2002 Pontiac Montana Intermittent No Start

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Rustynice

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once every few days the van will not start randomly no matter how long you crank it. However when this is occuring there is no injector pulse Fuel pressure is good and there is both spark and compression. I have changed prior to this fuel pump, pressure regulator, ICM. Here is the kicker that's stumps me When this occurs If you run it on an alternate fuel source for a few minutes it will start, run, and stay running. then be good for a few days. Any ideas? :confused:
 
check the crank shaft position sensor and the wire harness connected to it
 
Couldn't that have been ruled out as it has spark? or is start-up injector pulse controlled by crank sensor?
 
I'm not sure we are on the same page I have spark but NO injector pulse.

What controls injector pulse on start-up?


Does the Crank sensor control start up spark and Injection?

Am I missing something?


/edit I appreciate your responses.
 
Last edited:
Hi!
Check the fuel pressure. If the pressure is in the range of 50-60 psi, then it looks like you do not get the momentum jets from ECM. ECM is dependent on a signal from the ignition control module to fire the injector. This is most likely a problem in the ignition module. If the module is running, inspect the wiring harness at the pcm, under the air filter box. It is possible the harness is chapped and shorting where it exits the air filter box or down on the transmission. If the harness looks okay, make sure the INJ fuse in the underhood fuse panel is good. Check to see if there is power on this fuse with the key on.
Good luck to you
 
Fuel pressure is 55lbs cranking, I have replaced the ICM, I will look at the wiring harness under the air box and check for shorts and burns, The injector fuse is good as i have checked it and it is intermittent.
 
I would look at your camshaft sensor located on the right top side of the engine if your sitting in the vehicle.you can follow the wire harness to it along the front rocker cover,it,s a three wire pin connecter.i have personally had issues with a no start and was a faulty cam sensor as it controls fuel timing.if you had access to a ocsilliscope you could scope the signal wire to any sensor and save a lot of trouble shooting.as mentioned just check all the wiring around the engine to make sure that no wires have rubbed through which could also cause a no start or intermittent condition.
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chevy2 said:
I would look at your camshaft sensor located on the right top side of the engine if your sitting in the vehicle.you can follow the wire harness to it along the front rocker cover,it,s a three wire pin connecter.i have personally had issues with a no start and was a faulty cam sensor as it controls fuel timing.if you had access to a ocsilliscope you could scope the signal wire to any sensor and save a lot of trouble shooting.as mentioned just check all the wiring around the engine to make sure that no wires have rubbed through which could also cause a no start or intermittent condition.
Click to expand...

The Cam Sensor Was Bad, So far hasn't had the issue since *Note* There was no Cam Sensor Code, When I pulled out the Cam position Sensor The sensor was cracked and the three wires at the base looked bulged by peeled back the wires and the wires look okay.

If anyone has similar issues I would definitely start with this part.
 
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