Starting Issue

[danwoz]

Hi,

I have what to me seems to be a really strange problem that I am unable to find similar diagnosis anywhere, even Jeep experts have had a look at it, and everyone has drawn a blank

I am wondering if this could be related to the BCM, does anyone know where this is located on a right hand drive Jeep? Security System, and location of the module?

96 Jeep Grand Cherokee.

So the problem is this. I had an over charging issue which was fixed with new alternator and now the problem with the starting got worse and worse over time, and now I don't believe it is even possible to start it. If I unlocked the car and tried to turn the key it would light all the cluster except the check engine light, every time this occurred I knew the car would not fire, so turning the key off one click locking and unlocking the car and trying again the check engine light would come on then go out and the car would start fine, once the car was normal running temp for a while it would always unlock and start up first time as it should do, if the car was off for a longer period of time then the original problem would happen.

This issue got worse and worse where it would require attempts of unlocking turning key, no check engine, turn key back one turn, lock and unlock, turn key to point just before turning to start. I would have to do this mentioned process over and over again until the check engine light came on and went out again. Even with the issues as I explained here at times 30 times doing this in the final days before I took the car in, once the car was up to full running temp it would always unlock and start first time.

Most frustrating thing is that there is no codes to read.

So the diagnosis shows that when the check engine light does not come on there is also no power at the ASD relay (tested and listening for relay when unplugging and plugging back in), which then nothing at the injectors or coil.

With the car running I have been quite rough with all the loom cables into the PCM and main engine relay box hoping the car would stall but never had an issue with that.

Checked all the fuses, cleaned the contacts and applied a little electrical paste all the ones related to ignition and running of the vehicle
PCM has been replaced as well as a module behind where the key is inserted in the steering column from another running car that I had.

The problem here typically is the opposite to other reported issues that I have been able to find, where the car starts no problem then stops when it gets hot, or just wont start, typically was a short, loose wire, one youtube diagnosis one I saw was wires shorting on the header pipes to the oxygen sensor. All of which don't really fit with the issue I describe.

I have two new oxygen sensors in the car, should I try the old ones back in or is it like to be unrelated?

Has anyone had the same issue and resolved it please???

[bodgie]

Interesting problem you have, not sure many will be able to help here if I'm honest as the ZJ isn't super popular here.

I'd try as much simple stuff as possible, I don't' think the O2 sensors would stop it starting as it should just run some default values and still run.

If it does occasionally start the problem probably isn't too bad. You just need to work out what it is.

Looks like you can obtain a service manual from here:

https://www.manualslib.com/manual/82...-Cherokee.html

I'd have a read

[danwoz]

Thanks so much for your reply, this was a last ditched effort in a hope someone might have had a similar issue. Thanks for the manual link, I will take a look at it and see how to compares to the ones i have.

[Doctorbob]

Wow Danwoz,

This is the exact same ignition problem i have been trying to fix for 12 months now (including 3 hours this morning). I am interested to hear the responses you get. I cant even get the check engine light to illuminate at all now and only have dash power to oil pressure gauge, Is that the same with you?.

Rob

[saboyce2000@yahoo.com]

Hello, I am not sure if any one has found any fixes for this issue but my jeep xj 1996 sport has been in a Chrysler garage for 6 months now without resolution to the same starting issue. I was advised it was the BCMa Body Control Module and Master Window Switch . I have now been advised that the part can not be sourced . If anyone can offer any advised on where to source the part or recommend a garage or mechanic I could try i would be so greatful . I seem to be paying for the jeep to be towed to garages that have no idea or can not fix the issue.

I did contact a Canadian parts company and after explaining the issue they could understand why the garage was replacing either part but could not electorate unless the mechanic called them directly. Which unfortunately that did not happen.

Thank you in advance.
Sarah

[MuzzaWA]

B&T Jeep Sales is a wrecker in Malaga (WA) that specialises in Jeep, last time I was there they had a heap of WG's.

No web page as such, just FB:
https://www.facebook.com/bandtjeepsales/