My friend bought a 1992 jeep Cherokee Laredo, with the 4.0 inline 6 at 262,000 miles. It was sitting for 6 years before we started work on it. It has an automatic transmission, I believe the AW4. It has a brand new Cat, anf we swapped the old fuel injectors for new 4 port because the engine wouldn't run good, then we put in new plugs. It also has new crankshaft position sensor, and drained 3 quarts of transmission fluid and refilled with the correct stuff. It took a bit but the engine started running with the new injectors and was going strong. There is also a new fuel pump and filter. The problem is it has zero power up hill, and the transmission slips. When we try taking off we will give it gas and it just won't move, then it might start to move a bit and we were able to work it up to 55mph by playing with the gas pedal, it would shift to first grab and jet up to 4K RPM. Then shift and just lose all power. If we stop and try to take off it will struggle to move again then just randomly start to go and lose power again. Is the transmission bad? It's fluid looked like bad motor oil when we drained some.

 

Fix Known Problems First.

I'd flush that transmission. It's not difficult, and it's not expensive, so with the bad fluid you had, it's worth a shot. See my sig, #3.

Also, check your fuel pressure. Use a gauge, not your eyeball. Getting a squirt out of the Schrader valve means nothing.

 

Okay we will try that, but we also found out today that the engine it's back firing into the intake. I think the timing is off but I can't figure out how to set it. Any tips on that?

 

Timing isn't adjustable. The PCM does that.

First two things: Test your cam position sensor. It's tucked away inside the distributor. Also your crankshaft position sensor. It's on the bell housing, driver side. Looking at the vehicle from the front, it's at about 2 o'clock, where the bell housing meets the engine. Right where the flywheel lives.

Just to make things fun, both are abbreviated CPS. Some people use CkPS for the crank sensor. I wish that would become universal.

Fair warning - the usual symptom of a bad CkPS is that it jsut will not run. Often shows up as a no-start when already hot (they are heat sensitive). Timing is more likely to be the cam sensor, but check both.

Anyway, lots of videos on both on The Tube. Any video by Bleepin' Jeep is good.

https://www.youtube.com/results?sear...osition+sensor

https://www.youtube.com/results?sear...osition+sensor


Also, on the trans, adjust your kickdown cable, a.k.a. throttle valve cable. Little known outside the Jeep world, it's amazing what kind of trans problems can sometimes be solved by a very simple adjustment. When I did it on one of mine, it took me 10 minutes to clean it up so it would adjust properly (lots of penetrating oil and working it) and about 1 minute to adjust it. The adjustment point (near the throttle body) has to move freely, or the adjustment won't work.

https://www.youtube.com/results?sear...hrottle+cable+



On a 92, it's likely you have multiple problems. It's like peeling an onion. You take off one layer, and now you can see the next one. We're here to help you tackle them one at a time.

 

You said you put a new crank sensor on it, was it a mopar sensor? XJ's can be fickle about sensors, especially crank sensors, they usually prefer mopar sensors.

Just curious, do you know why it was sitting for 6 years? Were there problems when it was parked? (I don't know if there would be anybody who could tell you)

I would recommend doing at least another 2-3 flushes on the transmission, AFTER you get the engine running properly.

Will the engine idle properly?

 

It was parked literally just because the cat fell off, and the bolts to it broke.

 

When my cat fell off, it just climbed back on the fence and fell off again.

Stupid cat.

 

Got the Jeep running good and driving. The fuel pump resister was cause low fuel pressure. The next step is making sure it will stay good.