Engine cranks however it becomes very hard to start?

MEZZXXFIX

MEMBER
2000 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
180,310 MILES

My truck sits over night and I have no problem starting it. I head out and the engine warms up to operating temperature. I stop for a period of 11/2 hours and attempt to restart it. The engine cranks however it becomes very hard to start. I have tried to step on the gas peddle and everything but it take 2 to 4 time to try to start it Some times it cracks longer then normal to start. Once it start runs rough for a very very short period of time and goes to normal running. Any help you proved will stop me from having mechanic after mechanic trying to figure this one out and burning gas to make it happen to them.

Thank you

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like you might have a faulty crankshaft position sensor.
The crank sensor can fault out with temperature. Typically when the engine is hot/warm the crank sensor will have starting issues.
The reason the vehicle runs rough for a little bit after you start is that is the time when the excess fuel gets burnt. As during the cranking over and not starting the injectors are still spraying fuel to the cylinders and you will have more fuel than its required.

You might find these articles helpful:

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor
https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

I have attached the diagrams for your reference.

Please let me know of any questions.

Thank you.

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