Misfiring and brakes fade. Please help!
06-06-2023, 04:47 PM
#11
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My Ride: 05 530i M54
Model Year: 05 530i
Engine: 3.0 M54
Test it by starting the car for about 30 secs and turn it off for 30 secs then pump the brakes. If the brake pedal starts to get hard after a couple pumps then it's good. If it doesn't then you'd have to test it with the vacuum hose clamped closer to the booster to bypass the check valve. If it gets hard the the check valve is bad or hose (it's an assembly anyway) if it doesn't get hard then the booster is bad.
You're say you're getting that high on the rail then it goes down to 5000k which should be LPFP pressure. I'm confused by that if that's what you're stating
You're say you're getting that high on the rail then it goes down to 5000k which should be LPFP pressure. I'm confused by that if that's what you're stating
06-06-2023, 05:03 PM
#12
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Test it by starting the car for about 30 secs and turn it off for 30 secs then pump the brakes. If the brake pedal starts to get hard after a couple pumps then it's good. If it doesn't then you'd have to test it with the vacuum hose clamped closer to the booster to bypass the check valve. If it gets hard the the check valve is bad or hose (it's an assembly anyway) if it doesn't get hard then the booster is bad.
You're say you're getting that high on the rail then it goes down to 5000k which should be LPFP pressure. I'm confused by that if that's what you're stating
You're say you're getting that high on the rail then it goes down to 5000k which should be LPFP pressure. I'm confused by that if that's what you're stating
Last edited by donpb; 06-14-2023 at 09:12 PM. Reason: Fixed end quote syntax
06-06-2023, 05:26 PM
#13
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My Ride: 05 530i M54
Model Year: 05 530i
Engine: 3.0 M54
Ok so it got up to 2000+ psi on cold start I don't see it as a HPFP issue. I didn't want to bring this up because I hoped it wasn't the issue. Do you have the MSD80 DME? Still wanting to see what the booster test reveals
06-06-2023, 05:34 PM
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06-06-2023, 05:38 PM
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My Ride: 05 530i M54
Model Year: 05 530i
Engine: 3.0 M54
So the MSD80 has MOSFET issues and need to be replaced. They directly control each of the injectors. 1 for each cylinder. Most upgrade to the MSD81.
06-06-2023, 05:46 PM
#16
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I knew about the mosfets and just read on eBay that misfires are possibly a mosfet issue. I can repair electronics. Is there another benefit of upgrading to 81?
06-06-2023, 06:03 PM
#17
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Not really. Just prevention. If you can repair I would definitely go that route to save some money if yours is having that issue
06-24-2023, 09:57 AM
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Is it repairable. If you don't have the program to clone the DME you'll have to send it in to see if it can either be repaired or cloned to a new one. DMEs are not plug and play.