[tallboy]

When the HPFP is doing that big dip below target, the AFR is quite rich (less than 11:1) and when the pressure get close to target is leans out a bit. Maybe the air/fuel mixture isn't getting burned and its dumping the raw mixture on the o2 causing it to measure rich?

I am currently having the same issue on my car with 3 different OTS maps in bootmod3 but stock map runs fine. Could you try logging your spark dwell time? I've noticed a big correlation between coil dwell times less than .5msec and a bad missfire/stutter. Stock dwell times rarely ever go below .5msec.

[thejeremyman9]

Originally Posted by tallboy

When the HPFP is doing that big dip below target, the AFR is quite rich (less than 11:1) and when the pressure get close to target is leans out a bit. Maybe the air/fuel mixture isn't getting burned and its dumping the raw mixture on the o2 causing it to measure rich?

I am currently having the same issue on my car with 3 different OTS maps in bootmod3 but stock map runs fine. Could you try logging your spark dwell time? I've noticed a big correlation between coil dwell times less than .5msec and a bad missfire/stutter. Stock dwell times rarely ever go below .5msec.

Correct me if I am wrong, but i am pretty sure misfires will result in a lean reading on the O2 sensor due to the unburnt oxygen in the exhaust, regardless of how much fuel is there. They measure oxygen, not fuel

[AmuroRay]

Originally Posted by tallboy

When the HPFP is doing that big dip below target, the AFR is quite rich (less than 11:1) and when the pressure get close to target is leans out a bit. Maybe the air/fuel mixture isn't getting burned and its dumping the raw mixture on the o2 causing it to measure rich?

I am currently having the same issue on my car with 3 different OTS maps in bootmod3 but stock map runs fine. Could you try logging your spark dwell time? I've noticed a big correlation between coil dwell times less than .5msec and a bad missfire/stutter. Stock dwell times rarely ever go below .5msec.

Stock coils and plugs, but I don’t know how to measure that. I’ll be upgrading to 328i plugs with a .22 gap here soon.

The problem I think, points towards a weak pump though.

[tallboy]

Originally Posted by thejeremyman9

Correct me if I am wrong, but i am pretty sure misfires will result in a lean reading on the O2 sensor due to the unburnt oxygen in the exhaust, regardless of how much fuel is there. They measure oxygen, not fuel

That actually makes perfect sense. I had never looked up how they worked before. So it it looks like its actually consuming more of the oxygen through the burn process. Still weird for it to be rich with the HPFP dipping like that.

[thejeremyman9]

Originally Posted by tallboy

That actually makes perfect sense. I had never looked up how they worked before. So it it looks like its actually consuming more of the oxygen through the burn process. Still weird for it to be rich with the HPFP dipping like that.

I just took a quick look at the logs. Do you think it might be commanding too much fuel, causing the HPFP to crash? It seems like the AFR goes rich at the exact moment the HPFP pressure starts to dip. I don't know why the tune would be doing that, but that is sure what it looks like.

OP - You seem to be missing a lot of parameters. I think you need to do more logs with, at a minimum, lambda target afr added in. Then we can see for sure if for some reason the target AFR dips, causing it to go rich and the HPFP crash, or if it just goes rich without a target AFR drop.

[AmuroRay]

Originally Posted by thejeremyman9

I just took a quick look at the logs. Do you think it might be commanding too much fuel, causing the HPFP to crash? It seems like the AFR goes rich at the exact moment the HPFP pressure starts to dip. I don't know why the tune would be doing that, but that is sure what it looks like.

OP - You seem to be missing a lot of parameters. I think you need to do more logs with, at a minimum, lambda target afr added in. Then we can see for sure if for some reason the target AFR dips, causing it to go rich and the HPFP crash, or if it just goes rich without a target AFR drop.

Understood. I’ll try to have everything turned on.

[zole2112]

Originally Posted by Munchi435i

How often do you datalog your car?

Any current logs you can share for comparison?

I can log it this weekend, out of town until Fri. I'll post a couple of logs for comparison.

[AmuroRay]

SeanWRT - I saw you commenting on another thread about these issues. Thoughts?

[435gc]

Originally Posted by zole2112

You have the same HPFP as me, stock turbo (mine is 335xi, don't know if we have the same turbo but mine is stock) and I am running JB4 Map 7 and MHD with BMS Race BEF, I run e50-e60 I am FBO and I have no issue with fueling so I don't believe you are maxing out your HPFP if I'm not unless I'm missing something, which I may be.

Love to see logs for this.

[zole2112]

Originally Posted by 435gc

Love to see logs for this.

Here's 1 log, had to find a good stretch of road but here's a wot gear 3/4/5
https://datazap.me/u/zole2112/102719...log=0&data=1-4

[NOTANM4]

I'm currently running Stage 2+E20 mix from MHD Tuning and it's been great but as of recent i've been getting fuel cuts, and as time passes they get more significant, i've adjusted my mix, re flashed and I do see the fuel rail pressure drop on WOT usually 3rd, 4th and 5th gear are the terrible, I live in CA so I only have 91, I ONLY use Shell 91 V power with the (new formula) i've heard from multiple people shell is better than chevron... anyways I attempted to remove the filter from my HPFP for more flow, i've heard of many N54 owners running like this for years w/ all fuel filters taken out except one LPFP filter, and 1 owner with NONE and has had no issues for years and is showing improved flow, I was looking just to remove mine but I was unsuccessful I seen the filter on the "inlet" side of the HPFP but it looks like it's maybe glued in... i was able to take a clean pick tool and poke a hole in the side of the "mesh" of the fuel filter hopefully this will improve some flow...

