[AU335i]

Hey guys was wondering if you could help diagnose an issue for me.

My car is a 2008 335i 6MT FMIC/DP/DCI and has 37k miles on it. When running Procede Aggressive Stage 3 Map 1 I notice at WOT when my gauges are reading AFR the gauge spikes lean then finally goes to mid 12's around 4k rpm... someone before told me I may have a slight misfire but I have no codes besides the catless DP codes. MY gas mileage has also been horrible... averaging ~14-15(sometimes 12-13) city and ~27 mpg interstate... this is with tune on or stock map loaded. it doesn't make a difference I get bad gas mileage even if I'm driving like a grandma through city.

Do you think my spark plugs need to be replaced? I replaced them back at 22k miles so I've been about 15k tuned-miles on the current set.

Like i said i'm not gettting any car shuttering misfires or codes or ses lights. Was talking with some friends tonight and wondered could it possibly be a failing LPFP or HPFP? I checked through a BT Cable on the stock tune earlier tonight and "Fuel Low Pressure Sensor" parameter read 72 psi(~5000 hPa) (which is normal IIRC).

I've attached some old logs that show what I'm talking about with the AFR. DL 1 is with OL fueling set to 85 and DL 2 is with OL fueling set to 100.

A member on here told me tiny lean spikes at the onset of boost are very indicative of either a misfire or an issue with the injectors. I recently replaced all the injectors to the 261 P/N and coded it all correctly myself. So I don't think it is the injectors.

Any help is much appreciated. Thank you!

[AU335i]

bump. anyone?

[SharkBait]

Since no one else has bitten yet, I'll throw in my 0.02 even though I have yet to tune an N54. If your AFR is spiking, it could be a fuel supply issue but equally it could be a spark issue causing unburnt fuel to wash over the O2 which will then read a false lean. Are you getting any popping noises out of your exhaust? Since your plugs are old, get a new set. They're probably due for replacement and they're cheap.

[AU335i]

Originally Posted by SharkBait

Since no one else has bitten yet, I'll throw in my 0.02 even though I have yet to tune an N54. If your AFR is spiking, it could be a fuel supply issue but equally it could be a spark issue causing unburnt fuel to wash over the O2 which will then read a false lean. Are you getting any popping noises out of your exhaust? Since your plugs are old, get a new set. They're probably due for replacement and they're cheap.

thanks for the reply.

and actually, yeah whenever I have the tune on and its semi-cold i get crazy pops/backfires... they can get loud on cold starts.

but O2 sensors only have 37k miles... do they go bad over time regardless of mileage?

[TenshiWingusu]

Originally Posted by AU335i

Hey guys was wondering if you could help diagnose an issue for me.

My car is a 2008 335i 6MT FMIC/DP/DCI and has 37k miles on it. When running Procede Aggressive Stage 3 Map 1 I notice at WOT when my gauges are reading AFR the gauge spikes lean then finally goes to mid 12's around 4k rpm... someone before told me I may have a slight misfire but I have no codes besides the catless DP codes. MY gas mileage has also been horrible... averaging ~14-15(sometimes 12-13) city and ~27 mpg interstate... this is with tune on or stock map loaded. it doesn't make a difference I get bad gas mileage even if I'm driving like a grandma through city.

Do you think my spark plugs need to be replaced? I replaced them back at 22k miles so I've been about 15k tuned-miles on the current set.

Like i said i'm not gettting any car shuttering misfires or codes or ses lights. Was talking with some friends tonight and wondered could it possibly be a failing LPFP or HPFP? I checked through a BT Cable on the stock tune earlier tonight and "Fuel Low Pressure Sensor" parameter read 72 psi(~5000 hPa) (which is normal IIRC).

I've attached some old logs that show what I'm talking about with the AFR. DL 1 is with OL fueling set to 85 and DL 2 is with OL fueling set to 100.

A member on here told me tiny lean spikes at the onset of boost are very indicative of either a misfire or an issue with the injectors. I recently replaced all the injectors to the 261 P/N and coded it all correctly myself. So I don't think it is the injectors.

Any help is much appreciated. Thank you!

This is EXACTLY what is happening with mine on the stage 1 maps, and I have not found much help on the forum.. Can you do two things for me.

