SOLVED Losing fuel pressure and my sanity :(

[Dandy.93]

Hey there lads. Never thought I would have to post on forums for help but here I am. I have a 2008 335i (N54).

So recently my car has been feeling horrible and having symptoms of HPFP failure :
1. Rough cold start
2. Feels like misfires when under mild acceleration.
3. If I accelerate for more than a couple of seconds the engine shakes and violently jerks the car, cutting the turbos out and shutting off the HPFP. Rail pressure drops and matches the low-pressure fuel pump (85 psi). This causes the car to blast the radiator fan to full power and go into limp mode. I can temporarily solve this by shutting the car off and on again.

Oh and another thing.
4. Odd high pitched siren/whistle sound when under acceleration and metal clank noise? But no wastegate rattle. Might be a separate issue?

Codes :
29f1 - Fuel pressure plausibility
29cf- Misfire (probably caused by the drop in fuel pressure)

Since I know it's pretty common for our HPFP's to fail, I ended up buying one off FCP euro for $780 and installed it.
BUT unfortunately no luck. The car still violently jerks and shuts off the HPFP and I don't know why. I'm losing my damn mind with the car and I've only had it for a year.

I managed to make a quick log after installing the new pump showing the fuel pressure dropping and skyrocketing my afr:

datazap.me | angelz0418 | Crap

datazap.me

And this is what INPA showed in error memory:

It appears that the P-Code assigned with the 29f1 code is P3284. Definition: Fuel pressure control Bank 1 calculation of adaptive fuel volume implausible.

I'm fairly new to the car scene so any help would be greatly appreciated!.

 

[JohnDaviz]

So besides the rail pressure.

Looking t your posted log makes me raise my eyebrows.

As soon as your log starts you get this:

Your Lambda AFR Bank 1 is rich af although STFT1 is pulling max fuel (-34%).
There is something going on on your Bank 1 which may correlate with defective injectors. There may be one or more stuck open.

OR your tune is fu**ed up badly.

 

[RuskiRacer]

If you have a catch can on the car you should be able to tell if the injectors are leaky. It should have some fuel in there.

 

[TheFixer]

I just started getting a slight smell of fuel on cold starts. I should probably check the filter. Where is the fuel filter located? Is it under the car after the fuel regulator? Thanks.

Under the rear seat, drivers side..... on a 535i. Think it is the same for you.

 

[JuniorB]

Since you done eveything from the pump back, shtart looking from the pump foward. Check the adapter off the vac pump, the gear itself, sprocket, and chain. If at high revs, there is slippage. That pump is all mechanical to run, if you’ve checked all else, start looking at what drives it.

 

[NoQuarter]

Make sure the large battery cable that connects to the alternator is in the factory mounting tabs and routed as intended.

If it is left unattached and lays freely, it can get too close to the hpfp solinoid leads and affect the pwm signal. If the hpfp does not behave as expected, the DME will shut it down and turn the fan to max.

Similarly, check the HPFP solinoid connector for any corrosion or suspect wire issues.

Jim

 

[doublespaces]

Make sure the large battery cable that connects to the alternator is in the factory mounting tabs and routed as intended.

If it is left unattached and lays freely, it can get too close to the hpfp solinoid leads and affect the pwm signal. If the hpfp does not behave as expected, the DME will shut it down and turn the fan to max.

Similarly, check the HPFP solinoid connector for any corrosion or suspect wire issues.

Jim

Oh really? Do you have more information on how you discovered that? I'm starting to think my cable isn't in the original position, have to go check now.

 

[NoQuarter]

Oh really? Do you have more information on how you discovered that? I'm starting to think my cable isn't in the original position, have to go check now.

First hand experience during my HPFP experiments with the piston style pumps and the stock rotary style.

When I put it back to stock I was missing the factory cable holders so left the cable whereever it rested. I couldn't get the stock HPFP working correctly so assumed I ruined the solenoid at some point. Turns out the solenoid was OK afterall and moving the battery cable away from the hpfp seems to have been the culprit.

 

[Dandy.93]

lmao, still no fix. BMW of Dallas has been useless. So far has had all new injectors, HPFP, LPFS, HPFS, and Vanos. I guess i gotta just throw money at it until it gets fixed. Thinking it might be ekpm or fuel regulator or maybe ecu. The whining/ electronic buzzing noise is still there and the jerking/stuttering is worse than ever. Injectors fixed fuel smell but the car still jerks so hard it feels like the traction control cut power. The car seems to run better in fuel mode 15 which is open-loop I believe.

 

[SLOWESTN54]

lmao, still no fix. BMW of Dallas has been useless. So far has had all new injectors, HPFP, LPFS, HPFS, and Vanos. I guess i gotta just throw money at it until it gets fixed. Thinking it might be ekpm or fuel regulator or maybe ecu. The whining/ electronic buzzing noise is still there and the jerking/stuttering is worse than ever. Injectors fixed fuel smell but the car still jerks so hard it feels like the traction control cut power. The car seems to run better in fuel mode 15 which is open-loop I believe.

