Hey whats up,
My 98z runs alittle rough at idle.No vac leaks,new ignition components etc.Car thows a cel for a misfire when the car idles on a cold start.If i drive it right after a cold start,it wont throw a code.Also has some blow by.Compression is good across all 4 cylinders.Havent done a leak down test so it could be worn rings.Now heres my question.If the timing chain jumped a tooth,would it cause blow by?The reason im thinking it might be the cam timing is because when i scan it with hpt,the timing is all over the place at idle.When i give it alittle gas it smooths out.you think this could be the cause?


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

i assume HPT is reading spark timing not mechanical timing.

Blow by has nothing to do with cams. It would mean that you're either FI or your rings are shot.

And you're reading spark timing in hpt not cam timing.


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probably has bad plugs/or the plastic plug boots i know my Z had a misfire code. so i changed the plugs ,plug boots and it was fine

Yea I know i was reading spark timing in hpt.but if the cam timing jumped,wouldn't it mess with the spark timing since the timing is out of sync?I realized after I posted that it wouldnt cause blowby.I don't know why I wrote it.The reason I think the timing jumped a tooth is because it's a little lopey at idle.when it gets a little warmer out I'm gonna take off the timing chain cover and check it out.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust