05-01-2024, 04:10 PM | #1 |
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F25 x3 strange misfire?
Hello all!
I am currently working on this F25 x3. This vehicle came into our shop after another shop replaced the engine with a used one, and could not diagnose the cyl 3-4 misfire after replacing said engine. The vehicle runs great for the first 15 seconds until the vanos adjusts, then it shuts off fuel to either cylinder 3 and or 4. If I delete the codes while driving it runs great, full boost, no misfiring. When it returns to idle it starts missing again after about 15 seconds. If I disconnect either the valvetronic motor, vanos solenoid, or cam position sensor it goes into reduced power (obviously) but it does not misfire at all. -New plugs -New coils -I’ve flipped the injectors from 1234 to 4321 and re-coded the flow rates -dry compression is 200psi across the board -replaced DME -did a smoke test on the vacuum system -checked fuel trims and compared data to different customers f25 x3. -replaced and relearned valvetronic motor The only codes it throws once it starts missing are 140310 cyl3 misfire 140301 cyl3 cutout 140410 cyl4 misfire 140401 cyl4 cutout Any info into what I could check next would be greatly appreciated. Willing to trade beer for insight. Thanks! Last edited by Pattii; 05-01-2024 at 04:18 PM.. |
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