Tried Adjusting MAF to stop my car from running so bad

[2002 v6 camaro uncharged]

So, I tried adjusting my MAF to get my LTFTs from running lean. I tought maybe I could tune my problem out but I guess not.

After I loaded my new tune and started the car with my scanner running my LTFTs and STFTs looked really good for about a minute then they both slowly climbed back up to a constant 19.5%.
The idle was somewhat better but the exhaust still had a strong smell of gas.

I am starting to wonder if there is something wrong with my PCM showing the false lean and adding so much unneeded fuel. The car only throws the P0171 & 0174 when I have the MAF plugged. I never throw those codes with the MAF unplugged and all my fuel trims look good. I have been fighting this fuel trim lean crap for 2 months. I have had it to the dealer and they don't know and I have checked and rechecked so many things it is really getting frustrating.

[ February 08, 2006, 09:53 AM: Message edited by: 2002 v6 camaro uncharged ]

[slow6]

you are not calibrating your maf
you need wideband

[2002 v6 camaro uncharged]

Originally posted by slow6:
you are not calibrating your maf
you need wideband

I know I am just trying to see if I can stop my car from running so lean so it stops wasting gas and rocking back and forth at idle.

[2002 v6 camaro uncharged]

I was scanning the car this morning because it ran okay in the cold morning until it went into closed loop (I think this is why). When I first started it the STFTs were 0% and the LTFTs were just slightly negative. As soon as the car warmed up the LTFTs and STFTs slowly went up to 19.5% and as soon as they started going up thats when it started running like crap.

When I am driving and step on the gas the STFTs start moving down to 0% and then when I push on the clutch both STFTs & LTFTs go back up to 19.5%.

[PalmHarborBlkv6]

If everthing else fails, bring it to the Chevy dealer let them hook it up to their computer and they can solve the problem. My dealer in Florida is very reasonable and honest.

[2002 v6 camaro uncharged]

Already tried that, there high performance tech looked at it and could not figure out what is wrong.

[slow6]

dealers can only flash it back to stock

[2002 v6 camaro uncharged]

During lunch I went out and for the MAF I took the HZ values from 1500hz to 4000hz and multiplied them by 2%. Every time I did this the idle got beter. Is the hz values for idle 1500-4000hz?
After I did this then I scanned it and the STFTs were alot closer to 0% but the LTFTs were still 19.5%.
While I was sitting at idle my commanded AFR was around 14.6 but every time I tapped the gas it would go to 15.9 but if I gave it some more gas then it went back down into the 14s. Is the commanded AFR supposed to change when you change the hz values of the MAF. The first time I tried to adjust the MAF hz values I did it way to much and the scanner said the commanded AFR was like 10.6 and it was running like crap. I thought the commanded AFR was supposed to stay the same all the time. Can anyone tell me what that means?

All I do know is the idle is 85% better

[Turbo V6 Camaro]

wait till you can read the WBO2 then use the maff error % pid and that will tell you exacly what you need to do.... also if you runing in open loop th car dont use the O2's for fueling so that probly why the LONG TERM trims are jacked

[2002 v6 camaro uncharged]

The long terms are jacked in closed loop as well. I got it tuned to where the car does not rock me back and forth in my seat. I guess that will have to do until I can find the real problem or just keep running in speed density until I find the problem. I probably won't be able to get a wide band for a few more months until I can save up the extra money.

[2002 v6 camaro uncharged]

That recalibrating of the MAF didn't work. the idle got better when it was warm but the next morning the car would not run so I put it back to stock.

I have not done many scans wiht my MAF plugged in but I did one yesterday and noticed at idle both LTFTs and STFTs were 19.5 and my O2 sensors stayed around 40mV at idle until I started to accelerate then the STFTs moved closer to zero and my LFLTs stayed mainly at 19.5%. Also at idle I think my map semsor was reading 46kPa (I think I will have to check that again). With the MAF unplugged the O2 moved up and down at idle like they should, my LTFTs and STFTs were hovering around zero, and my map read 30 something at idle.

I seafoamed my car through the vacuum to see if smoke came out any where in the engine bay because I hear a tick under load but all the smoke came out of the tail pipes and there was none in the engine bay.

I am running out of options on what it could be the dealer could not figure it out, the pressure test came back fine, everything seems to work fine with the MAF unplugged, I have changed the MAF to see if it was that and there was no change, Vacumm read 19 on the gauge at idle, and the fuel pressure is fine.

[2002 v6 camaro uncharged]

Hey Viper can I email you a couple of scans, one With the MAF unplugged and one with it plugged in and see what you think?

[Turbo V6 Camaro]

Originally posted by 2002 v6 camaro uncharged:
Hey Viper can I email you a couple of scans, one With the MAF unplugged and one with it plugged in and see what you think?

sure can....

[2002 v6 camaro uncharged]

Great, I will email them sometime during my lunch hour.