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i have a P0302 code. ive checked the sparkplugs/wires injectors etc…then i hooked up a compression tester to cylinder #2 at TDC and hooked up the air compressor to listen for leakes. i heard nothing at the air filter nor at the exhaust pipe but i could hear air going in somewhere. i then took off the oil fill cap and i could hear air through that. does this mean the piston rings are bad?
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q: what is the year/make/model/engine/milage of ye’ vehicle?
q: do you have a COP (coil on plug), CNP (coil near plug), or distributor?
Did you do a compression test? That’ll tell you if your issue is ignition/electrical or if its mechanical. Make sure if you decide to do one that you post both dry and wet results. If your compression test results are off, you could do a leak down test from there to determine if its an issue with intake/exhaust valves or bad rings or head gasket.
+1 on vehicle year make and model.
+1 on ignition system design. If you have coil on plugs, you might have a bad coil.2000 Volvo S40 86K miles. 4cyl turbo. Cyl 3&4 have COP, Cyl 1&2 have wires from those coil packs on 3&4.
Did you do a dry/wet compression test on all four cylinders? If you have a bad set of rings at 86k miles I’d be a little surprised, but then again it is a turbocharged engine… My level of expertise is pretty low, and most of my engine knowledge is theoretical, but bad rings blow low when dry and high when wet… Bad head gasket blows low no matter what. Post some compression test results of all four cylinders, especially since you already have a compression tester! My pea brain can’t help any more without those numbers.
Also, you didn’t mention if you had changed your spark plugs or replaced your coils recently, that may be worth trying if it is due for service.
since its cylinder specific.swap coils 2 and 3.
see if the problem moves. try doing a power balance
test.+1 on a power balance test and swapping the coils.
Does it have a “dead miss” at idle? A dead miss basically means the cylinder is not firing and all and your engine will have a noticable shake and stumble on acceleration.
Your piston rings dont completely seal the cylinder so a bit of blow by into the crankcase (heard through the oil fill cap) doesnt necessarily mean your piston rings are shot. With a misfire diag, ya gotta start with the easiest stuff first
It sounds like your car uses a waste spark style setup, meaning one coil fires 2 cylinders.
since it only has 2 coil packs, how do i disconnect the packs without turning off 2 cylinders?? could i unplug each injector one at a time?
plugs have been replaced as well as the wires but not the coil packs. btw the 2 coil packs are directly connected, on top of cylinders 3 and 4.
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