Trying to help a friend, 39 Plymouth with a 5.7 Hemi that came out of a 2004 Magnum. Problem started out as intermittent no start last year( just like a dead battery, nothing), leave it for an hour and fired right up and ran fine, replaced ECM and had VATs disabled thinking this might be the problem. Now starts fine when cold, when hot exactly the same as before, need to leave it at least an hour with the hood open to cool, starts up again and runs fine. Now in the last few days, after driving for 5-10 minutes, looses power, won't go over 30 mph, if you shut it off, won't start until it cools right down. Now when I say it won't start, it's dead, won't turn over, fuel pump doesn't turn on, nothing.He says the radio and headlights still have power when this happens. He's hooked up his OB2 reader and no codes.
Dont know about the no power over 30 thing, but the no starting sounds like the older Chevys with the heated up solenoid thing. Have you tried jumping the starter when its hot?
If the fuel pump is not turning on, then the problem has nothing to do with the starter.
The only way you're going to figure this issue out is by getting the car to Chrysler and have them connect their scanner to it. Hopefully when you get the no-start condition again, they will be able to see why. I would also suspect the VATS system, but you say it has been disconnected so it shouldn't really come into play.
Next time this happens, check to see if the ECM is getting power.
-- Edited by hemi43 on Friday 26th of July 2013 08:58:35 AM
Dont know about the no power over 30 thing, but the no starting sounds like the older Chevys with the heated up solenoid thing. Have you tried jumping the starter when its hot?
ive seen a problem in some newer stuff involving aftermarket starters that wont crank due to voltage issues when hot. friend of mine has a ford truck that wouldn't start most of the time, turns out new starter wasn't getting enough voltage through hot wire so they bought genuine ford starter and no problem after that. losing power though while driving sounds like a funky ground issue which also could explain no starting. is ground wire from the battery connected to an aluminum bracket? aluminum can be a poor conductor at times. sounds like grounding to me
Only way to find it is to carry your meter and start tracing the power when it quits. Almost seems like a heat sink breaker to reset itself after it cools. Start at the basics correct voltage proper grounds .
It seems like multiple issues to me. I'll bet that there is some key information not getting to the ECM which is causing it to go into 'limp mode'. Now you just have to figure out why no codes are showing up. The loss of power and shutting down are necessary evils built-in to protect the engine from excessive damage - be thankful they thought of that for you. Bad grounds is always a great place to start because it only costs time. Next, go after the sensors and knock them down one at a time. A shop manual will have the spec values and ranges for each or you might be able to download from the www. Good luck!!!
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