Tried a used compression tester from a pawn shop and it read 20 PSI low compared to my Snap-On one

I pulled a head on a 5.3 Vortec based on that cheap gauge only to find the rings were fine, so has anyone else had a tool give a bad reading that cost them real time and money?

3 comments

3 Comments

leelewis29d ago

That bit about the cheap gauge reading 20 PSI low hit close to home. I had a similar headache with a timing light I grabbed at a flea market once. It was missing a ground wire or something inside, so it would fire at the right time at idle but jump all over the place when you revved it. I chased a phantom misfire on my old S10 for three weekends, replaced the distributor cap, plugs, and wires, only to find out the light was the liar. Ended up borrowing a friend's old school Sun machine and it ran perfect with no change. Did you end up tossing that pawn shop tester in the trash or keep it around for a laugh?

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the_morgan26d agoTop Commenter

Kept it as a trophy actually. Sits on my toolbox as a reminder that I'm the kind of person who'll replace half an engine before realizing the tool was the problem.

claire_walker29d ago

That flea market timing light thing really proves cheap tools are a gamble you don't win at.