Helllo could someone tell me what good to bad compression numbers would be on my 02 f4i ,also should motor be hot or cold ,best way to get results .any help would be great thank you

 

The specs call for 178 psi and the engine should be at operating temperature. I would think that anything above the 150 psi mark and you're probably just fine. Primary thing to look for would be consistency across all cylinders. Variations of 10 or 15 psi is nothing to worry about. Having 1 cylinder significantly different than the others would probably indicate a problem. Check it twice to make sure it wasn't something you did during the check that caused it.

 

all cylinders should be within 10% of each other. If there's one cylinder that's reading vastly different than the others, do a leak down test. This will help you pin point the problem area. A leak down test is much more revealing than a comprehension test.

 

thank you both for your replies, ,this is good!!!!!!!!

 

make sure your battery is fully charged for every cylinder or you'll get lower numbers the further along you go as your battery dies.