[shervi]

Hi All

Not used to posting, more used to searching, but if I had any hair to pull, I would pull it out now. So hopefully I am posting this in the right section. I saw a few other related questions in this forum, but it seems all those answers did not help

So I am have an n55 2013 EWG (m135). It has been running rich for a while. The car drives beautifully except for a couple of hiccups here and there related to fuelling.

Here are 3 datalogs I did the other day while on a stage 2 bootmod map. On the standard map, i still get close to the same results. But if it makes things easier I can revert to the stock tune and do another datalog. I live in Sydney, and where I am at there aren't many long roads to do some datalogs but if thats needed I can over the weekend.

So far I have changed
* Injectors (coded as well)
* had an AFE induction kit, but now back to standard air filter kit
* Coil pack
* MAF and map sensor
* Downpipe (thought it was a blocked cat)
* Pre and post sensor
* valve cover
* turbo inlet pipe
* car has an upgraded charge pipe


Datalogs

https://www.bootmod3.net/log?id=6655...c70e1310e889cf

https://www.bootmod3.net/log?id=6655...c70e1310e889d5

https://www.bootmod3.net/log?id=6655...c70e1310e889e0



Thanks in advance for your help!

[thejeremyman9]

Cant really tell anything in those logs. Need a WOT 3rd/4th gear pull to see. At idle the STFTs looked minor so i assume you are talking about under boost, so we definitely need those logs.

[shervi]

The STFT looks ok, because its already handed it over to the LTFT. The LTFT goes to around -30% and stays there, and then the STFT just does its minor adjustments.

To give you an idea, if I reset adaptations, the STFT sits at -30%, and with LTFT at 0. Then, within minutes LTFT goes to -30% and STFT starts to look normal.


Still want the 3/4th pull WOT, would it provide you with more info? If so, I can do it over the weekend.

Originally Posted by thejeremyman9

Cant really tell anything in those logs. Need a WOT 3rd/4th gear pull to see. At idle the STFTs looked minor so i assume you are talking about under boost, so we definitely need those logs.

[n55david]

Originally Posted by shervi

The STFT looks ok, because its already handed it over to the LTFT. The LTFT goes to around -30% and stays there, and then the STFT just does its minor adjustments.

To give you an idea, if I reset adaptations, the STFT sits at -30%, and with LTFT at 0. Then, within minutes LTFT goes to -30% and STFT starts to look normal.


Still want the 3/4th pull WOT, would it provide you with more info? If so, I can do it over the weekend.

Yes, do a wot log.. 3rd gear from about 3000rpm to 6500-7000 and 4th gear too if possible.. at the very least if you can shift to the and run through it too it would be helpful.

Please do it by first holding down the traction button to shutoff dynamic traction control by holding it for however long it takes, 3 or 4 seconds I believe.

[shervi]

So I switched off traction control and went from standstill to 5/6 where I could.

https://www.bootmod3.net/log?id=665b...62d16a7f179256
https://www.bootmod3.net/log?id=665b...62d16a7f179257
https://www.bootmod3.net/log?id=665b...62d16a7f179258
https://www.bootmod3.net/log?id=665b...33452a440f29e5

I've only just noticed you asked specifically 3rd wot from around 3000 rpm. I didn't put it in manual mode, but I do remember using sports for a couple of them, so hopefully it revved high enough.

If these aren't good enough, I will have to go back and do it again. Let me know.

Cheers

[thejeremyman9]

I skimmed a few logs. I see the LTFT corrections now. Together they are around -30%. Have you tried driving/logging briefly with the MAF unplugged?

Just thinking through it - if LTFTs are 0 and STFTs are -30 the car *thinks* (via O2 sensor reading lower AFR than target) it is running rich, so its pulling fuel. So either car is actually running rich, or O2 sensor is incorrect. It sounds like you replaced O2 sensor so if we assume car is actually running rich then it metered more air than actually made it to the engine, suggesting you leaked out metered air. Or, the MAF sensor readings were incorrect. If we assume MAF is correct then you might have a boost leak.

Unplugging the MAF would take it out of the equation and you can see what the STFTs do.

