Mechanics

WHAT ELSE COULD CAUSE MY TO LOOSE SPARK WHEN ENGINE IS WARM?

1994 Dodge Van • 164,000 miles

1994 dodge ram van 150 runs fine untill engine warms up but then it won't start. It's loosing spark it turns over but won't start problem is worse when its warm outside I've already replaced coil, sparkplugs, plug wires, distibuter cap, distributer pick ups, crank sensor, and it still does it any ideas?
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Tedow
August 14, 2012.



There's three circuits that can be involved and the parts you put in are in two of them. First figure out if you're losing fuel pressure along with spark. The easiest way to do that is by measuring the voltage coming off the automatic shutdown (ASD) relay. You can do that at the 12 volt feed to the ignition coil, any injector, or either small wire on the back of the alternator. You should see 12 volts there for one second after turning on the ignition switch, then it will go back to 0 volts. What's important is whether that voltage comes back during cranking.

Caradiodoc
Aug 14, 2012.