[pham]

Hi all,

First and foremost I'd like to apologize for the long read! I wanted to describe the problem in detail, the steps we've taken in attempts to mitigate the issue, and the results from start to finish.

Well, I might've made the same mistake again after my previous BMW blew a motor but I've purchased yet again another N54. This time a 2009 BMW 335i.

The Problem:

I have an indy guy that has been doing all the work and maintenance on it, however I have come across a pesky fuel mixture code that we've been unable to figure out for months now.

The car has been completely resealed with all new gaskets so no leaks. We've taken care of all of the maintenance prior to going full bolt ons. The car currently is on a OTS tune of MHD Stage 2+ V10 93 octane. Have tuned to older versions and stock, reset adaptations, without resolution.

The fuel mixture code 29e0 and 29e1 came on about a month after installing a set of used index 12 injectors due to the previous injectors being a mixture of index 5, 8, and a single index 12 injector where I was getting a lot of hesitation and the car was breaking up under boost.

The car ran great after the used index 12 injectors were put in. No misfires, no hesitation, but would get a check engine light with fuel mixture codes and high ltfts in the low to mid 20s.

The injectors were used but were cleaned, flow, and leak tested at a local shop here in Houston, Texas with a new internal filter and seals.

The thought was that the used index 12s were bad so I put back in the old mixture of 5, 8, and 12 injectors that never had the fuel mixture code prior just had hesitation at full boost but still the issue persisted with the fuel mixture code following.

We then got another set of index 12s, took them to a different local shop, and again had them cleaned, flow, and leak tested with new seals and put them in the car. Still extremely high fuel trims. Drivability and power wise, no issues. Drives through the city and pulls with plenty of power without issue.

The injectors were coded to the car each time a different set of injectors were swapped in.

However, upon examination of the fuel trims, I've noticed low to mid 20s on ltfts at highway crusing above 60 mph. And mid 10s to low 20s at city driving under 60 mph. The ltfts jump up as soon as any acceleration is applied but drops as soon as I let off of the accelerator.

We've done a smoke and leak test on the entire vehicle and wasn't able to locate any leaks. No boost leaks, no vaccum leaks, and no leaks were found in the exhaust system.

Modifications and Parts Changed:

Full bolt ons with VRSF downpipe, fmic, BMS chargepipe, Tial BOV, VRSF dual cone intake

Fresh oil change

Coolant flush

Vanos solenoids cleaned

Stock turbos - we believe are on its way out. Still boosting fine but has some wastegate rattle and a little bit of smoke at idle.

New vaccum lines - prior to fuel mixture code

Oil catch can with an aftermarket pcv valve due to the stock pcv valve clips breaking. Thought the fuel mixture code was due to the pcv valve popping off, however after replacing it with an aftermarket one, the fuel mixture code still persisted

New boost solenoids (replaced due to overboost codes, fixed overboost issue) - prior to fuel mixture code

All 4 new oxygen sensors - prior to fuel mixture code

New valve cover and gasket - prior to fuel mixture code

NGK 1 Step Colder Plugs

Eldor Ignition Coils

Walnut Blast

New low pressure fuel pump - Precision Raceworks stage 2.5 v2 pump (after we observed low fuel pump values) - after fuel mixture code, however
did not resolve our fuel mixture code issue

Precision Raceworks upgraded in tank fuel regulator - after fuel mixture code, however did not resolve our fuel mixture code issue

New downpipe gaskets (due to leak found in exhaust) - after fuel mixture code, however did not resolve our fuel mixture code issue

Cleaned MAP sensors on charge pipe and on the intake manifold - after fuel mixture code, however did not resolve our fuel mixture code issue

Data Logs:

I've attached several logs in different settings to showcase the ltfts reacting at different speeds below.

3rd Gear Pull:

https://datazap.me/u/howardpham/3rd-...og=0&data=3-23

Highway Crusing > 60 Mph:

https://datazap.me/u/howardpham/high...og=0&data=3-23

City Driving < 60 Mph:

https://datazap.me/u/howardpham/city...og=0&data=3-23

Normal Driving Gears 1 - 6 From Stop:

https://datazap.me/u/howardpham/norm...og=0&data=3-23

Conclusion:

What we know:

The car runs perfect, boosts fine, and without hesitation or misfires.

Fuel mixture code 29e0 and 29e1 appear after a long highway drive. Which we noted that when we are crusing above > 60 mph the ltfts peg 20-25%. And city driving below < 60 mph results in ltfts lower at approximately 15-20%. With ltfts immediately dropping to 10% and sometimes even lower after the throttle is let off.

At this point, we've exhausted all efforts and I'm hoping anyone who would be able to guide us in the right direction or provide some input on any suggestion or solution. Thank you for taking your time in reading my thread!

Update:

Update: We've performed another smoke test but this time we pressurized the system which revealed a leak coming from the back of the valve cover.

It seems that a leak was only present under certain conditions. Therefore, it did not reveal itself until we introduced some pressure into the system.

We're unsure if the valve cover itself has failed or the gasket. None the less, we're getting the replacement part guarantee from FCP Euro and will be putting the new one on next week and hoping it fixes our issue.

While we're doing the valve cover replacement again, I've decided that while we're in there we'd block off the head ports and do an external pcv system while we're at it.

I'll update with the results as to whether or not our valve cover resolves our issue. Thank you both!

Update #2:

Update #2: We've finished replacing the valve cover and gasket just yesterday. In addition to the valve cover, we also blocked off the head ports and added the RB N54 External PCV Kit.

After an initial idle, the ltfts dropped to around 6% from the previous high 20s. I'd assume that number may drop a tad bit more after driving around for a bit and letting the computer readjust.

