Engine Dies Randomly

[MikeysCars]

My 2004 5.7 hemi will randomly die on de-acceleration. Has always cranked right back on first try, but this morning it took 3 tries to get it started. The engine and majority of the accessories only have 4,000 miles on them and it runs perfect otherwise. About the only thing I haven't changed on it is the fuel pump itself. Any chance that could be causing it? When it dies it's like you turn the key off! Any advice appreciated!!

 

[rzr6-4]

Not a guarantee by any means but fuel pump I would expect it to sputter a bit before shutting off. "Like you turn the key off" sounds electrical.

 

[FabricGATOR]

Is your MIL lit?

4000 miles? How long ago did you baptize her in the fountain of youth?

 

[3pedals]

several years ago when my ‘08 4.7 6spd only had around 250-300k miles, I had a problem where it would cut out ONLY under the following conditions…

90+ degrees ambient temp AND either hit a moderate to large bump/pothole while driving at any speed or trying to reverse uphill, even if only a slight grade

Long story short, an extremely honest local mechanic figured it out while having one of his guys drive it on a lift while he wiggled wires under the hood. Ended up being a broken wire in the very middle of the main engine harness, which when the engine was torqued a certain way, would activate the ASD and try to turn the engine off.

Not saying this is your problem but sounds like the engine torque of deceleration could be causing a loose/cracked/chafed wire to shut things off

 

[MikeysCars]

Is your MIL lit?

4000 miles? How long ago did you baptize her in the fountain of youth?

No, the mil never lit when it would randomly die. I baptized it in July 2022. The other day the mil lit going down the road and it threw a code for the egr so I put a new one on it. I say the other day but it was like 5 weeks ago, it's ran great ever since, even better than it ran before so I hope that was the problem?

 

[Shadow_Death]

several years ago when my ‘08 4.7 6spd only had around 250-300k miles, I had a problem where it would cut out ONLY under the following conditions…

90+ degrees ambient temp AND either hit a moderate to large bump/pothole while driving at any speed or trying to reverse uphill, even if only a slight grade

Long story short, an extremely honest local mechanic figured it out while having one of his guys drive it on a lift while he wiggled wires under the hood. Ended up being a broken wire in the very middle of the main engine harness, which when the engine was torqued a certain way, would activate the ASD and try to turn the engine off.

Not saying this is your problem but sounds like the engine torque of deceleration could be causing a loose/cracked/chafed wire to shut things off

I don't know if the wiring harness is the same on the 4.7L but I have read where people have had the wires run through and ground out on the 5.7L HEMI engines. There is a harness that runs down the front passenger side of the engine. Then it turns back and under the engine. It then runs between the oil pan and the oil filter and back to the crank and knock sensors if I recall. The spot where it turns back is a sharp L shape in the block. I ended up running into this issue on my truck when it rubbed through enough that hitting a dip or a pot hole would cause my truck to die. I wrapped that part of the wire in some old wire insulation and it fixed the issue until I could inspect the wires closer.