its a 96 Cherokee Classic, 4L, 4 speed auto, 276000 Km.
Did not start it for a month, battery was low, it cranked and fired, and then died like I shut off the ignition.
Has not started since. It cranks, does not fire or run.
Key trick shows code 12 and 55, no other codes. With battery charging the code 12 went away, but it still cranks and does not fire or run.
Checked the CPS and its okay, think the Camshaft Position sensor is okay, it has 5.14 V input, and shows almost no voltage or 5.13 volt depending on where things stop when you bump the motor over.
I get fuel pressure when I push in the Schrader valve on the fuel rail.
I see spark when I pull a plug, ground it and have someone crank the motor.

 

Based on your description, the 2 most likely items still in play are:


1. Fuel is observed at schrader valve, but actual fuel pressure is not right.
2. IAC (idle air controller) in the throttle body is not opening an allowing air into the system during startup.


#1 Can be check by using a fuel pressure gauge.



#2 can usually be checked by slightly feathering the throttle while starting. If the motor tries to start, this can indicate that the IAC is stuck or failed.

 

Did you do the simple things already like checking there's gas in the tank and fuses, cable connections, etc?

Did you do anything recently or just out of the blue this happened?

 

Well, you nailed it on the first reply!

The Idle Air circuit is the problem. I feathered the gas pedal while trying to start it and away it went. Habits die hard, because you never touch the gas when starting this sucker. It would not idle for about a minute and then the idle works.

I am not sure if that means the motor is bad or sticky, either way, I intend to replace the motor.

Thanks everyone for your advice.

Rob

 

Yep, it means the IAC is sticky and as it warms up it gets less stick (it collects a sooty tar like material on it). You are probably a good candidate for simply cleaning the throttle body and IAC and moving on.

 

Yep. A good cleaning is usually all it takes. Get some throttle body cleaner, some Q-tips, maybe a pipe cleaner or two, and have at it.

Don't use brake cleaner.