MackJartel

My 1995 Cherokee Grand 5.2 ZJ wont start. I was driving and it died all of a sudden the check engine came on and was flickering. There was fuel pressure and It kind of started but died. I had it towed to a mechanic, The next day I checked for pressure up front and there was none and the pump had no sound from the back. The mechanic hooked it up to his scanner and couldn't locate the main computer however he told me there was no fuel or spark. So now Ive towed it to the dealership and i know they are going to rape me. My mechanic says its either the computer or the alarm system. The alarm has always been wonky...

wingless

Welcome to the forum.

The first generation ZJ is a great vehicle. One reason is that it is possible for the owner to resolve 100% of the problems.

Two essential tools are the Factory Service Manual (FSM) and a fuel pressure gauge.

The factory alarm system could inhibit the engine from running, but that should be accompanied by the lamps flashing.

The scan OBD I works best w/ the Mopar DRB II scan tool. I had horrible results w/ quality aftermarket scan tools and excellent results w/ the Mopar tool.

MackJartel

I replaced the ECM 2 years ago with a rebuilt one. Im thinking the alarm too. Ill see what the dealership says..Hopefully I can bypass the alarm its useless anyways...

MackJartel

Ofcourse the dealership ripped me off. This is my invoice....
Would the alarm be the reason that the scanner cant reach the computer?

MackJartel

Does anybody know what this module is? its located in the kick panel on the drivers side.

wingless

Again, the ZJ is a great vehicle because it is possible for the owner to perform 100% of the repairs w/o EVER having to visit the dealership.

If the plan is to NOT turn your own wrenches, then sell the vehicle because there is NOT enough time or money that can be thrown at the car to be happy w/ the result.

The module w/ the failed components is the Instrument Panel Dimming / DRL Module. That failure is common. Some have performed repairs w/ acceptable results.

MackJartel

I want to keep it! I love working on it but I only have a month to get this going. Now that I know what that part is its not the reason its not starting... Do you think the PCM needs to be replaced?

wingless

The alarm instructs the PCM to NOT permit the engine to run.

When the alarm is active, the exterior lamps flash, the horn sounds and the dash security lamp flashes. Does the vehicle have any or all of those symptoms?

The vehicle requires the Mopar DRB II scan tool. I have had unacceptable results w/ every other scan tool.

My guess is that the PCM will communicate fault codes, even with an active alarm condition.

wingless

The reason for not running has not yet been determined.

Has every single fuse been verified good?

Is there fuel pressure? Does the fuel pump have voltage?

This reply shows my PCM capacitor replacement.

dave1123

IDK if this helps, but I had problems with my scanner not communicating with the computer and all it was was dirty connections in the diagnostic plug. I sprayed it with contact cleaner and made sure no pins were bent, then it worked.

MackJartel

Is the PCM ECM together in one unit? I had a this computer replaced 2 years ago. this is what it looks like. This is the part number i used: ECM = R6026790

wingless

The parts manual has over a dozen Single Board Engine Computers listed. The correct P/N is not clear to me from that document for your vehicle.

wingless

Here is a partial of the 93-95 Parts Manual page, showing the numbers.

MackJartel

I pulled the computer. Pretty much impossible to see if anything is wrong with it?
Should I look for somebody to have it tested?

wingless

The visual inspection shows the electrical connector is very dirty.

That is probably not causing the fault, but that connector should be clean.

The PCM has had the capacitor rework, so that is good.