N54 Head Port Block Off Kit:

View post on imgur.com

RB N54 External PCV Kit:

View post on imgur.com

Update #3:

Update #3: Unfortunately the valve cover replacement did not offer a long term solution to my problem. The ltfts eventually returned to its high values of 20% on both banks. It's now back to the drawing board now to figure out what the issue may be.



Update #4:

Update #4: I've taken the car to a different shop and they ended up removing the downpipes and inspecting it for any cracks and/or leaks.

Upon removing the downpipes, they had found that the downpipes were in fact leaking and was cracked at the turbo flange.

For now, I've brought them a second set of downpipes I had and they'll be installing it later today. I'll update to whether or not the downpipes resolve my issue.

View post on imgur.com

[Sgop335]

lot to read, have the injectors CODED correctly?

[pham]

Originally Posted by Sgop335

lot to read, have the injectors CODED correctly?

Yes, the injectors have been coded each time a different set was put in with the adaptations reset. However, the high fuel trims return after some highway driving at speed.

I apologize for the long read! I wanted to describe the problem in detail, the steps we've taken in attempts to mitigate the issue, and the results from start to finish.

Thank you for taking your time in replying to my issue!

[Sgop335]

Saying o2 sensors are replaced, oem bosch? Any other codes?
How much e85 in the fuel?

Looks like classic low fuel scalars / fuel injectors not sending enough fuel especially at part load. 3rd gear pull seems ok. Stfts are still little high. Good part both banks seem to follow for both long term and short term. This can be easily fixed by increasing fuel scalars in a custom tune, however why should you, right? Especially if its not an ethanol blend or is it?

[pham]

Originally Posted by Sgop335

Saying o2 sensors are replaced, oem bosch? Any other codes?
How much e85 in the fuel?

Looks like classic low fuel scalars / fuel injectors not sending enough fuel especially at part load. 3rd gear pull seems ok. Stfts are still little high. Good part both banks seem to follow for both long term and short term. This can be easily fixed by increasing fuel scalars in a custom tune, however why should you, right? Especially if its not an ethanol blend or is it?

All 4 o2 sensors were replaced with oem Bosch from FCP Euro. No E85, just the standard 93 octane we get here in Texas. No other codes beside the shadow codes 29F4, 29F5, 2AAF, 2FCA, 2FDA. All of which existed months prior to the fuel mixture code.

I've thought about a custom tune as well. I actually reached out to Ken from Wedge Performance as he previously tuned my old car back in 2017. However, he believes that it may be a leak in the intake system or the exhaust at the downpipes that may be introducing unmetered air.

Although we have already smoke tested the intake and exhaust and found no leaks. There was a previous leak at the downpipe gasket, but we had replaced the gasket and resmoked with no leaks but the issue still persisted with the fuel mixture codes.

I think we'll just give it another try at resmoking the entire car again to see if we find anything new.

[Sgop335]

If theres a leak, probably at the intake manifold post throttle body. Especially affects engine part load or vacuum, where trims are high.

[Cmanns05]

Those codes are lean conditions pretty simple.

Its both banks so unlikely to be an injector or o2.

Reduce your tune, stock or stage 0.

1a. Check STFT make sure they track together and aren't huge numbers.
1b. Check rail and LPFP pressure

Check for boost leaks

Update after

[pham]

Update: We've performed another smoke test but this time we pressurized the system which revealed a leak coming from the back of the valve cover.

It seems that a leak was only present under certain conditions. Therefore, it did not reveal itself until we introduced some pressure into the system.

We're unsure if the valve cover itself has failed or the gasket. None the less, we're getting the replacement part guarantee from FCP Euro and will be putting the new one on next week and hoping it fixes our issue.

While we're doing the valve cover replacement again, I've decided that while we're in there we'd block off the head ports and do an external pcv system while we're at it.

I'll update with the results as to whether or not our valve cover resolves our issue. Thank you both!

[Sgop335]

guess the way "valve cover leak" could affect your fuel trims is thru the PCV ports?
that way the intake manifold vacuum may pull unmetered air (actually should say unthrottled air)..or leak at boost...

[Cmanns05]

Hows the car doing? Wouldn't that leak work both ways though? Fluid and air would escape? Is there a physical fluid leak as well?

[pham]

Update #2: We've finished replacing the valve cover and gasket just yesterday. In addition to the valve cover, we also blocked off the head ports and added the RB N54 External PCV Kit.

After an initial idle, the ltfts dropped to around 6% from the previous high 20s. I'd assume that number may drop a tad bit more after driving around for a bit and letting the computer readjust.

N54 Head Port Block Off Kit:

View post on imgur.com

RB N54 External PCV Kit:

View post on imgur.com

[pham]

Update #3: Unfortunately the valve cover replacement did not offer a long term solution to my problem. The ltfts eventually returned to its high values of 20% on both banks. It's now back to the drawing board now to figure out what the issue may be.

[Aode06]

Show us the fuel injectors you bought very clear pictures with part numbers.

[pham]

Originally Posted by Aode06

Show us the fuel injectors you bought very clear pictures with part numbers.

Here's a couple of photos of the fuel injectors I had purchased with the part numbers. As well as a photo of the injector test results from a local injector shop.

[Sgop335]

Have done business w Fuel 1 in houston. Recommended!

As mentioned likely have a post throttle body leak

[pham]

Update #4: I've taken the car to a different shop and they ended up removing the downpipes and inspecting it for any cracks and/or leaks.

Upon removing the downpipes, they had found that the downpipes were in fact leaking and was cracked at the turbo flange.

For now, I've brought them a second set of downpipes I had and they'll be installing it later today. I'll update to whether or not the downpipes resolve my issue.

View post on imgur.com