Help! weird LTFT, High MAF

[awillis98]

Ok, me and a guy i know have been working on retuning my car. the problem is he say's my MAF should be around 2500 at idle and it's more like 3500. so it's running super rich. what would cause the Maf to read so high. i have already checked all hose's i have also went around the hole motor with carb cleaner and nothing. i think the MAF reading high has made My LFTF real wakey. we have devided the MAF table by .9 twice to lean it out a bit. it was so rich i wouldn't go into close loop. i'm going to post my most recent scan of the car. any help at this point is good help.

[5_Liter_Eater]

Whatever Hz you idle at is irrelevant. Could be due to your cam, headers, intake, etc. Don't worry about it, just get the trims in line like you have been. The trims in the files you sent me look better than this so you're on the right track. What do you mean so rich it would not go closed loop?

[awillis98]

It was so pig rich here is what it was doing. this scan is pretty bad (2). this is the scan i did on the way to scan from the last scan i sent you.

[awillis98]

and this on was with the % past. so let me know if you think it's close enough to start doing it by half %.

[johnh]

As pointed out the MAF Hz doesn't matter that much. Have you turned up your idle rpm (for the XP Cam)? I have mine at 850 and my idle MAF is ~3100 Hz. Don't worry about that...just get the trims in line with a MAF tune.

Don't make global changes to the entire MAF table--change only the parts you are tuning based on trims.

Dividing by .9 actually makes it richer...eg 15 g/s / .9 = 16.6 so now the PCM sees MORE air and will then add MORE fuel. 16.6 / .9 = 18.4 --> 22% richer!! (if my math is right.. 3.4/15 )

[Perforator]

John is right. I think you wanted to multiply by .9 to lean it out, not divide.

[awillis98]

did you guys get a chance to look at my scan. other then the little KR up top it's not to bad. that has to be fuel related. i had it dyno tuned and had 0* in 100F day making 280HP. and since fixed a exhaust leak that made my car run rich. so i have to tune accurdingly.

[louvered97gtp]

Curious, what pulley were your running on your Dyno run?

[awillis98]

for the dyno run it was a 3.25 pulley. that's what is on it now. i've got newer scans that are almost perfect. now i need a Wideband and Get some new stuff. want to get a Gen V, N*, New MAF. i can post a scan later

[JerryH]

Silly quesiton time... you have a tuner, but you are letting someone (that is showing some signs of not being a very good tuner), tune your car for you?

Anyone that told me my idle HZ had to be "X"... I'd immediately not feel comfortable doing anything more than scanning my car. This person really doesn't have a lot of experience with tuning.

That idle richness that you refer to is due to the XP cam's overlap. This is normal and you can tune this out with a few basic MAF tunes. The HZ is not all that important, its the learned trims that will be quite negative (rich) that indicates fueling status.

Your runs from home...WAY LEAN. 850's and 5+ degrees of Kr. Stay out of the throttle until you fix this. At least your LTFT and STFT are locking in properly, thats a step in the right direction.

Suggestion time: Set your dashboard so that the KR window is larger and set an alert level of 3. When it turns red, out of the corner of your eye you see red and back off immediately. No use beating on it past that. It shows an issue that needs to be resolved before moving further.

[awillis98]

here we go it's been some time since my last post i've been doing lots of reading and been working on some tuning basics. here is my most recent scans and vcm file.

[MMGT1]

Looks pretty good. I'd look into bigger injectors soon though! Don't really want to go above 80% on the duty cycle.

[Russ K]

I've seen over 100% IDC on stock GTP's. I wouldn't even consider larger injectors until the IDC was 100%.

And without a wideband, the AFR may be too rich increasing the IDC.

Russ Kemp