Sup yall, I just did a compression test and I was shocked to see the results. They were as follows; L-R 150-160-145-170. Here is some background on the car. Its a 2003, 117k, doesnt smoke, doesnt burn excessive oil, and it doesnt run hot. It runs strong and drives just like it did bone stock. I drove my car for years before I started adding parts. In fact I put about 50k on it making less than 350whp. I barely drive it and when I do I very seldomly go WOT. I dropped a cap full of oil in the lowest cylinder and the compression DIDNT rise. Its full bolt-on now with an upgraded turbo and it runs even stronger. The test was performed twice just to make sure it wasnt user error. Im stuck on this one yall.

I'm thinking headgasket but the car doesnt over heat at all?!?

Any suggestions?

 

shocking search

 

Looks like a normal engine with some miles on it to me. Normal compression is 163 and the service limit is 138.

 

How many times did you crank the motor over per cyl? Was it hot or cold? Did you remove all the plugs to do the test?

 

The first test it was cranked for about 8 seconds. The second test was held until the needle stopped. The motor was warm and all of the spark plugs were removed.

 

After reading it appears that I was supposed to disconnect the crankshaft position sensor. I just realized that I disconnected the cam angle sensor instead. Not sure how I got the two confused. Do you all suppose that matters or makes a difference?

 

Bump for more info

 

You can either disconnect the cam angle sensor, crank position sensor or just pull the fuel pump relay. All that does is make sure the car dosent start while you're performing the test. Since the numbers didnt change with the oil i would say the problem might be with your valves sealing. those numbers arent terrible but its hard to know the full extent of the problem without doing a leakdown test. After that test you should find out if its your intake valves, exhaust valves or the rings. good luck!

 

Test compression on a new Evo 8 engine and all the cylinders will read around 160. Drive it 100,000 miles and will it still test the same? No, the engine will show some wear. The reason for a compression test is to determine if wear is sufficient to justify repair. In your case the answer is no, drive it some more.

 

Could be the tune. LOL.