Lean on Tip in

Brian-Mc · 09-09-2005, 11:52 PM

Ok.. I have been following the Accel global multi thread... I have noticed that my car is having a lean condition when I accel from a coasting condition or very light throttle (load). It is causing it to stumble slightly and about to drive me crazy... I can give it alittle more throttle and able to overcome the lean issue but want to get the stumble gone. I have raised my Accel global multi to 1 but still have the issue. I have noticed that the commanded is showing about 13 or so A/F and my WB is showing about 16 - 18 a/f. I have made an adjustment to the MAF using the EA which did add alittle fuel at the area that the MAF was at when this happened. I will verify this tomorrow to determine if it will work. Am I on the right track or am I heading down a wrong path?

I have not played with my MAF curve in several months... so this could be the problem. your thoughts?

gt90stang · 09-10-2005, 12:13 AM

What processor you running?

Brian-Mc · 09-10-2005, 07:25 AM

I am using the A9L processor.

Dale McPeters · 09-10-2005, 09:28 AM

Brian-Mc,

It could be a number of things. One is the MAF as you have stated in your original post, another could be the Fuel Table - Air Meters Backflow correction (as it is load based if I remember correctly). The backflow correction table will make a difference depending on where in the intake tract you have the maf meter installed. Also wether it is a draw thru or blow thru application. What load the engine is at when all this happens etc. etc. I had a problem with this in blow-thru when testing some things on my car, as the TB was snaping shut and causing a lot of backwash or intake reversion (even with blow off valve) thru the maf meter......

Another area to look at would possibly be the Accel Pump Table as discussed in the other thread....

Run a datalog to see what load is when this happens as turbo setups will have a higher load at lower engine rpm/part throttle conditions as you well know.

On mine I changed the backflow correction table from about .3-.4 load/1500rpm to 1.98 which seemed to help in my case. Still in the testing phases.....

Yours may differ depending on boost, intake tract, maf location etc.

exgmguy · 09-10-2005, 06:37 PM

I had the same problem, and fattening up the MAF curve down low did the trick.

Brian-Mc · 09-11-2005, 12:05 PM

Well I think I may be on the right track... I took the updated MAF curve and things improved alot. I also reviewed a tune Clint sent me to check out and noticed his lugging sealevel and altitude OL fuel multiplier (function) was set to .5 while mine was still at 1 which was the same from the stock A9L profile. I did go on and adjust those as well... the acceleration when in the higher gears seemed to be a little better. I have yet to inquire what these two settings do other than some type of fuel multiplier.

09-09-2005, 11:52 PM	#1
Brian-Mc Member Join Date: Aug 2005 Location: Georgetown Ky Posts: 48	Lean on Tip in Ok.. I have been following the Accel global multi thread... I have noticed that my car is having a lean condition when I accel from a coasting condition or very light throttle (load). It is causing it to stumble slightly and about to drive me crazy... I can give it alittle more throttle and able to overcome the lean issue but want to get the stumble gone. I have raised my Accel global multi to 1 but still have the issue. I have noticed that the commanded is showing about 13 or so A/F and my WB is showing about 16 - 18 a/f. I have made an adjustment to the MAF using the EA which did add alittle fuel at the area that the MAF was at when this happened. I will verify this tomorrow to determine if it will work. Am I on the right track or am I heading down a wrong path? I have not played with my MAF curve in several months... so this could be the problem. your thoughts? __________________ 306 (stock block),TFS Track Heat Heads, E303 Cam, TFS track heat intake, 70 mm TB, 75mm Pro-M,42 lb injectors,Aeromotive AFPR, 255 lph intank, Crane Hi-6/LX-92. Turbonetics 60-1 hi-fi Best ET: 11.88 @ 117mph 427 HP/ 480 ftlb TQ

09-10-2005, 12:13 AM	#2
gt90stang Member Join Date: Aug 2005 Posts: 72	Re: Lean on Tip in What processor you running?

09-10-2005, 07:25 AM	#3
Brian-Mc Member Join Date: Aug 2005 Location: Georgetown Ky Posts: 48	Re: Lean on Tip in I am using the A9L processor. __________________ 306 (stock block),TFS Track Heat Heads, E303 Cam, TFS track heat intake, 70 mm TB, 75mm Pro-M,42 lb injectors,Aeromotive AFPR, 255 lph intank, Crane Hi-6/LX-92. Turbonetics 60-1 hi-fi Best ET: 11.88 @ 117mph 427 HP/ 480 ftlb TQ

09-10-2005, 09:28 AM	#4
Dale McPeters 5.0 Block/Walnut Cracker Join Date: May 2005 Location: Working.... Posts: 2,409	Re: Lean on Tip in Brian-Mc, It could be a number of things. One is the MAF as you have stated in your original post, another could be the Fuel Table - Air Meters Backflow correction (as it is load based if I remember correctly). The backflow correction table will make a difference depending on where in the intake tract you have the maf meter installed. Also wether it is a draw thru or blow thru application. What load the engine is at when all this happens etc. etc. I had a problem with this in blow-thru when testing some things on my car, as the TB was snaping shut and causing a lot of backwash or intake reversion (even with blow off valve) thru the maf meter...... Another area to look at would possibly be the Accel Pump Table as discussed in the other thread.... Run a datalog to see what load is when this happens as turbo setups will have a higher load at lower engine rpm/part throttle conditions as you well know. On mine I changed the backflow correction table from about .3-.4 load/1500rpm to 1.98 which seemed to help in my case. Still in the testing phases..... Yours may differ depending on boost, intake tract, maf location etc.

09-10-2005, 06:37 PM	#5
exgmguy Junior Member Join Date: Aug 2005 Posts: 6	Re: Lean on Tip in I had the same problem, and fattening up the MAF curve down low did the trick.

09-11-2005, 12:05 PM	#6
Brian-Mc Member Join Date: Aug 2005 Location: Georgetown Ky Posts: 48	Re: Lean on Tip in Well I think I may be on the right track... I took the updated MAF curve and things improved alot. I also reviewed a tune Clint sent me to check out and noticed his lugging sealevel and altitude OL fuel multiplier (function) was set to .5 while mine was still at 1 which was the same from the stock A9L profile. I did go on and adjust those as well... the acceleration when in the higher gears seemed to be a little better. I have yet to inquire what these two settings do other than some type of fuel multiplier. __________________ 306 (stock block),TFS Track Heat Heads, E303 Cam, TFS track heat intake, 70 mm TB, 75mm Pro-M,42 lb injectors,Aeromotive AFPR, 255 lph intank, Crane Hi-6/LX-92. Turbonetics 60-1 hi-fi Best ET: 11.88 @ 117mph 427 HP/ 480 ftlb TQ