Compression test results?

[voodooRunner]

I tried to do it while the engine was warm, but it took me forever to get my plugs out, so I doubt it was anywhere near operating temperatures.

I ran the test 2-3 times on each cylinder. In almost every case, the value dropped after the initial reading before stabilizing. (normal?)

On the 8th cylinder the value continued to drop with each subsequent reading and the tester had gasoline in it when I removed it.

Here are all my 1st & 2nd readings:

#1 175 170
#2 168 165
#3 161 161
#4 159 152
#5 170 169
#6 165 165
#7 171 166
#8 210 200 190 180 175

Did I flood with all the cranking? And is that why #8 was so skewed perhaps? Any interpretations of the rest of results? My engine has been smoking.

Thanks,
VR

 

[TurboDoctor]

Not sure how you got fuel inside your tester, the Schrader valve should have not let fuel into the tester. The results look pretty consistent. The number 4 cylinder looks a little off. I would redo your test again. I have never been a real believer in the fact that there can be a real accurate compression test. Too many factors come into play. They are however helpful in isolating a problem and getting you started on where to look. You said your engine is smoking, Have you had any head work done? How many miles are on the engine? I would start by checking the valve seals and doing a leak down test on the cylinder. Leak down tests in my opinion are more accurate, I know some people disagree with that. Also what color smoke are you getting?? Give us some more details so we can help you out some more. Good luck

 

[voodooRunner]

I'm not sure either, but the hose definitely had a fair amount of fuel in it when removed. There was also a mist (not sure what) spurting from the left side of the engine, difficult to pinpoint where (maybe the exhaust manifold or head gasket?) each time I cranked.

The smoke is white and comes from the right side. It starts almost immediately now. I just got the car, so I'm not sure about head work. It was supposedly rebuilt about 15 years ago. Engine says about 87k but I have no idea if that's accurate.

Engine smoke started after the car had been repeatedly overheating during a lengthy drive.

I can retest the compression tomorrow and i will have to wait for the proper equipment to do a leak-down test. But if anybody can comment on what might be going on based on the current test results and the other symptoms that could be a helpful start.

Should I do a wet compression test next time?

 

[TurboDoctor]

Well the white smoke is indicative of burning oil in most cases. Try pulling the plugs on that side and cleaning them really well. Reinstall them and run the engine. Pull the plugs out and see if you got one that is has a lot of residue on it. But you also said it was overheating. Make sure you have antifreeze in the radiator and when the car is running go the tail pipe and try to smell the exhaust. You will be able to smell if it has a burnt oil smell or if it has that sweet smell of anti freeze. Have you been having to add oil or coolant to the engine??

 

[69Rcode_Mach1]

From my experience if it's burning white then you are burning antifreeze indicating a bad head gasket. Oil burns blue.

 

[voodooRunner]

Yes, I believe white smoke is supposed to indicate burning coolant. Either way, the fact that it's coming out from the engine instead of through the exhaust should tell me that I have a leak somewhere on the engine, right?


I attempted to do a wet compression test today. I really wanted to test #4 and #8 again since they deviated most from the other readings. #4 was about the same, low 150s. #8 continued where I left off, moving lower and lower: 160, 150, 141...

Bottom line is that I realized gas was squirting out of the #4 and $8 spark plug holes when I was cranking. IS THIS NORMAL?

 

[TurboDoctor]

Pressurize the cooling system and check for a leak if you are suspect of a coolant leak. Sounds like you need to a leak down test and check your valves and head the condition of your head gasket.

 

[voodooRunner]

So is it normal for gas to spray out of the 4 and 8 spark plug holes when running a compression test at WOT? The front 6 holes are just blowing air.
Thanks.