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Misfiring and brakes fade. Please help!

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Old 06-04-2023 | 07:56 PM
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Default Misfiring and brakes fade. Please help!

Hey guys. I’m in need of help. This car is killing me. First, the car used to run bad on cold start then it was fine after 2 minutes. Then the brake pedal intermittently hardened up. Now continuously has light misfiring in all cylinders. I did smoke test it and fixed the leaks. Adaptive reset. In the past year I put in new plugs and coils, walnut blast, all oil leaks sealed and vanos. Recently replaced injectors and coded, fuel pump and filter, 1/1 O2. Ordered downstream o2’s. Adaptives are -20+, hopefully foxwell pics will post. Codes are misfires in all cylinders. But I’m at a loss. Any help would be greatly appreciated!
















Last edited by bimmerdad74; 06-04-2023 at 08:28 PM.
Old 06-04-2023 | 08:12 PM
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What are your HPFP numbers? Are you sure you fixed all the vacuum leaks. What current codes do you currently have? Are you using OEM parts or cheap aftermarket parts?
Old 06-04-2023 | 08:24 PM
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I used mostly Bosch items. I believe rail pressure is hpfp pressure? I didn’t see any more smoke but I will test again. Misfire codes for all cylinders.
Old 06-04-2023 | 08:27 PM
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Turbos we’re also replaced 3-4 years ago as well as map and boost psi sensors with oem parts.
Old 06-04-2023 | 09:30 PM
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Your pressures are definitely too low. What codes are you getting? Are you tuned?
Old 06-05-2023 | 08:53 AM
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Misfire codes for all cylinders. No tune. Completely stock. Which side are you stating is low? Low or high side?
Old 06-05-2023 | 08:57 AM
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I looked at the high side. You're around 750 psi and that's way too low. You should be between 1200-1500 psi. Your LPFP is right on target at 72 psi which is what the DME sets it at

Last edited by seanjordan20; 06-05-2023 at 09:47 AM.
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Old 06-05-2023 | 09:56 AM
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Originally Posted by seanjordan20
I looked at the high side. You're around 750 psi and that's way too low. You should be between 1200-1500 psi. Your LPFP is right on target at 72 psi which is what the DME sets it at
ok. Here’s the next question. The computer is removing fuel as shown by the adaptives. Why isn’t it adding fuel? Unless, this foxwell is vague and it’s actually showing the short term instead of long term. I have an extra hpfp I can try. Thank you for the spec. I thought I looked it up but I’ve been so frustrated I can’t remember.
Old 06-05-2023 | 11:15 AM
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Forget last question. Sometimes when I see the question I can answer it myself. 🤦🏽‍♂️
Old 06-06-2023 | 04:29 PM
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No luck with the hpfp. Starts at 179k hpf to idle at 5k. Hard throttle back up to 179k +. Is it possible that a leaky brake booster may cause this?



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