Okay I know what to do but I am not sure which fuse or relay to pull. Also what are the average compression numbers that a high mileage 900 Turbo should be able to do? Thanks in advance.
Nothing led to me doing this test. I just wanted to see what it was considering it had pretty high mileage. I might do the oil test but I don't really want to have to replace the rings or even the headgasket to fix anything. I just wanted to make sure the car was running okay on all 4 cylinders and to make sure I didn't have like a burnt valve or anything. They all seem to be close enough to eachother where I'm not to worried about it. Besides I only paid $500 for the car to begin with. I just lucky it's in this good of shape.DC_SAAB said:based on your readings....I'd say #4 is suspect, and you should add oil to all four and retake the test... to see if it changes. Good if it increases, but bad if it doesn't. The low readings indicate something more to look at.
If this was a V8 I'd start thinking about replacing the head gasket considering how close those readings are in the adjacent cylinders. Replacing head gasket on a high mileage car is a whole lot cheaper than replacing a warped head.
I blew a gasket internally as opposed to externally, so was hard to detect...other than the red idiot light came on (hmm no wonder..lol) ...so was hard to see. Supposedly most SAABs blow head-gaskets by design internally, but there are exceptions to the rule.
Have you noted anything leading you to suspect something might be wrong to do this type of test? i.e..., loosing coolant, milkey brown oil...(definately time to investigate the problem then), or something like that indicating it might be time to consider, or just saw the high mileage and thought it was time?