My 350 shutting off while driving

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Hugomartin

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2 or 3 months ago i got a new fly wheel put on by mechanic, the inner parts were sheard through.. I did not put the bellhousing shroud back on yet ... But anyways the whole truck shut off completley a couple times while driving yesterday , maybe i didnt let it warm up enough or possibly low compression could cause this? I keep reading about vortec heads but im not sure how to really go about the fix to this .last time i looked at my spark plugs i know one of them had buildup on it the rest were fair looking. I have not done a compression test , i dont have the time to fool with it like i want to ... If i bring it to a mechanic what should i tell them to do if my compression is lacking. This truck is a daily driver 87 ' 350 3/4 ton suburban
 

Hugomartin

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It also burns 2 qrts of oil every 400 miles .. The mechanic fixed the rear main seal also when he replaced the flywheel
 

midwest

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I would find a local shop or mechanic that you trust. An engine randomly shutting off twice in a day could be any number of things. Has the oil issue stopped since you had the rear main replaced. 2 quarts every 400 miles is a lot. Also, is there a reason you think it has low compression or is that just one of the guesses you are making?
 

Hugomartin

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I would find a local shop or mechanic that you trust. An engine randomly shutting off twice in a day could be any number of things. Has the oil issue stopped since you had the rear main replaced. 2 quarts every 400 miles is a lot. Also, is there a reason you think it has low compression or is that just one of the guesses you are making?
Yes im just making a guess about the compression, i dont know if that would shut the truck down completely or not?

There is also an old stereo hooked up that doesnt work i need to get in there and remove it perhaps it may be a culprit?

It still burns 2 qrts but doesnt leak
 

pnwnvrdn

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The oil issue, is well, an issue..however not causing a stall out scenario.
Further diagnostics to determine if it's a fuel delivery issue, or ignition.
Shooting from the hip, I wouldn't rule out the ignition control module.
Give your mechanic the entire symptons, and when they occur..he being a professional should be able to replicate the problem, and diagnose/repair the issue.
 

Hugomartin

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The oil issue, is well, an issue..however not causing a stall out scenario.
Further diagnostics to determine if it's a fuel delivery issue, or ignition.
Shooting from the hip, I wouldn't rule out the ignition control module.
Give your mechanic the entire symptons, and when they occur..he being a professional should be able to replicate the problem, and diagnose/repair the issue.
 

Hugomartin

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Any idea wich one is the pump relay
 

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Hugomartin

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V20 3/4 ton 5.7 350 suburban
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I have a peice of coat hanger holding the ignition coil in place missing nut n bolt on one side, the coil is a year old. ... could the coat hanger wire be doing something “odd” to the function of the coil?
 

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Last edited:

Hugomartin

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V20 3/4 ton 5.7 350 suburban
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The oil issue, is well, an issue..however not causing a stall out scenario.
Further diagnostics to determine if it's a fuel delivery issue, or ignition.
Shooting from the hip, I wouldn't rule out the ignition control module.
Give your mechanic the entire symptons, and when they occur..he being a professional should be able to replicate the problem, and diagnose/repair the issue.
do u think i should just buy another coil . Or can i test it?
 

midwest

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Trying not to be rude, so don't take it that way, but based on the questions you are asking it would be easier just to take it to someone.
 

Hugomartin

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Could a slight overfill of motor oil cause a loss of compression? I’m a 1/2 inch past full thanks brothers
 

crazy4offroad

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Ignition coil and ignition control module aren't the same thing. Dad used to say an internal combustion engine only needs fuel and fire to run. Solid advice but the newer vehicles go, more elements are in control of both sides of that basic analogy. I'm all for someone learning more about everything, but if this is a mission-critical vehicle (i.e. a daily driver for work) you may want a mechanic to look at it.
 

Hugomartin

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Trying not to be rude, so don't take it that way, but based on the questions you are asking it would be easier just to take it to someone.
No worries I’m in debt to this page thanks
 

Hugomartin

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V20 3/4 ton 5.7 350 suburban
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Ignition coil and ignition control module aren't the same thing. Dad used to say an internal combustion engine only needs fuel and fire to run. Solid advice but the newer vehicles go, more elements are in control of both sides of that basic analogy. I'm all for someone learning more about everything, but if this is a mission-critical vehicle (i.e. a daily driver for work) you may want a mechanic to look at it.
I have a backup vehicle but I am interested in testing what’s what
 

crazy4offroad

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First thing I'd say is add an auto ranging multi meter and a year/ model specific repair manual to your tool collection. It'll have full details to identify and test components, like your fuel pump relay, ignition coil, ignition module, etc. To suddenly shut off like that implies ignition/ electrical so I think you're on the right track. Wish I could be more help but I'm at work, just checking now and then. Also I'm mostly a carb guy, not really familiar with factory fuel injection systems on these trucks.
 

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