I did a compression test today and the reading was between 8 and 9 (low).
am I screwed or what?
Does this mean a rebuild is the next step $$$$$$???
am I screwed or what?
Does this mean a rebuild is the next step $$$$$$???
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By "8 and 9" I hope you mean bar, and not psi.
"Low compression is evidence of poorly sealed combustion chambers. The characteristics of the test results help isolate the cause or causes. Generally, compression pressures that are relatively even but below acceptable specifications indicate worn piston rings and/or cylinder walls. Low but erratic values tend to indicate valve leakage. Dramatic differences, such as acceptable values in some cylinders and very low vaules in one or two cylinders are the sign of a localized failure, probably of a head gasket. Ther are three more tests that can further isolate the problem." (1. Wet Compression Test, 2. Leak-Down Test, 3. Vacuum Gauge Test) - Bentley manual, 4.10, sec. 3.2
Got a Bentley? If not, get one. -
If you pour some oil (not too much) into the cylinders through the spark plug hole, and your compression is higher, then you have piston ring issues. If the compression remains the same, bad valve seats would be my guess. Good luck.
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Well, first off, is it bar, and second off, what engine is it?
8-9 bar = 117-132psi
"See, we're adding a little something to this month's sales contest. As you all know, first prize is a Cadillac Eldorado. Anyone wanna see second prize? Second prize is a set of steak knives. Third prize is you're fired."Comment
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it's a 2.7. And running at idle.Comment
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If it was Psi I don't think it would of been running. How did you do a compression test with it running?85 325e 2.7 ITB'd stroker
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I'd like to know this too.Originally posted by rs4pro3
"See, we're adding a little something to this month's sales contest. As you all know, first prize is a Cadillac Eldorado. Anyone wanna see second prize? Second prize is a set of steak knives. Third prize is you're fired."Comment
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Took plug2 out. Attached gauge to where plug would go. started engine. turned off. And read the gauge.
I didn't do it. I watched my mechanic do it.Comment
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Wow.Originally posted by shields
Just... wow.
Compression tests are done by removing the fuel pump relay, disconnecting the ignition system (removing plug wires/coil wire) and cranking the engine over while the gauge is threaded into the cylinder to be tested.
"See, we're adding a little something to this month's sales contest. As you all know, first prize is a Cadillac Eldorado. Anyone wanna see second prize? Second prize is a set of steak knives. Third prize is you're fired."Comment
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i don't think doing it runnign would give you a very accurate reading. you have a shafty tech on your hands. the piston was mostly on vacuum if it was idling.
if it was 8-9 psi it would definately not have ran. 8-9 bar probably fine if it is 9-10Comment
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Excuse my ignorance.Originally posted by e30Matt
I think this mechanic wants me to sell him my car for really cheap by making me feel like it's shit ans is gonna cost me a fortune to keep. He keeps on telling me he'll take it off my hands for cheap my own good.
Although, my BMW runs great since I've pretty much replaced everything.
Anyways. I figured out the problem
The O2 sensor I had used was a 90 Mustang's and it turns out that it does not work.
Put in a proper BMW sensor and she runs great now.Comment
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find a new mechanic ASAP
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Better yet, screw your mechanic, buy a bentley and invest in some good tools and do all the work on your car yourself. :)1988 325iC - "Betty" - Daily Driver/Project Car.
1993 318i - "The Golden Dream" - Dad's Car.
1995 318ti - "Hellrot" - R.I.P.Comment
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yeah agreed. never go back to that jackass mechanic, and tell all your friends to avoid him.Originally posted by PanamaE30Comment
R.I.P 07/01/09 - 04/23/10 :(
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