Just a question sorry if i missed this somewhere. But is your car tuned, if so is it a DME flash or a JB4?

 

[Dandy.93]

Just a question sorry if i missed this somewhere. But is your car tuned, if so is it a DME flash or a JB4?

Hello, my bad forgot to mention the car is completely stock. No tune or anything.

 

[iminhell1]

Look at timing chain and components IMO.

 

[Dandy.93]

The problem was found after 1 year and four months. In case anyone else has to go through this rabbit hole according to BMW of Arlington the issue was damage on the cylinder head. Caused by an incorrect injector bracket bolt. It was slightly longer than the correct one and it "punctured the crankcase". Surprisingly after 120k miles, my compression was 190-198 psi on all cylinders. Pretty good but oh well.

 

[fmorelli]

The problem was found after 1 year and four months. In case anyone else has to go through this rabbit hole according to BMW of Arlington the issue was a hairline crack on the cylinder head. Surprisingly after 120k miles, my compression was 190-198 psi on all cylinders. Pretty good but oh well.

The car is fixed and no longer has the issue?

 

[Dandy.93]

The car is fixed and no longer has the issue?

Well no sadly. The dealer charged too much for a new cylinder head. But confirmed that was the issue. I already spent 4k+ in just the diagnostic process alone + some other issues BMW wanted fixing first (including a $1400 walnut blast, they wouldn't continue the diagnostic without it). I'm considering just replacing the whole engine at some point but not now.

 

[fmorelli]

Well no sadly. The dealer charged too much for a new cylinder head. But confirmed that was the issue. I already spent 4k+ in just the diagnostic process alone + some other issues BMW wanted fixing first (including a $1400 walnut blast, they wouldn't continue the diagnostic without it). I'm considering just replacing the whole engine at some point but not now.

So to be completely objective, we don't know that this is the issue. This is what they claim the issue is. Proof is in the solution. BTW where is the crack specifically? (wondering where all that pressure is going)

 

[SLOWESTN54]

The problem was found after 1 year and four months. In case anyone else has to go through this rabbit hole according to BMW of Arlington the issue was a hairline crack on the cylinder head. Surprisingly after 120k miles, my compression was 190-198 psi on all cylinders. Pretty good but oh well.

Did they ever explain the reason they think a crack in the cylinder head will cause fuel pressure drop?

 

[colo_evo]

So to be completely objective, we don't know that this is the issue. This is what they claim the issue is. Proof is in the solution. BTW where is the crack specifically? (wondering where all that pressure is going)

Well put.

Damn, was hoping you'd find the solution. Time to sell the car and move on.

 

[mikeseli]

Well no sadly. The dealer charged too much for a new cylinder head. But confirmed that was the issue. I already spent 4k+ in just the diagnostic process alone + some other issues BMW wanted fixing first (including a $1400 walnut blast, they wouldn't continue the diagnostic without it). I'm considering just replacing the whole engine at some point but not now.

I have an extra N54 cylinder head that has no damage and everything is in good working order. I can sell it for $300 shipped.

 

[Dandy.93]

So to be completely objective, we don't know that this is the issue. This is what they claim the issue is. Proof is in the solution. BTW where is the crack specifically? (wondering where all that pressure is going)

Sorry for reviving this old thread just wanted to tie up some loose ends. What caused the crack/damage on the cylinder head was an incorrect injector retaining bracket bolt. SKU: BMW-13537545904 Our indy mechanic used another bolt that was slightly larger when doing a valve cover gasket job. (he took off the injectors to see if any oil had seeped into the injectors) The BMW service manager said the bolt "punctured the crankcase" and cause the damage to the cylinder head. The bolt sits right in the middle of 2 injectors, I'm not sure where the pressure would be going, I haven't taken off the cylinder head to see though. And since BMW never took any pictures or anything I never saw the crack/damage myself. I'm kind of just taking their word for it and it makes sense. The car has good compression and the oil has no flakes. The car has just been sitting ever since. I'm a college student so I don't have the time, money, or motivation to fix it anymore. It sucks that a $4 part destroyed this car but oh well.

 

[RuskiRacer]

D

Sorry for reviving this old thread just wanted to tie up some loose ends. What caused the crack/damage on the cylinder head was an incorrect injector retaining bracket bolt. SKU: BMW-13537545904 Our indy mechanic used another bolt that was slightly larger when doing a valve cover gasket job. (he took off the injectors to see if any oil had seeped into the injectors) The BMW service manager said the bolt "punctured the crankcase" and cause the damage to the cylinder head. The bolt sits right in the middle of 2 injectors, I'm not sure where the pressure would be going, I haven't taken off the cylinder head to see though. And since BMW never took any pictures or anything I never saw the crack/damage myself. I'm kind of just taking their word for it and it makes sense. The car has good compression and the oil has no flakes. The car has just been sitting ever since. I'm a college student so I don't have the time, money, or motivation to fix it anymore. It sucks that a $4 part destroyed this car but oh well.

Lol bmw is really getting desperate these days huh