exhaust manifold is cracked pretty bad. The 02 sensor is junk. But that cannot be the cause of the issue...the truck should rev fine in bypass on the ecu until it's warmed up, at least. Anyone smarter than me? ...cause this has got me stumped. Thanks, Pat

put a new gas tank in the room mate's jeep, and redid the vacuum lines and PCV lines.

lol. thanks for chiming in, pops!

Why do I need side protection when I don't have rear lower quarter panels and the upper corners of the bed are armored? What a useless comment? :dunno: I don't see any TJ's out there with corner guards that run wrap around bumpers as well and their corner armour is less thick than mine..... And the mounts are too weak for what? To pull a yacht? :shake: My quarters are cut and I've come awful close to crushing my quarters landing on rocks. The mounts to the body are too weak for even remedial recovery

My dad averages 32mpg mixed driving, and has under 2000$ invested in his renault in the roughly 12 years he's had it....and that includes purchase price and maintenance. Timing belt idk where to get it...my dad got one with the truck. Try napa or bumper to bumper, or a winnebego dealer

there is zero side protection there....and those stock mounts are too weak.

It has it's own bell hosing, and the ax5 for it has a 2.1 specific input shaft in it, so if ur trans ever goes, you have to gut the new one and swap inputs. Nothing just swaps in.