Weird Low Fuel Trim

[Kevbo6204]

Okay I just got my SAFC II installed yesterday and this morning I took it out to start tuning it. I read the guide on here to tune with SAFC so I had some guidelines to follow. Well When I went out my trims were as follows. Low=179 Mid=165 High=165 according to my logger. This was after I let the car come up to temp and drove it down the road maybe 5 miles. I then parked the car for about 5 minutes and turned up the low throttle setting @ the 1000rpm point +20 to smooth out the ehaust at idle. I then did another 1 through third gear pull. When i got back home (5 miles away) I looked at my low trim. I almost crapped myself it is now reading 237. I have driven it since for another 5 miles and it wont go away. Even letting it idle it doesnt work. I have read other posts on this but have not found anyone that has had low fuel trims this high. I never saw more than 3 counts of knock if that helps. Tell me what u guys think.

Thanks
Kev

 

[steve]

Those numbers are impossible. What logger are you using?

Steve

 

[Kevbo6204]

The good old palmnstein on a palm. The logger is flawless and I got it off of ebay. Very nice actually. It has a molded cable and everything. The value I am seeing says 237. Are all of them impossible or am I just reading something wrong?

Thanks,
Kev

 

[Kevbo6204]

Okay update here steve. I just switched and tried using MMcD and awesome. Much better looking numbers! For Mid and high I have 100% dead nuts. However the Low is high at 139. I turned up the the Low throttle at the 1000rpm point a bit to see if it moves down a bit.

 

[steve]

Palm 'nStein is garbage if for no other reason than it doesn't use the same values that TMO and everything else uses. Lets not talk about all the crashes.

Which version of MMCd did you get?

Steve

 

[Kevbo6204]

Its version 1.8g. I am haveing the same issues as others. I let the car warm up for 15 min or more and I have no changes in the low trim. Stuck at 139%. My o2 sensor doesnt cycle either Im getting a constant .07v @ idle for O2R and 3.49v @ idle for O2F. Possibly a bad o2 sensor?

Thanks,
Kev

 

[steve]

Make sure to click on the title bar and select options, preferences, car = DSM and set units to english.

The only O2 sensor on a 1G DSM is O2-R, ignore the other in MMCd and replace your dead O2 sensor. It should start out low and start climbing as the exhause heats up. After the ECT >86F and the timout expires the O2-R and FTO2 will begin to cycle as the ECU enters closed loop. Once the ECT >186F the ECU will begin to update the other fuel trims depending on the MAF HZ at the time.

If you still running the stock MAF and injectors your SAFC correction settings should be 0.

Steve

 

[Kevbo6204]

Thanks for the help Steve! I will be getting an O2 sensor very soon. ill keep you up to date.

Thanks Again,
Kev

 

[Kevbo6204]

k i got some interesting things happening now....I can get the mid and high to sit right around 106% but the low trim stays at a constant 139. Damn thing doesnt drop. I can iff i keep turning up the SAFC really high. High meaning plus 50 then it goes down and setlles at 118. Any suggestions? I have already reset the ECU and whatnot. It still goes right back up and all. Thats with everything zeroed out too. Any suggestions?


THanks,
Kev

 

[ICGerms]

Is this happening with the new O2 sensor?

 

[Kevbo6204]

Alrighty its not happening anymore...I now have low fuel trim of 110% I started messing around with it more last night and honestly I cant believe how nice the car feels after I have roughly tuned it. I turned the boost down to stock settings and started tuning and the car feels like it was @ 15lbs when its only @ 8lbs. Does anyone have anymore comments, tricks, or things to look for?


Thanks,
Kev