Dickinson County Comanche

IMG_9194.MOV

We’re talking a very low rpm here too, it’ll lose spark when the engine high-idles to warm up.

New cap and rotor have done nothing. I tested the good ICM and coil from my 89 4.0 and it did nothing. It has very hit-or-miss spark at anything above basically idle. I’ve put in 2 CPS’s and neither of them have improved it any. I’m genuinely at a loss here. Distributor is in time, good plug wires, and all of the plugs have been gapped (minus cylinder 1, but I can verify that it’s firing) to spec. Distributor doesn’t have a major amount of play, and is on the correct tooth of the cam.

Hopefully this is it. I threw a spark tester on it and it loses spark then misfires, it doesn’t do it however when it’s idling so hopefully it’s just the cap and rotor being worn out.

The cap and rotor were kinda worn, I have new ones coming in tomorrow

EGR is bad but it was stuck closed.

They looked good although maybe just a skosh toward the lean side.

It definitely could. I’ll have to check it in the morning and see.

I’ve checked the MAP with another I know is good and it’s made no difference. Coolant was good and it had no extra pressure or exhaust smell. Vac lines have been checked and I do not hear any leaking like I would. I haven’t adjusted the tps but I did plug in a good one on a TB I have laying around and it didn’t have any difference.

I’m at a loss here, I recently acquired a 2.5L 86’ for cheap that hadn’t run in a while and was missing its transmission. I’m happy to say it runs and drives now, but like absolute garbage. It’ll sit and idle, smooth, all day long. But if you try and rev it (above ~1000rpm or so) it will sputter and begin to backfire through the intake. It won’t die though, although the popping does get noticeably more stronger. I indexed the distributor 2 teeth back and it allowed a little throttle to be applied, but it’ll backfire through the exhaust instead of the intake. Here’s what I’ve checked so far: - Distributor timing - Compression ( #1 I didn’t check because it’s hidden behind the A/C compressor, #2 135psi, #3 140psi, #4 135psi) -CPS voltage -exhaust blockage (ran bad with exhaust not hooked up) I haven’t tested fuel pressure but I think it would be ok. New fuel pump and fuel filter were just put in so maybe a blockage in the line? I also have very little vacuum at idle, there’s some for the brake booster but none anywhere else and none of the dash vents work. It also does have a “high altitude” CPS in it for some reason so would that maybe cause it? I have an extra CPS for a 4.0 that I can toss in if it’ll work or not.

Went out and checked the transmission behind the 2.8 yesterday and I found this! So glad it has the CPS port, I was getting worried. Although I wonder if Chrysler could have made the hole cut look any worse lol.

Built on my Birthday! A few years before my birthday, that is.

I looked up part numbers on Rockauto and they were compatible. I’ve had pretty good luck with Rockauto so I trust it.

It’s from a truck built in 85 so it would have come with the A904 originally. Luckily the 2.8 shares the same basic driveline configuration as the 2.5 in terms of lengths and such.

Yes, it has the little lattice for the CPS. It does have the kickdown and shift linkage installed already, but I wasn’t sure if the actual trans side would work or not.

Extra pictures:

I do have the flex plate already. Got lucky there

Hello all, I just picked up a 2.5 truck with no transmission to swap in the transmission and transfer case from my 2.8 in and I was curious if everything worked. I know shafts, crossmembers, starter, and torque converter swap over just fine, but I’m curious if the little things will, such as TV cable, shift selector, and CPS hole will as well. Any help is appreciated.

About 150-250rpm

Yes. I don’t have a/c so it’s not the trigger for the electric fan.

I’m running a new temp sensor, but it’s in the place where the HO one goes because I couldn’t get the plug out of the block. Every IAC I have has been cleaned, and the spot in the TB where the IAC goes has been cleaned. I haven’t unplugged it to check but based on the previous issues I’ve had I’m going to go out on a limb and say it would probably idle consistent with it unplugged.

Warm. Cold sits and idles steady. It’ll sit at warm at ~1000rpm then bump down to 850-900 momentarily, then go back up. It’s a consistent idle pattern, like the IAC is too slow going in and out. When it idles down like it should, it’ll go from 750 down to like 500 then back up.

Update: changed the O2 sensor and Knock sensor and it helped the idle. It’ll actually idle down now but it takes a little bit. Now the idle speed is correct but it fluctuates up and down now. I have a feeling it’s the IAC.

This truck will live on, I am going to use the transmission and rest of the driveline in a 2.5 truck I got. I’ll create a thread on it soon.

1986 Jeep Comanche 2.5, (Missing, but should be A904, NP207), Dana 30, Dana 35 LWB Build date sticker is faded, can’t make it out, but I’m guessing 10/11/12 of 1985. NC Kansas Hopefully gonna get back on the road High trim X. 2.5L with cruise control, tilt and a nice red interior. A/C, 4x4, automatic, but no sliding glass or even a tape deck. Oddly packaged. Me. Just bought her.