2001 Pontiac Grand am,2.4,74k. Sometimes I will get cranking and no compression symptom, in all cylinders. This will happen after a good drive and a few hours later it will crank and free wheel with no compression. Yes the engine is turning.I replaced the oil pump,due to high oil pressure(possible leaving valves open). This symptom will occur once or twice a week. Any other time it runs beautiful.Good maintenance has been kept up and using synthetic oil. Acts as if all the valves are open, then after a few tries with a few minute delay, it will start and run fine.

. During one of these episodes, are you sure there's spark?

. When you turn the ignition switch to ON, do you always hear the fuel pump run?

. Have you changed the fuel filter recently?

Sounds like it's starting in an over rich condition. The cylinders are getting washed down with raw fuel.
This would be injectors dripping fuel after shut down.
Try putting foot to the floor on start up when this happens. Have someone watch out the back for plenty of black smoke when she fires.
When the weather gets cold, this is common with cars that are shuffled in the driveway and then quickly shut off before it had a chance to warm up. Just an example.

Quote:

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Originally Posted by txgreasemonkey

. During one of these episodes, are you sure there's spark? Yes

. When you turn the ignition switch to ON, do you always hear the fuel pump run? Yes

. Have you changed the fuel filter recently?

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No

If I was to disconnect all these items and crank the engine, with the symptom not present I can hear the compression of the engine. With symptom present the engine spins with no compression and sounds like the starter is just spinning, but the engine is turning.

Quote:

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Originally Posted by kitch428

Sounds like it's starting in an over rich condition. The cylinders are getting washed down with raw fuel.
This would be injectors dripping fuel after shut down.
Try putting foot to the floor on start up when this happens. Have someone watch out the back for plenty of black smoke when she fires.
When the weather gets cold, this is common with cars that are shuffled in the driveway and then quickly shut off before it had a chance to warm up. Just an example.

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I did in fact find that the injectors were bleeding down, I failed to mention this. I replaced the injectors for a rough, rich start up. I now have no fuel drop on the injectors. This was done after replacing the oil pump.

Thoughts:

. Have you checked valve lash?

. Could hydraulic lifters be bad?

Quote:

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Originally Posted by txgreasemonkey

Thoughts:

. Have you checked valve lash?

. Could hydraulic lifters be bad?

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I haven't check valve lash because this symptom is only VERY intermittant. Any other time it runs great with no noise and very smooth with good power. I also question the lifters. I have never (30+yrs exp) come across where it can completely shut down compression fully with all cyl's. I am stuck with the problem as to how you can go from a good running drive and sit for a few hours then have an immediate no compression crank. Then after a few tries the symptom goes away. The only thing I can think of is if the lifters immediately pump up at cranking ( I feel like this is a stretch), then they bleed down after a few tries and then I have compression again and everything is happy.

I'm left with the thought that it involves the hydraulic lifters.

Quote:

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Originally Posted by txgreasemonkey

I'm left with the thought that it involves the hydraulic lifters.

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Yes, me too. I have noticed also noticed that in the oiling system there is an oi flow check valve between the lower half of head to block. I don't think that this can cause my symptom either. Thanks for your ideas, if you get more I'm open for them. I will let you guys know if I come up with something also. I have also been told to run a top engine cleaner for any possible valve stem build up that can cause them to stick open. I geuss there is a TSB on this symptom (cold) and this is the remedy for that. I will try it. Could be another stretch. Thanks Again.