Scouttster

2011 hhr with 108k

1) 220
2) 225
3) 220
4) 210
Numbers are high?
Tested, WOT on a 198° F. vvt engine..

firemangeorge

Most likely the wrong testing procedure or faulty test gauge.

Maybe an explanation of why you're doing a comp test. Would help us to better understand what you're looking for.

RJ_RS_SS_350

Those numbers do seem high. It's recommended to do the test cold or slightly warm, but only because removing the spark plugs on a hot, aluminum engine is risky(thread damage, stuck plug). Did you pull the fuel pump fuse and run it out of fuel prior to testing? That may have a slight effect, but I wouldn't expect much change in your results.

Different test equipment can give different results also. If you have access to a different tester, you could retest. I would expect numbers in the 140 - 180 range. High compression like you are seeing may be the result of carbon buildup on the piston.

My search here showed 1 other with similar results, but the thread was a dead end.
https://www.chevyhhr.net/forums/prob...ell-fix-40393/

donbrew

Just guessing; if it is "hot" vs "warm" perhaps the VVT has not adjusted itself to cold, thus giving very short durations?

Scouttster

Negative on the pulling of fuses.
Tester is hardly used, but old.. It could be broken.......
High numbers, albeit all in the 20% range of each other.. Im in S Florida.. Hot hot hot!

Oldblue

A thread in tester? Or push to plug hole and hold ?
I'd pull the fuel pump fuse and redo the test.

Scouttster

Yes, its your regular plain old HF thread in or screw type tester..

Oldblue

Try a new tester , the old one could be toast