Folks,
I've been struggling with this for a few days. When I go WOT, I get an initial lean spike and then when the 2-3 shift occurs. Any ideas? Fuel pressure never gets below 58psi running on 50lb injectors on an LS2 - A4 tranny.
TIA,
Mark
Folks,
I've been struggling with this for a few days. When I go WOT, I get an initial lean spike and then when the 2-3 shift occurs. Any ideas? Fuel pressure never gets below 58psi running on 50lb injectors on an LS2 - A4 tranny.
TIA,
Mark
Last edited by barkingspud; 10-22-2006 at 10:10 AM.
I would suspect that there is a bump in MAP just
a bit before that point, putting the car momentarily
into speed density mode and perhaps SD tuning
wants some attention?
Also possible that there is something like the
timing pullback from torque management, making
a poor combustion and blowing unused air out the
pipe. Or on a drive by wire car, maybe some silly
throttle closing action dropping you out of PE
momentarily.
First see whether anything happens to the commanded
AFR (EQ ratio) that would account for it (like PE
mode disable). If it's not "intentional" then you have
to root out the bad actor.
Originally Posted by jimmyblue
Thanks Jimmy,
I suspect it's Torque Management since it seems to bog between the 2-3 shift at WOT. OK...I just looked at my tune again. I can't see anything in TM that would cause this. Maybe someone would be kind enough to have a look and comment. I'm attaching my tune and the logfile that I used to generate the graph. Thanks in advance.
Mark
Attachment 2204
Attachment 2205
Last edited by barkingspud; 10-22-2006 at 10:05 AM.
Auto? If so have you upped the shift pressures for the 2-3 shift?
Haven't touched shift pressure other than the Force Motor Cal....
Looking at your scan log, the wideband is very erratic, any way of smoothing it? It is not torque management as it is zeroed out in the editor, and the spark timing isn't retarding on the upshifts. But your really need to increase your shift pressures as I see alot of slip during the upshifts (1-2) is the worst.
Russ kemp
Russ,
How do you read the slippage on the shifts? I'm a newbie here.....And, THANKS!! Not sure how I'd smooth the WB. I have an AEM WB and it seems that it samples in 1/10sec increments......
Mark
Look at the rpm drop on the 1-2 shift, yours has a gradual drop. The rpm should have a sharp drop (about a 45* angle) when up shifting. I use the FJO Racing wideband, and it is rock steady. Contact AEM and see if there is a way to change the sampling rate.
Russ Kemp
Ahhh...OK. So, should I just up the Max Pressure value or mess with the 1-2 shift properties?
Try this these shift pressures. I can make them firmer or softer.
Russ Kemp
Thanks Russ!!
Last edited by barkingspud; 10-22-2006 at 04:14 PM.
Just tried out the shift tables. Very nice, Thanks again Russ. That lean spike is still there for sure though. It occurs only during the 1-2 and 2-3 shift and for about 1/2sec or the duration of the shift. I have no clue....Anyone care to take a stab at this one? Oh, and I put the car in SD to eliminate the MAF.....I've attached my latest logfile.....
TIA,
Mark
Attachment 2217
Last edited by barkingspud; 10-22-2006 at 07:36 PM.
Did you do a write entire after applying the maf patch? If not the fuel will be shut off above 11500 HZ. I would do a Maf tune on your car, no gain by trying to tune the VE if you have a functioning Maf.
Russ Kemp
Yes, I patched the MAF awhile ago and did a write entire. I only put it into SD to see fi there was any difference....
Well, I re-patched the MAF just to make sure something didn't happen over the course of the cam install and tune. Went out and logged some data with the same result. Logfile attached. Any guesses. Only thing I can come up with is the ground for my AEM WB. I saw on another thread that it might be best to ground it to the MPVI box. Any takers??
TIA,
Mark
Attachment 2236
Looking at this log, buth spikes appear to be where you are
at an RPM flat-top and I suspect you are on the rev limiter
and seeing its fuel-cut action.
How about backing out the shiftpoints and making sure you're
off fuel cut, and see if the spikes go away?
My ground for my FJO wideband is hooked up at the MVPI box.
Russ Kemp
That's what I was thinking. I'll check it out and see.
Thanks Russ. That's the other suggestion AEM had is to ground it as close to the box as possible. I'm going to check my shift points as Jimmyblue suggests first and mess with the ground point afterwards.
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