Dead jeep

[piecesnparts]

I have a 96 grand cherokee with a v8 I drove to work and everything was good. I went to start again for lunch and its dead.

it cranks over strong, so its not a dead battery or alternator.
On the fuel rail I press the release and it shoots out fuel, and I can hear the fuel pump running. I unpluged the wire from the coil to the distributer and put a spark plug in it and its not getting any spark.

I wasnt sure if this is a valid test on a newer vehicle (works great on my old cj)
looking for answers, it might be my coil or any other thing, also if you have easy ways to test the parts that you sespect, any help is appriciated.

 

[Milner]

CPS, Crank Position Sensor....Only replace with Factory part!!!!
CPS is always the first thing to check in a Jeep FI motor. If you replace and it is not the problem, then you have a spare that you WILL need sooner or later

 

[piecesnparts]

I dont like getting 100 part to test, but since I know nothing about newer vehicles I will try it.
I will probably do it tomorrow and let you know how it goes, thanks for the quick reply.

 

[wally]

2x on the cps.

 

[lewis]

i had one of these and it would do this to me every three months because the rotor in the cap would get to hot and get fouled up so I would replace it or just clean the contacts and it would be fine for a few more months.

 

[piecesnparts]

I grabed a cps and I will look at the rotor tomorrow when I change the cps.
Thanks guys

 

[Fuller]

i had one of these and it would do this to me every three months because the rotor in the cap would get to hot and get fouled up so I would replace it or just clean the contacts and it would be fine for a few more months.

that wouldn't be the problem if he is not getting any spark from the coil.

 

[1993yj]

I would try replacing the coil. I have had that problem before. And make sure you get one from the factory for this too. I got an aftermarket one once, and it lasted a week.

 

[piecesnparts]

Ok lots have been done since the last post. The crankshaft sensor the coil and the camshaft sensor have all been replaced or verified as good, so I started to look at the wiring and I think it might be the PCM. When I stick a volt meter on the connections to the camshaft sensor and the crankshaft sensor and crank instead of reading 5.0 volts and 0 volts I get 2.5 and 0 and everywhere in between. At first I thought the harness, but its strange that both of the sensors are not reading correctly. Is there any way to test a PCM in or out of the vehicle, or any other people have the same experiance, I cant afford to get a new one if its not the problem.


Any help is appriciated.

 

[piecesnparts]

oh and the cap and everything is very clean and looks good. Also tried to swap the asd relay and no go, the other weird thing that leads me to think PCM is I get no check engine light when trying to start( I used to) and when I hook up a OBDII scanner I get unable to link.

 

[Bart]

I seriously doubt it's the PCM, but stranger things have happened.

 

[piecesnparts]

I seriously doubt it's the PCM, but stranger things have happened.

Bart, any thoughts on what it could be, I am just trying to figure it out.

 

[Bart]

Well, I had a similar problem on a 90 XJ I used to have. I replaced the CPS, TPS, coil, cap and rotor, plugs.... Finally went back to the COS and hard wired it, bypassing the plug. Never had a problem after that. I know it's a shot in the dark, but it's a cheap fix. It's chasing straws at this stage. Of course mine was a 4.0, not the V8.