Looking for some advice on an issue, more a second opinion or some possible tests to validate.

Basic information: Van has had a skip on acceleration for some time, changed all ignition components. About 6 months after the van died on the road and would just cranck, checked for spark and fuel. Found week spark at the plugs, changed pick-up in the distributor and crank sensor in the bell housing (they have never been replace up to that point). Still week spark at the plugs. Engine attempts to start, diesels when key is release on crank. I suspect something with the ASD circuits or the PCM, attempted to ask the dealer if there was a flow chart that they could print off to check/test the ASD circuits and PCM. They were less than accomodating. If anyone could assist i would be most gratefull. Thanks

 

Including the ignition coil? If not I would change that, but if you did I would next suspect the timing chain of having jumped a tooth or two due to the dieseling.

 

Alloro,

Thanks for the input. I did check the timing, but did not replace the coil. The spark from the coil to the top of the cap is strong, but at the plug it seems week, what makes me think that it is something with the PCM or another sensor.

 

That would indicate a loss of power at the distributor; as if the rotor is not lined up with the tower when the spark is fired off, or the spark plug wires are no good, especially the one from the coil.

Since the PCM adjusts the ignition timing, the timing chain could've jumped a tooth making the valve timing be off, while the PCM in turn corrects the ignition timing. This process can give you a false positive and make you think the valve timing is okay, when it might not be.

Line up the timing marks and then pop off the distributor cap. Where is the rotor pointing when looking from the back of the engine? It should be in the 1:00-2:00 range.