[harkes]

I noticed that your STFT is pegged at 1 for a big part of your pull. This usually means that car is running in open-loop. I remember having this problem also years ago but never found an answer to why...

I suggest you smoke test the engine to find vacuum/pressure leaks. I found this area on my intake pipe to be broken causing problems (might not be related to yours) so changed that and the PCV hose.

[Mdilo]

Did you ever find a fix for the high -LTFT?

[shervi]

Originally Posted by Mdilo

Did you ever find a fix for the high -LTFT?

Hey

Sorry for the late reply. No I did not get to the bottom of this unfortunately. I gave it to my mechanic. He works on performance BMW's but he could not figure it out. They ended up remapping the car and decreasing the fuel by 25% across the range. it's not ideal and annoyed me greatly. However I have come into some financial trouble, so just halted all work on the car for the moment.

I will revisit it at some point, but if you or anyone gets to the bottom of this, I am ALLL ears!

Whats the problem on yours?

[shervi]

Originally Posted by harkes

I noticed that your STFT is pegged at 1 for a big part of your pull. This usually means that car is running in open-loop. I remember having this problem also years ago but never found an answer to why...

I suggest you smoke test the engine to find vacuum/pressure leaks. I found this area on my intake pipe to be broken causing problems (might not be related to yours) so changed that and the PCV hose.

FYI, I think this is promising, I will try a leak test when I can next. I will respond if I find anything. Too many of these LTFT posts just end up abandoned.

[wheela]

Originally Posted by shervi

Hey

Sorry for the late reply. No I did not get to the bottom of this unfortunately. I gave it to my mechanic. He works on performance BMW's but he could not figure it out. They ended up remapping the car and decreasing the fuel by 25% across the range. it's not ideal and annoyed me greatly. However I have come into some financial trouble, so just halted all work on the car for the moment.

I will revisit it at some point, but if you or anyone gets to the bottom of this, I am ALLL ears!

Whats the problem on yours?

I'm on mhd so I didn't review the logs, but if you've swapped O2's, MAF, already and rule those out, what's left is fuel injection. Injectors won't overflow baseline, except if your rail sensor is reading incorrectly. Idle fuel pressure is not very high, so if your rail sensor reads low, your hpfp could be putting alot more pressure to the rail than it thinks. This would cause your injectors to dump more fuel than anticipated by the DME, causing rich condition and negative fuel trim to correct. Remapping is just a bandaid - I'd go back to old tune and try replacing your rail sensor. Good luck!

[shervi]

Originally Posted by wheela

I'm on mhd so I didn't review the logs, but if you've swapped O2's, MAF, already and rule those out, what's left is fuel injection. Injectors won't overflow baseline, except if your rail sensor is reading incorrectly. Idle fuel pressure is not very high, so if your rail sensor reads low, your hpfp could be putting alot more pressure to the rail than it thinks. This would cause your injectors to dump more fuel than anticipated by the DME, causing rich condition and negative fuel trim to correct. Remapping is just a bandaid - I'd go back to old tune and try replacing your rail sensor. Good luck!

I thought the same. I had the fuel rail pressure sensor changed when I gave it to the mechanic

[shervi]

I know its been a while, but this is here in case anyone else comes across the same problem.

So after much messing around, and you can see the changes I made to the car, I was pulling my hair out. Finally I put the above datalogs into Chatgpt with lots of other information. It turns out my target fuel pressure and then commanded fuel pressure was off by 2 bars, 2 bars higher! This resulted in the injection of more fuel per each opening cycle commanded by the ECU.

I have bootmod3, which you can choose the injectors you have if they are nostrum injectors or standard injectors. I chose Nostrum stage 2. This meant the map was adjusted for a higher delivery of fuel based on that injector profile.

After 2 days of testing, I noticed that the short term fuel trim and long term fuel trim where within the right margins, and there was no other issues including driveability issues.

My next question is why my bosch hpfp is pressurizing at a higher rate then normal. Do I keep it, or change it. Anyone with any experience in this area is welcome to chime in, as I don't know if I should fix it, or keep it and enjoy the boost

I will start another thread to see what others think.