STFT Banks 1 & 2 - What is normal ?

[BuraQ]

Is it normal for STFT Banks 1 and 2 to be off from each other, and by how much is considered normal ?

http://www.datazap.me/u/buraq/beastm...ata=2-13-14-15

The only thing I found when searching was related to an M3 in which its STFT bank 1 was in the negative and bank 2 in the positive is has no relation to my concern.

Thanks in advance.....

[135pats]

That's a good deal more variance than you'd like to see, and pretty active trim adding throughout the log. What fuel are you running? You shouldn't be seeing bank 1 and 2 varying by more than a few units in either direction.

[BuraQ]

That's a good deal more variance than you'd like to see, and pretty active trim adding throughout the log. What fuel are you running? You shouldn't be seeing bank 1 and 2 varying by more than a few units in either direction.

E50, but the E85 here is sometimes more than E85 at the Shell stations that I frequent based on recent testing done by member @BoostAddict who is a local, and works on my car.

I was thinking of just upping the scalar area of concern for bank 2. Previously I had gotten a mixture code out of the blue but it never came back, so I upped the scalar on both banks as suggested by @SteveAZ . Bank 1 looks better than before but now that I am seeing bank 2 for the first time I see the reason I got the mixture code previously

[135pats]

It could be a faulty o2 as well. IMO both banks are too high on trim, ideally it would stay relatively flat and under 15-20 when the fuel request is highest.

[BoostAddict]

I didn't look at the log, but if there is a large variance between banks perhaps you have an injector that is failing.

[lulz_m3]

I have always considered <+/-5% to be ok if you are off meth.

[alex@ABRhouston]

I have always considered <+/-5% to be ok if you are off meth.

This is where I want to see trims. Even less, is fine by me. Once you get past that, you have issues with the DME freaking out.

And lets call them what BMW calls them, they aren't Chevys

Short trim: additives.
long trim: multiplicatives.

[stangorang]

Normal. I have tons of logs of a significant variance between the two banks on STFTs. I chased the issue by replacing the pre-cat O2 sensors and it made no difference. The injectors and HPFP are brand new as well. I reset ALL adaptations with the BT tool and INPA several times and it made no difference in the trims.

I wouldn't worry about it as long as the car is running fine and hitting AFR targets.

Both logs are OTS cobb e30 maps with changed scalars.
My scalar on the first log is around 1.25 in the 3K-4K RPM high load range. I forget what it is on the second but probably 1.15- 1.20

http://datazap.me/u/stangorang/fuel-scalar-3k-4k-fix-e30?log=0&data=1-16-17-22

http://datazap.me/u/stangorang/new-f...ata=1-16-17-22

[stangorang]

My LTFTs aren't exactly pretty either.

I looked for boost leaks, vacuum leaks, etc and never came up with anything.

[alex@ABRhouston]

If your additives and multiplicatives are way positive, then you need to adjust your base tune to make it more rich.
its not a hard thing to understand.


additives are in milliseconds. at idle its adding/subtracting XX in milliseconds to fuel injection pulse width.
multiplicatives are in percentage, which is under load and driving.... its adding/subtracting xx% over the entire fuel curve.

[V8Bait]

If your additives and multiplicatives are way positive, then you need to adjust your base tune to make it more rich.
its not a hard thing to understand.


additives are in milliseconds. at idle its adding/subtracting XX in milliseconds to fuel injection pulse width.
multiplicatives are in percentage, which is under load and driving.... its adding/subtracting xx% over the entire fuel curve.

Always wondered how BMW scaled trims... thank you for that little gem

[Steve@Fuel-It!]

I think part of this also has to do with the aging and natural degradation of the piezo crystals which isn't necessarily linear across all the injectors.

I too had a delta between the banks, swapped the injectors between banks one and two and the "problem" followed. Given it was pretty minimal and kind of a pain in the arse to chase...I lost interest and let it go.

If the delta got too large...I'd chase it. If its a single injector, that entire bank could be adjusted based on the performance of that one injector. If you got really anal about it...you could locate and re-cal the offending injector (provided it doesn't have an issue)..but it would be a PITA.

Your logs are fairly rich for e50...so not likely there is any real danger there...but your trims are high, I would definitely adjust them. However, you're not logging your long term trims...it'd be nice to see those as well.

[JoshBoody]

Another cause to consider is uneven WGs which will skew trims.

I think ST and LT are both in % (or could be volume)... can't be ms since pressure is also factored. ST is real time adjustment, LT is change to the base. GM ST is similar reference, but can use inj on time since pressure is constant. LT is an average of ST though.

[alex@ABRhouston]

Ok, you must be right, because your a master BMW tech, right?


Again, this aint a chevy.

[Aerotest]

Tech and engineer are two different things. Sometimes one tries to pose like the other.

