Hello all,
Edit: 1995 M3 07/94
Recently my car has started intermittently misfiring with the check engine light turning on. It would sometimes turn off as I kept driving or would generally clear up if I turned the car off and back on.
When this first occurred, stomp test read 1274. Last year in spring, I replaced all ignition coils with BavAuto coils so I doubted that the coil was bad but went ahead and put in an autozone coil. The new coil didn’t solve my issue and the code remained 1274.
Next, I changed the plugs and CPS (mainly because it’s one of the few sensors I personally haven’t replaced on the car and the connector was fraying). No change.
Then, I swapped out injectors 3 and 4. Still no change.
This Monday while on my lunch break at work it started misfiring and gave me code 1215 (MAF is less than 3 months old out of Bosch box and I cannot find any vacuum leaks). While I know that this isn’t a wholly accurate test, it did give me some insight into my problem: I checked the ohms of the injectors using a multimeter with the engine running. #1, 2, and 4-6 measured from 0-17 ohms while #3 measured 1.4-1.5 ohms. So I switched injectors 1 and 3 and measured them again. Same results. That tells me my injectors aren’t the issue.
Today, I checked power to all injectors and got 12v with ignition on and 14v with the engine on to all 6. I checked pulse going to injectors and #3 wasn’t getting a pulse. Then I checked the continuity of injector 3 ground wire from injector connector to a few inches before DME connector. Wire was good. So then I swapped DME’s although I had to reuse the chip. Still no change with a different DME except stomp test read 1281. After that I cut that damn injector ground wire and ran a new wire with no change to misfires. Put old DME back in and wiggle tested the power going to the injector and it was a steady 12v. With old DME in stomp test read 1272.
Im at a loss guys. I have to be overlooking something... too frustrated. Please help
Last edited by Campagnaj; 08-15-2018 at 11:39 PM. Reason: Vehicle
Just so you know you cannot measure the resistance of a injector while the engine is running, that is not a test. Your next test is engine compression, you may have a damaged valve. Another thing to check is the wiring in the injector rail, take off the long plastic cover to expose the wiring then with pliers carefully check that the terminals are fully grabbing the injector terminal.
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Be sure two read up on how to do the compression test properly.
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Yep, that’s why I said it wasn’t accurate but it did get me looking at that injector.
Will do a compression test tomorrow, I’ve done the test before but it’s always good to review.
The wiring in the fuel rail looks good. I had that cover off and looked through all the wires. The terminals/connectors all looked good as well. Although the ground wire running through for the coils had a block that was dried out and cracked.
Thank you for your input.
Bump did you ever figure out what the issue was? I’m running into the same issue currently
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