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Discussion Starter · #1 ·
When checking the compression on one of your pistons, what would be a good reading? 93LX - 5.0 - 302. I heard that 110 to 120 is normal but I am hoping someone will clear things up for me.
 

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i would look for at least 130+... but most important, that they all be within 10% of each other.
 

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FYI - I got 160-166 on all 8 on my 79,000 mile stock longblock. Make sure the car is at operating temp before doing the compression test.
 

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Here's a laugher....the great car maker VW, says up to 40% is ok. They are sort of right, it will start and run, but run like baby mustard. I am leaving VW and going back to Toyota, VW is just stupid.
 

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I would agree with the "anything over 100#". But its really the cylinder-to-cylinder comparison you are after. I got a screwy reading on two of my cylinders last time, so I tried a different gauge. The readings were a consistent 22# lower than the old gauge. Both were the same brand, just one was ~15 years newer! Don't be as concerned with overall pressure, look for differences.

PS, I'd recommend a leakdown test if you're really worried. It pinpointed my valve problems! Just my 2 pennies...
 

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Discussion Starter · #9 ·
Thanks to all that replied. maus, thanks, I will try that leakdown test, I just got to get with tmoss. I tested the compression on 2 pistons and they both came in at about 158, I will check the rest this weekend. I found out what the main problem is. I have an injector that went bad and it is not firing. I have been running on 7 cylinders and that stinks. I got some work to do but everything should come together soon.
 
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