[BuraQ]

Taking in consideration first what @stangorang "experienced" as he replaced hardware that would have had a direct affect on the problem if the hardware was faulty. However hardware was not the case. Similar experience from @SteveAZ , no matter what hardware changes were done the results were still the same.

For me I have 65K miles on my car, and the dealer replaced the injector with the newer ones when I was at 49k miles. It wasnt needed it was just something done I wouldnt have to worry about. My car does not sit, it is driven eveyday mostly highway milage

I have the orignal o2 sensors when I bought the car new. I am not cattless, I am running CP-e Highflow Catts with stock mid-catts. Mid-catts will be removed befor the end of the year. I doubt seriously a faulty o2 sensor is the issue, as my AFRs are perfectly on target

After increasing the scalar in the "cell range" where the concern is being had STFT bank 1 improved but I could not see bank 2. After logging STFT bank 2 that is where the major problem was and a significant gap between the two banks

So I raised the "cell range" of cocern in STFT bank 2 from 1.256-1.240 to 1.296-1.280 and the gap between the two banks was reduced

http://datazap.me/u/buraq/bestmode-3...ata=2-13-14-15

Now considering @alex@ABRhouston perspective, if I am not mistaken, making the process more rich should render positive affect on the trims. My trims start to max out at the "begining" of WOT. I asume the the DME looks at the Fuel (Spool) table first ? I will start with the Fuel (Spool) first in making it run more rich before the Fuel base takes over. The Cobb OTS table from its E30 map is more lean from the stock, so I am going to revert back to the stock Fuel (Spool) table and work with that as a guide and see what happens

I will make sure to also log LTFT banks 1 & 2 next time.

[alex@ABRhouston]

No, making it more rich will make the additive value in MS come down from high positives, and multiplicatives will lower the percentage..... positive on either one is the DME adding fuel, negative on either one is the DME removing fuel.


Zero on either value is what you are shooting for (perfect) because that means your main map is on target. the additives and multiplicatives are there technically to adjust for fuel octane differences, elevation, air leaks, restrictions and wear.


sounds like the beginning of WOT area on the map needs more fuel specifically then.


edit: looking at those logs, 20-30% positive needs to be corrected, IMO. The car is adding 20-30% more fuel over the entire fuel map to compensate. On any normal car, this would totally set codes for those being out of range, and would have done so around 12-15%....
But I'm not a tuner- I just know what my MS and % should be on BMW's.

[BuraQ]

No, making it more rich will make the additive value in MS come down from high positives, and multiplicatives will lower the percentage..... positive on either one is the DME adding fuel, negative on either one is the DME removing fuel.


Zero on either value is what you are shooting for (perfect) because that means your main map is on target. the additives and multiplicatives are there technically to adjust for fuel octane differences, elevation, air leaks, restrictions and wear.


sounds like the beginning of WOT area on the map needs more fuel specifically then.


edit: looking at those logs, 20-30% positive needs to be corrected, IMO. The car is adding 20-30% more fuel over the entire fuel map to compensate. On any normal car, this would totally set codes for those being out of range, and would have done so around 12-15%....
But I'm not a tuner- I just know what my MS and % should be on BMW's.

Ok understand now, will see what my adjustments yield

[BuraQ]

Your logs are fairly rich for e50...so not likely there is any real danger there...but your trims are high, I would definitely adjust them. However, you're not logging your long term trims...it'd be nice to see those as well.

Here ya go, this is a new map with increased scalars on both banks equally and LTFT is 0% throughout the entire WOT pull. Had a spin out so the begining of WOT RPMs and load was doing a little dance

http://datazap.me/u/buraq/beastmode-...3-14-15&solo=1

Trims not maxing out anymore on the begining of WOT. I got rid of the Cobb E30 OTS Fuel base, scalars, and fuel spool, reverted back to stock tables and then adjusted them from there.

I just dislike having mismatching scalars but I guess thats why there are indiviual tables for each bank. I get the idea now with the scalars though.

[Steve@Fuel-It!]

From 2.6~4.2 seconds in that log is missing.

I'd also continue to adjust my scalar if it were me...but its looking better.

Given you're getting a PTF protune....I'm sure they'll get it dialed.

[andy_divers]

Have you cleaned your intake valves lately?

[Tzu]

I've been chasing this issue for years.

[BuraQ]

Have you cleaned your intake valves lately?

No not yet, I know they are due, but it seems this "possibility" is ruled out

[135pats]

Dang Bura you aren't playing around with that boost curve

[BuraQ]

Dang Bura you aren't playing around with that boost curve

It was a PITA .....

To everyone, it was a pleasure, and thank you for all the help and info. It served well and hopefully it will help others. The issue has been technically resolved. Might need a little bit more touch up but for now I am leaving it as since I will not be adding anymore power. I need to stay content or else Im gonna get myself in some serious trouble....lol..... http://datazap.me/u/buraq/beastmode-...-17&solo=11-12