Dear Jbody enthusiasts,

I'm trying to diagnose an extended crank/hot-start problem on my 99 Cavalier, 2200 3-spd auto.

For giggles, I attached a vacuum gauge between the FPR and the throttle body. I was not pleased with the results - the needle fluctuates rapidly between 16mm/hg and 19mm/hg, and it steadies when you rev the engine.

In many places, I've read that this is usually a sign of worn valve guides. However, my engine isn't consuming any oil.

Do these engines have a history of having timing chain problems?

~Anthony

Not valve guides, valve springs are what your problem most likely is


- 2004 Cavalier - 124k, owned since new

If the valve springs were weak, wouldn't the fluctuation get worse as the engine RPM's increase?

Also, I'm not having any misfires at high RPM's, either...

illtmprdman wrote:If the valve springs were weak, wouldn't the fluctuation get worse as the engine RPM's increase?

Also, I'm not having any misfires at high RPM's, either...

No, because you have less vacuum as RPMs increase, you have about 28hg of vacuum at idle, with wide open throttle it drops to like 8 or 9hg.

Valve springs cause a flucation at idle with readings between 14-19hg.

Worn valve springs dont always cause a misfire.


- 2004 Cavalier - 124k, owned since new

Try hooking up straight to the tb.

blue02zee24 wrote:Try hooking up straight to the tb.

It shouldn't matter.


I'd do a compression check and go from there.