Misfiring and brakes fade. Please help!
#1
Thread Starter
New Members
Joined: Dec 2022
Posts: 26
Likes: 1
From: Pa
My Ride: ‘08 535xi
Model Year: 2008
Engine: N54
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.
#2
Super Moderator
Joined: Jul 2011
Posts: 3,708
Likes: 328
From: Augusta, GA
My Ride: 05 530i M54
Model Year: 05 530i
Engine: 3.0 M54
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?
#3
Thread Starter
New Members
Joined: Dec 2022
Posts: 26
Likes: 1
From: Pa
My Ride: ‘08 535xi
Model Year: 2008
Engine: N54
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.
#7
Super Moderator
Joined: Jul 2011
Posts: 3,708
Likes: 328
From: Augusta, GA
My Ride: 05 530i M54
Model Year: 05 530i
Engine: 3.0 M54
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.
The following users liked this post:
bimmerdad74 (06-05-2023)
#8
Thread Starter
New Members
Joined: Dec 2022
Posts: 26
Likes: 1
From: Pa
My Ride: ‘08 535xi
Model Year: 2008
Engine: N54
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.
#10
Thread Starter
New Members
Joined: Dec 2022
Posts: 26
Likes: 1
From: Pa
My Ride: ‘08 535xi
Model Year: 2008
Engine: N54
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?