PocketLogger Log Question

[le0net]

Hi!

Sorry for a long post, i have a rebuild 1990 Tsi AWD with 50trim turbo, 3" MAFT+ translator, rewired 250 pump, AFP regulator (40 on idle, almost 50 when reving) 660cc injectors, SAFC, no adjustements done since logger shows between 90-115% on all fuel trims. Stock intake, FMIC, EVO3 exhaust, EVO2 O2 housing, New 02 sensor, 2,5" to 3" downpipe, no CAT, 3" all the way. Boost about 13PSI

Just confused about knock level at high rpm, and o2 sensor changing that much on lower RPM.

Could someone have a tips on what to log more, or should i add fuel att higher rev or what, boostleak?

A few rows from logging below...

Top knock was 41 at one point and high rpm.

RPM Knock O2
2719.0 0.0 0.24
2781.0 0.0 0.43
2781.0 0.0 0.67
2813.0 0.0 0.82
2844.0 0.0 0.8
2844.0 0.0 0.63
2844.0 0.0 0.45
2906.0 0.0 0.37
2938.0 0.0 0.37
2938.0 0.0 0.59
2938.0 0.0 0.78
3063.0 0.0 0.8
3094.0 0.0 0.75
3063.0 0.0 0.53
3125.0 0.0 0.29
3188.0 0.0 0.22
3156.0 0.0 0.69
3094.0 0.0 0.92
3031.0 0.0 0.94
1656.0 0.0 0.12
1750.0 0.0 0.1
1906.0 0.0 0.1
1844.0 0.0 0.1
1813.0 0.0 0.16
1906.0 0.0 0.29
1906.0 0.0 0.39
1938.0 0.0 0.55
2000.0 0.0 0.69
4031.0 0.0 0.82
4063.0 0.0 0.86
4031.0 0.0 0.9
4063.0 0.0 0.9
4344.0 1.0 0.9
4313.0 1.0 0.9
4469.0 8.0 0.9
4500.0 12.0 0.9
4719.0 12.0 0.9
5594.0 15.0 0.94
5781.0 15.0 0.92
5688.0 15.0 0.94
5938.0 15.0 0.92
5969.0 22.0 0.94

 

[turboAWDfanatic]

Could the reason be that i have a 3" GM MAF in blowtrough mode and a MAF-T instead of the stock MAF?

Could be. I konw NOTHING about tuning with MAF-T, but it makes sense that if that is set up improperly it could be making it necessary to offset so far with the AFC. Look into setting that up and then make your adjustments from there to aim for good A/F mixture and proper timing. Also, get a wideband O2 setup like Zeitronix or AEM Uego. They are a great tool for tuning accurately.

 

[kenamond]

No. Kenamond posted some great info, but I think he thought you were pulling air (/fuel) out with your AFC. The way I understand it, as you go negative, the ECU thinks there's less air, and you end up with more aggressive timing (more advance). If you add air (/fuel), the ECU thinks there's more airflow and you get less aggressive timing.

True. I didn't realize/notice that he had GM MAF, and I thought he was pulling air, not adding it. I also know very little about GM MAF and MAF-T. I could search and learn and explain, but so could he .

I'd do a pull logging airflow and visually monitoring boost during the pull (still log the other stuff, too). Post the log and your boost observation (hit 14psi at 3400 and crept to 20 at 5k and held at 20 til redline...don't have to be super exact). That'd fill in one piece of this puzzle. Am I recalling correctly that the 1g loggers report airflow differently than 2g? Or maybe 1g loggers can directly log the Hz signal fed to the ECU? I forget. Anyway, that additional log info might give us some new ideas.

 

[le0net]

Havent seen a setup like mine, thats why i have all my Q

The MAF-T is set up for a 3" MAF and 660CC injectors, everything else is zeroed out, just the base setting for compensating for the bigger MAF and Injectors, all other tuning is done from the SAFC.

I will do a pull with 3rd from 2500rpm, log it and have more info.

See you soon

Leif

 

[kenamond]

The fuel trims are different between 1g and 2g. Here's a quote from the Definitive Piggyback Tuning Guide

I just reread that guide (been a long time, and I've learned a bunch since then). I've been told and have personally seen evidence that the 2g has 2 LTFT: Lo and Mid. And I've also been told but can't verify that the 1g has 2 LTFT: Lo and Hi. Both have STFT. I can't argue about the 1g, but I've watched my 2g's LTFT switch from Lo to Mid while staring at the logger (I hear most loggers will just show one LTFT variable, but it is displaying one of the two trims). I could watch the idle LTFT value, then as I slowly increase revs (in neutral), it switches to a different value. Then I drop the rpm and it goes back to the first value.

Wish I could remember which thread it was where we were discussing the 1g vs 2g trims.

Someone with DSMlink and access to their forum would certainly be able to answer this for certain, as the link folks *know*.

 

[le0net]

Seems the internal wastegate on the 50-trim is too small to be able to remove boost if tuned too low, so i moved the boost source closer to the WG and raised boost to 18psi, now its steady, no creep.

Continuing thread in another topic, got a different problem now.

fuel-cut-50-trim-660cc-3-gm-maf-t-255-walbrol