[Munchi435i]

Originally Posted by zole2112

Here's 1 log, had to find a good stretch of road but here's a wot gear 3/4/5
https://datazap.me/u/zole2112/102719...log=0&data=1-4

Looks like your off target boost by about 3psi through the entire log, boost leak?

[thejeremyman9]

Originally Posted by Munchi435i

Looks like your off target boost by about 3psi through the entire log, boost leak?

Having just gone through the same thing, it does seem like a boost leak; that's quite a bit off target. Even when i had a leak, i was able to reach target by the top of 4th and throughout 5th.

[zole2112]

Originally Posted by Munchi435i

Looks like your off target boost by about 3psi through the entire log, boost leak?

I don't think so, always been like that with no real variation from that. If there was a boost leak it would be more variable than that. Had my logs checked multiple times from Terry, always said they looked good with no issues.

[thejeremyman9]

Originally Posted by zole2112

I don't think so, always been like that with no real variation from that. If there was a boost leak it would be more variable than that. Had my logs checked multiple times from Terry, always said they looked good with no issues.

My boost leak was not variable at all. I could do logs back to back, then log a different day, etc, they all exhibited pretty much exactly the same behavior, same curve, and same deviation from target. Unless your boost leak is somehow changing over time, i wouldnt expect it to be variable?

It may not be a boost leak, but is there another reason you are pretty far from target? I dont see a way to check actual load vs. target load in your log to compare those

[Munchi435i]

Originally Posted by zole2112

I don't think so, always been like that with no real variation from that. If there was a boost leak it would be more variable than that. Had my logs checked multiple times from Terry, always said they looked good with no issues.

Why not just go full flash?

JB4 was a great solution before full flashing became available but to each their own.

But being off target by 1psi or so is considered common but yours seems pretty off. Also, yes would be great to see the target load and actual load to compare more data points.

[AmuroRay]

Not to be rude guys, but this thread isn’t about boost leaks, I was/am looking for advice on my dueling issues.

[zole2112]

Originally Posted by thejeremyman9

My boost leak was not variable at all. I could do logs back to back, then log a different day, etc, they all exhibited pretty much exactly the same behavior, same curve, and same deviation from target. Unless your boost leak is somehow changing over time, i wouldnt expect it to be variable?

It may not be a boost leak, but is there another reason you are pretty far from target? I dont see a way to check actual load vs. target load in your log to compare those

I'm going to check into it I think, I started researching yesterday and I will have it up on a lift in the next couple of weeks. Thanks man, I appreciate the info!

[zole2112]

Originally Posted by AmuroRay

Not to be rude guys, but this thread isn’t about boost leaks, I was/am looking for advice on my dueling issues.

You are absolutely right, sorry about the thread hijack. Anyway, I don't think you will exceed the stock HPFP capability with a stock turbo unless you went too high on ethanol content.

[thejeremyman9]

Originally Posted by zole2112

I'm going to check into it I think, I started researching yesterday and I will have it up on a lift in the next couple of weeks. Thanks man, I appreciate the info!

Cool, interested to see what you find; you can PM me if you don't want to go off topic here

Originally Posted by AmuroRay

Not to be rude guys, but this thread isn’t about boost leaks, I was/am looking for advice on my dueling issues.

Sorry about that, we went off topic. Going back to my suggestion from a few days ago, were you able to get any new logs with more parameters included? I think we really need to see why your AFRs dip into the 10s at the same exactly time the HPFP crashes. Basically, we need to see if that AFR was targeted, or if it went rich for another reason, because it seems like the HPFP crashed while trying to supply too much fuel. You mentioned a custom tune, but i haven't seen any tune that targets AFRs in the 10s on these cars. If this started right after the tune, its possible the target AFR is off for some reason? We need the data to see.

It would be helpful to just turn on nearly all parameters (I think i only unchecked a few) and then do some more logs. High load, high RPM, and low ambient/IAT would probably be the situation where the HPFP crashes.

[tallboy]

If you flash your stock tune, then flash the custom tune, does it still do it? I ask because when you flash tunes, it resets you LTFT and I've noticed that temporarily fixes my issue. Reseting adaptations does not reset my LTFT(at least not in bootmod3).

But like you my tune ran well for a few days (when my LTFT is 1.00) then a few days later it is 1.15 or above, runs really rich and stumbles at high throttle. My logs also show a HPFP dip below target when this occurs. Stock flash has no problem. I think MHD logs it as a percentage though. So your LTFT would be something like +20% instead of 1.20

I'm starting to suspect it's heat related. When EGTs get really high, the DME will richen up the mixture to try and keep things cool. There are no EGT sensors on our motors so its actually a calculated value but mine gets to around 1950F pre turbo and 1450F post turbo. I wonder if your logs show anything similar

[Ajax915]

Originally Posted by zole2112

What codes did it throw? when my HPFP was going out it gave me 110001, 11A031 and 11A002 for fuel pressure and also 193001 for fuel level sensor. No misfire codes

I have the same first 3 codes as you. I get the Drivetrain light but she starts up right after I restart her. Hasn’t stalled on me in 5 months. I notice it happens around 1/4 tank of gas. I was thinking the lpfp then replacing the hpfp. What were your symptoms ?