Thread: VE Tuning

OK everyone im sure this has been descused a million times. but im trying to run my 2000 Grand prix GTP WITHOUT the MAF sensor, before you say it cant be done, dont, read on, so ive been trying to figure out y the car gos rich well in decel car must be over 20mph and off throttle and AFR is about 10-11 pig rich Y, this is the only problem with the car runing no MAF.. well from scanning i can see only one thing that would cause this with the MAF pluged in IAC counts stay around 70-80 counts well doing 30 plus MPH and off throttle decel I also have DFCO turned off so theres no interference. Now when i Unplug The MAF sensor with the same sonario my IAC counts are down around 40-50 witch makes perfect sense y the car is so rich with no maf, Now ive been trying tables apon tables and cant get the counts to come up i use DHP power tuner and tiny tuner and also have hptuners anyone have any luck finding a table to bring the IAC counts up With the MAF unpluged and speed above 20MPH and no throttle aplied looking for help as i no theres guys here that have been wanting and trying to figure this out i no its possible the LS1 will run MAF less so will the GTP we just must figure out how to bring the IAC counts UP well costing above 20MPH Lets figure this Out HOPE everyone will give Good Info not just say it cant be Done it can it just needs to be figured out. Thanks to anyone who Has info on this.

no its how the 3800 works same as always 3.4inch pully headers no cat high flow mufflers hot air intake K and N lol and my Tune With Take your pick HP Tuners or DHP/Tiny Tuner but cant find a table in the bin to control IAC the way i want doesnt really hurt anything as the car is resiving the same amount of fuel just not the same amount of air off throttle because of the IAC counts this is the delema everyone is having when trying to do a VE tune on there 2000 Grand Prix GTP if you dont belive my info go scan your gtp with the MAF unpluged and pluged in and watch what your IAC counts do when off throttle above 20MPH. Have owned and been tuning with this setup since 160,000km car has 249,429km and runs the same.

Originally Posted by Scottydoggs

just how rich is it going on decel? i tune with dhp and dont have this issue at all, it might hit a -7 or 8, but thats it, runs -5 idle -3 or lower cruising and -1.3 wot with a a/f ratio of 11.3 ish wot from a wideband.

OK well Cruzing with throttle 1% or more AFR is 14.5 Like it is suppose to be, But well OFF the Throttle 0% and above 20MPH coasting or rolling AFR is 10 to 11AFR PIG RICH as soon as speed drops below 20MPH AFR comes back to 14.5. car doesnt go into DFCO because ive turned it off with TINY TUNER. MAF IS NO LONGER ALIVE car runs full OPEN LOOP TUNE when the MAF was alive the tune was spot on with a stock maf table VE tuning has always worked this way when unpluging MAF even when the car was In CLOSED LOOP Tune Have Tryed Many tables in tiny tuner DHP HP tuners to correct this issue sure im just missing something stupid.

Originally Posted by Scottydoggs

just how rich is it going on decel? i tune with dhp and dont have this issue at all, it might hit a -7 or 8, but thats it, runs -5 idle -3 or lower cruising and -1.3 wot with a a/f ratio of 11.3 ish wot from a wideband.

AND IS YOUR MAF PLUGED IN OR UNPLUGED Mine is unpluged running off VE TABLE

Originally Posted by GTPpower

What happens if you turn deceleration eleanment back on? Can you lean it out?

I'm also curious why you don't just run a maf? Lsx cars have way more resolution than us, since they actually use it for fuel calculations.

If I turn dfco back on the car dies more when coming to a stop. Like the maf setup just sick of buying new sensors at $200 a pop. I'm going to try switch the maf fail mode to 3 and turn transiate fuel calc mode to 2 and see if I can get a good tune that way? Any thoughts on this would be great

Originally Posted by GTPpower

What happens if you turn deceleration eleanment back on? Can you lean it out?

I'm also curious why you don't just run a maf? Lsx cars have way more resolution than us, since they actually use it for fuel calculations.

Deceleration eleanment is on I have DFCO turned off its the iac velve that causes the rich condition a scan proves it.

Originally Posted by Turbocharged400sbc

OUR VE TABLES HAVE CRAPPY RESOLUTION, especially over 100kpa

VE stuff is the failsafe/limp backup of the MAF failure, the MAF/rpm = load being a better measurement of fueling than map/rpm=load

VE/SD works quite well with the known VE of the engine, its just not that good at low flow conditions where the MAF sensor gives direct mass measurements of the air, and thus direct accurate fuel can be sprayed.

I tune VE with no PE enabled and get it drivable for when/if the maf fails, MAF/FTC tuning is quite a bit better for drivability

Yes figured it out running on just ve table without the maf properly know. Know just to figure out how to get accelerate enrichment back on to get control of the knock

In other words I got rid of my rich condition

This is what I did to fix my problem in a 2000 Grand Prix 3.8 s/c l67 fixes big LTFT with maf fail.

Unplug MAF or set hz fail high from 11500hz to 0

Dhp and tiny tuner ONLY supercharger tables

Boost decel tps table 1.7tps Chang to 0 just like the l36

Boost decel MPH is 20MPH set to 250MPH

These peramatures are not in hptuners I would think they would add them as they get rid of the really rich condition when maf fails. The boost solenoid when maf is failed will go to 0% when above 20mph and less then 1.7%tps in revers the solenoid will still go to 0% but you can now drive the car with the maf failed as it won't do the bucking bronco as trims go from -15 off throttle to 0 or + trims once under 20mph caussing the car to buck if you have an L67 and stock tune unplug maf and see what I mean.

This is something that I can't find on the net anywhere and makes a big difference hope this helps everyone when reading the tuning guides and trying to VE tune your l67 properly. The only thing that helped me to properly tune my VE table

Also in tiny tuner make sure you maf failure airmass calc is set to use ve 2 not gm airmass fail mode 3 as it is very unstable

Originally Posted by notdarkhorizon

air mass fail mode 3 is "alpha N" mode, which does not use a MAP sensor, TPS only. Its the common failure mode of most 3800 cars, not SD like some think.

Are we better to run alpha N over SD ve table I just found it was all over might not have played enough though what's your opinion