1. Send/post the logfile so I can do direct data comparison
2. Do a log with the channels Fuel Pressure and CAN Fuel Pump PWM and post it

My suspicion is two things at this point. The PROcede might use a closed loop PWM control for the LPFP, cant confirm this. SO either the Low pressure fuel sensor ($80) is incorrectly reading high and thus causing boost onset to not have enough flow rate or the pump itself is starting to wear out. What I hope you find when you relog is that the PROcede throws in a huge GOB of LPFP PWM duty cycle (up to 100% in my case) after it sees it the spike to keep up with the AFR demands which is why towards the end of the pull the fuel trims drop into the negatives because there is now too much fuel.

Relog and post it. I've been looking for comparative data for months.... If anyone else who reads this and has a PROcede car that runs great, if you could log with those two channels I would love to see what they are supposed to look like.

[SharkBait]

Originally Posted by AU335i

thanks for the reply.

and actually, yeah whenever I have the tune on and its semi-cold i get crazy pops/backfires... they can get loud on cold starts.

but O2 sensors only have 37k miles... do they go bad over time regardless of mileage?

Your O2 sensors are probably OK. A normal working O2 sensor will false lean when washed in fuel. However, if you keep soaking it in fuel, it will eventually foul and malfunction. Sounds like you have some spark blow out. Change your plugs, gap them as needed, and report back.

[TenshiWingusu]

Originally Posted by SharkBait

Your O2 sensors are probably OK. A normal working O2 sensor will false lean when washed in fuel. However, if you keep soaking it in fuel, it will eventually foul and malfunction. Sounds like you have some spark blow out. Change your plugs, gap them as needed, and report back.

Just a note, I have brand new plugs and I still have this issue.

[SharkBait]

Originally Posted by TenshiWingusu

Just a note, I have brand new plugs and I still have this issue.

Do you have the same backfire/popping? If so, maybe a bad or weak coil pack.

[AU335i]

Originally Posted by TenshiWingusu

This is EXACTLY what is happening with mine on the stage 1 maps, and I have not found much help on the forum.. Can you do two things for me.

1. Send/post the logfile so I can do direct data comparison
2. Do a log with the channels Fuel Pressure and CAN Fuel Pump PWM and post it

My suspicion is two things at this point. The PROcede might use a closed loop PWM control for the LPFP, cant confirm this. SO either the Low pressure fuel sensor ($80) is incorrectly reading high and thus causing boost onset to not have enough flow rate or the pump itself is starting to wear out. What I hope you find when you relog is that the PROcede throws in a huge GOB of LPFP PWM duty cycle (up to 100% in my case) after it sees it the spike to keep up with the AFR demands which is why towards the end of the pull the fuel trims drop into the negatives because there is now too much fuel.

Relog and post it. I've been looking for comparative data for months.... If anyone else who reads this and has a PROcede car that runs great, if you could log with those two channels I would love to see what they are supposed to look like.

Hmm this makes sense. I had my LPFP sensor replaced recently though within the last year. but ill get a log to you when I find some time! Can you pm me your e-mail so I can send these datalog files to you directly?

[TenshiWingusu]

Originally Posted by SharkBait

Do you have the same backfire/popping? If so, maybe a bad or weak coil pack.

I have a horrible idle studder and sometimes a light studder on ~15-20% throttle. My exhaust pops from the flapper being unplugged. Most likely though I have 2 issues, one being the fueling (sensor or pump) the other having something to do with my #6 injector which doesn't throw codes or show any signs on the O2 logs... (but the plug looked very dirty and a bit black) CPO wont do anything about it, I got carbon cleaning and new plugs a month ago + their BS techron additive.

[AU335i]

Originally Posted by TenshiWingusu

I have a horrible idle studder and sometimes a light studder on ~15-20% throttle. My exhaust pops from the flapper being unplugged. Most likely though I have 2 issues, one being the fueling (sensor or pump) the other having something to do with my #6 injector which doesn't throw codes or show any signs on the O2 logs... (but the plug looked very dirty and a bit black) CPO wont do anything about it, I got carbon cleaning and new plugs a month ago + their BS techron additive.

LOL ok yeah we have an identical problem... my idle studders all the time as well and when i blip the throttle at idle the RPMS will drop below 500 and car will shudder... I dont think it's injectors cuz I replaced all mine and coded correctly myself.

