Just did a compression test using the Autozone rental program and the results were too low!

all 4 cylinders were between 90-95ish psi

Car runs fine outside of some weird noise on deceleration (throwout bearing?) and pulls real fast(quicker than my friends '13 WRX)


any ideas?

 

Hmm...90-95 psi sounds fine...pretty common for many...what did you expect?

Maybe a 9000 rpm overrev? Maybe something is getting ready to go...and that's the deceleration noise?

A throwout bearing will rattle when the clutch is NOT engaged.....
Like idleing in neutral....

 

Gollum the 1st - an R53 - pumped 150. 145. 145. 145 at 53k miles.

That's what I would expect.

Perhaps the rental equipment, or the method of test were not correct?

Cheers,

Charlie

 

Yes that sounds low. Consistent but low. Was the equipment good? Motor on.

 

Since the numbers are consistent across all 4 cylindars with a rental tool....
My gut is it might be miss calibrated...
If a car runs good, makes good power, and the readings are even...you are good.
Numbers come up in posts literally all over, thats WHY I suggested it is "normal".

 

I doubt the overrev did anything as it drives and sounds exactly the same as before.

I screwed the compression tester hand tight then proceeded to do 10 seconds of cranking. i even tried cranking it for 15 seconds but the result was the same, no more than 95ish PSI

My R53 that i had last year, albeit with difference equipment, got around 160 PSI all around. Hopefully it's just the autozone tester?

and YES, the car drives fun and idles perfectly and is REALLY QUICK


I was just doing the compression test to see if the car is worth spending more money on(mods).