Question I've done a complete tune up on my truck plugs wires button cap pick up coil and coil. Truck ran great but when I parked it for the day and came back out next morning and it wouldn't start. I checked the firing and all was good. I pulled a plug and it was soaked in gas. I changed plugs again. Started right up and ran good throughout the day with shut offs and restarts. I parked it for the day again and next morning the same exact thing happened again. Overnight it gas soaked all plugs again. What makes it foul the plugs overnight???
Answer Hi Ashley,
All I can imagine is that the fuel pump may be continuing to run after you shut off the engine and over time the on-going pressure on the fuel rail is causing the injectors to leak overnight. I don't see how all the injectors could be stuck open and in any case they would be damaged if they were activated continuously for a minute or so by their driver wires being grounded. The power for the injectors should be removed in any case when the autoshutdown relay opens when the engine is shut down. So listen for the fuel pump to still be running when you shut down the engine. It is controlled by the pcm rather than by the ASD relay so it is possible that it hasn't been cut off.
I wonder otherwise if there is some sort of a temporary failure of the injector drivers/spark at initial start up but I can't believe that would soak the plugs.
Let me know what you find.
Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.
I answer questions seven days a week and respond to you in about 30 minutes. "Maxed Out" means I am answering another question or briefly unavailable so try again later.
I have do-it-yourself experience (50+ years) and a library of 100 1982-2012 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.
I was voted "Top expert" from 2010-2015 here at AllExperts, and have answered 20,000+ questions.
Five decades as a 'do-it-yourselfer' on domestic and imported cars
Organizations Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)
Education/Credentials Degrees in Physics/bruised knuckles.
Awards and Honors "Top expert" of 2010, 2011, 2012, 2013, 2014, and 2015 here at Allexperts.
Quickest "average response time" at Allexperts (currently no. 1).