[The Ghost]

Looking at your logs, your maps are too aggressive for your fuel. You are knocking on every run. Your boost is too high for pump and that much timing. I'm guessing you're running 91-93.

For reference, on 93 my car run 4-9 degrees of timing (ramped) and 14psi peak. On e85 or meth I can run way more without knock.

Also, you may need to raise your OL fueling a hair as your fuel trims appear to be near maxed-out (it's hard to tell, you have to move e cursor to the area at eak boost/tq).

You can also tweak the tip-in AFR spike via the OL fueling table. This is useful when you drag race a lot.

HTH

[AU335i]

Originally Posted by The Ghost

Looking at your logs, your maps are too aggressive for your fuel. You are knocking on every run. Your boost is too high for pump and that much timing. I'm guessing you're running 91-93.
For reference, on 93 my car run 4-9 degrees of timing (ramped) and 14psi peak. On e85 or meth I can run way more without knock.

Also, you may need to raise your OL fueling a hair as your fuel trims appear to be near maxed-out (it's hard to tell, you have to move e cursor to the area at eak boost/tq).

You can also tweak the tip-in AFR spike via the OL fueling table. This is useful when you drag race a lot.

HTH

hmm I'm running the Stage 3 Map 1 from PROcede which should be the right map for my mods and 91-93 pump gas. Alabama claims 93 octane but even if the quality is low would it be under 91? I can try running the Stage 2 or Stage 1 Maps and see if I get the same results I suppose...

What makes you say my car is knocking though? just curious

My OL fueling was 85 for the first log and 100 for the second

[TenshiWingusu]

Originally Posted by AU335i

hmm I'm running the Stage 3 Map 1 from PROcede which should be the right map for my mods and 91-93 pump gas. Alabama claims 93 octane but even if the quality is low would it be under 91? I can try running the Stage 2 or Stage 1 Maps and see if I get the same results I suppose...

What makes you say my car is knocking though? just curious

My OL fueling was 85 for the first log and 100 for the second

The sudden drops in timing in the OLF 85% log are in reaction to knock. They start to go away up at OLF 100% which makes me think its fueling related. You can probably drop your start boost % down 5-10% from where it is and it will band-aid it for now.

[The Ghost]

Originally Posted by AU335i

hmm I'm running the Stage 3 Map 1 from PROcede which should be the right map for my mods and 91-93 pump gas. Alabama claims 93 octane but even if the quality is low would it be under 91? I can try running the Stage 2 or Stage 1 Maps and see if I get the same results I suppose...

What makes you say my car is knocking though? just curious

My OL fueling was 85 for the first log and 100 for the second

The points where your ignition advance drops is definitely knock, your first run had two occurrences in the same gear pull. You want to fix this ASAP. Reduce timing 1 degree and drop boost 2psi and work up/down from there.

Every car is different, but mine would knock just like yours with that huge boost and your very advanced timing.

[Jeff@TopGearSolutions]

Originally Posted by The Ghost

The points where your ignition advance drops is definitely knock, your first run had two occurrences in the same gear pull. You want to fix this ASAP. Reduce timing 1 degree and drop boost 2psi and work up/down from there.

Every car is different, but mine would knock just like yours with that huge boost and your very advanced timing.

I agree. I would reduce the boost a touch. Then maybe look into adjusting the OL Fuel table for tip in and raising OL Fueling another 5%.

I would also atleast check the GAP on the spark plugs too if you dont want to change them just yet.

[TenshiWingusu]

Originally Posted by AU335i

LOL ok yeah we have an identical problem... my idle studders all the time as well and when i blip the throttle at idle the RPMS will drop below 500 and car will shudder... I dont think it's injectors cuz I replaced all mine and coded correctly myself.

Make sure when you do the data log you have the following channels

CAN Actual AFR Bank 1
CAN Actual AFR Bank 2
CAN Fuel Trim Bank 1
CAN Fuel Trim Bank 2
Throttle
Boost Control Set Point
Fuel Pressure
CAN Fuel Pump PWM
Debug Byte 4


Right off the bat after looking at your data logs you sent I think can see an issue. From what I've read elsewhere you don't want the LPFP voltage (debug byte 4) to drop below 2v. Besides boost onset it's always below 2v. I'm trying to get a hold of a friends car that runs perfectly to check his.