When car is in open loop and fuel trims are reset to 0 Commanded AFR=WB which is good , but as soon as I exit open loop , fuel trims droping to -15% and leans to ~16.2 (slow6) and -5% on my car. As soon as I hit closed loop off and reset FT its perfect again.
Is that PCM reads o2 sensors wrong or its WB shows incorrect readings?(I had mine just recently recalibrated) or it needs some extra tweaking in different area then maf??(injectors?)
Please help us here.
www.turbofirebird.com tuned with HPT MPVI Pro, LC-1.
if youre talking about that one last scan that I did, which you told me to hit "reset ft trims" during the middle of a NO VCM controls scan, with PE=14.7=ON
I ONLY hit "reset ft trims" in the middle of the scan.
thanks alot!
help US out RUSS!! we been doin our own thing
Post your tunes guys, and I'll take a look at them to see what your doing. Do you have the pe table at 0 % tps & the base afr set to 14.7 while tuning < 7500 hz? And make sure that you reset the LTFT BEFORE scanning.
Russ Kemp
yes , we have all that that done. I understand every part and step in maf tuning process.
thats slow6 scan , as you see ~1100 he locked FT at 0 and his AFR went from lean to normal.
www.turbofirebird.com tuned with HPT MPVI Pro, LC-1.
In closed loop, the AFR should be ~14.2-15.2. Your fuel trims can go +- 25% IF nec to maintain the closed loop AFR. I would verify that your wideband is accurate. And the maf afr error % is being averaged while the car is in closed loop as well. That is why your must either unplug the O2 sens 1 or disable closed loop with the editor. The scan log is already started before you turned off closed loop and reset the fuel trims using the vcm controls, making the maf afr error % histogram inaccurate.
Russ Kemp
Yes, mine seems to be alot wider spectrum than that!Originally Posted by Russ K
yes, when the engne is off, but im scanning in HPT, I will turn on my wideband sensor and HPT will show 14.7 for a second (then change vigorously). The gauge will show like 14.8 for awhile.why would it not be averaging?
yes, weve been doing open loop sometimes.
Maybe thats our problem here? We need to stick to Open Loop?
thats exactly what i was thinking too
thanks alot guys!
filez...
help plz, I'm getting bad MPG
You need to make sure the that the commanded AFR is at 14.7 BEFORE you start scanning. If not, just hit the space bar to stop & restart the scanner. Scanning the car when the commanded AFR is as lean as 15.6, then hitting DFCO and then having a 16.4 commanded AFR is impossible to tune, as the average AFR is based on the wrong commanded AFR.
You can set the Deceleration Enleanment > Enable TPS Delta to 100 % or set the DE Modifier > Vacuum table to 0. This should disable DFCO. I decel smoothly while scanning so I don't disable the DFCO.
Do you have any exhaust leaks upstream of your wideband?
Russ Kemp
not that I know of. Everyone asks me this a million times. But other than feeling by hand, I have no way of knowing... I fixed all the leaks I thought.. and moved my wb more upstream.
I COULD stick it in B1S1, but the car will run like ass (according to viper)
If you can hear an exhaust leak, I would pin point the leak using a stethoscope (steal one from your doctor) with the engine running.
If I was tuning your car, I would install the wideband in place of the B1S1.
Russ Kemp
every time you let off the gas it must go lean, how do you think gas is getting into exhaust if you injectors are closed?
www.turbofirebird.com tuned with HPT MPVI Pro, LC-1.
anyways
I wait for 14.7 commanded
then re-start the scanner to clear the useless data...
hit "reset fuel trims"
then hit "closed loop off"
then hit "reset fuel trims"
the scan is legit, maybe not the WB, but I'm not useing the WB
Histogram #1 is wb-less maf recalibrator (maf error %)
Last edited by slow6; 11-26-2006 at 12:46 PM.
Reply With Quote