Running pretty darn good but.....

[TurboJim]

I switched to my 65# injectors and the car runs totally different.

Got my base fuel table pretty close, minimal correction (under 3% pretty much everywhere I have played), now run it in open loop idle at Harry's suggestion, gonna bring the car to work and play with it on the dyno as driving around while looking at a laptop is kinda hazerdous

One thing the car exhibits, which I just cant seem to get rid of is a tip in sag or stumble. When you blip the throttle I get a vvvvahhvrooommmm. In my chip this was caused by insufficient TPS delta and I got rid of it, but there doesnt seem to be anything like this in the FAST box. I've tried AE v TPS, AE v TPS rate of change (this would seem to be delta no?), AE vs MAP, AE vs MAP rate of change, moving the VE boxes around in this operating range only make the car lean or fat, wont remove this stumble.

Is this something to do with the speed density software? I know this is common with MAF cars, but I thought the deal with speed density was they didnt have transport lag (time between MAF reading the extra airflow to the time the ECM richened the mixture) like a MAF car and wouldnt do this.

Its not only my car that does this either, I played with my buddy rich's program and his car did/does the same thing. I guess its something I gotta live with? Its not real bad, or annoying. The car doest backfire or sneeze when snapping the pedal, its just I'd like to get rid of this if it is possible.

Otherwise, idle is silky smooth at 850-900rpm, the fan doesnt make the car hiccup anymore, and putting it in gear feels like stock

Anyone successful getting the car to stop this and have a tip for me?

 

[S2V6RACER]

I have the same problem. It's a joke. I have tried everything myself and have learned to deal with it.

I don't drive mine on the street though.

Ted


I'll be watching this thread.

 

[TurboTR]

It's just AE vs delta TPS. Easy enough to fix. The VE cells that it moves through on a throtle blip also have to be right of course. Otherwise the AE shot winds up covering up for that too.

TurboTR

 

[TurboJim]

I'll try again, but it seemed nothing helped, adding or removing fuel. By my old O2 sensor, no matter which way I went, it was always a lean sag/stumble. (Looking at old AF gauge....not very accurate maybe, but I know how it reacts, and is how I set up my chips)

 

[stevec]

Tip In Stumble

Jim, I have had similar problem in cars I have set up. Does the tip in get worse depending upon ho w hard you blip the throttle??

You said your idleing in open loop now. What rpm does your closed loop correction come on?? Maybe it is trying to correct the a/f because it momentarilly goes into closed loop.

Was the problem wosre with the smaller injectors. What is your idle AF ratio. With the larger injectors I believe this problem is less apparent. I have 160 # the car AF @ idle is 11.5 if you try and lean it out then drop in gear I gets way too lean.

Steve C

 

[TurboJim]

Re: Tip In Stumble

Originally posted by stevec
Jim, I have had similar problem in cars I have set up. Does the tip in get worse depending upon ho w hard you blip the throttle??

Seems to be worse in slight throttle movement. If I move it a couple degrees its worse than if I roll in and then stab it.

You said your idleing in open loop now. What rpm does your closed loop correction come on?? Maybe it is trying to correct the a/f because it momentarilly goes into closed loop.

Closed loop in at 1500, out at 1100. Target has been 14.1 down to 12.6 and it does it anywhere inbetween.

Was the problem wosre with the smaller injectors. What is your idle AF ratio. With the larger injectors I believe this problem is less apparent. I have 160 # the car AF @ idle is 11.5 if you try and lean it out then drop in gear I gets way too lean.

Problem is about the same. My pal Rich's car does it too. I went from 50's to 65's and he has 72's.

Steve C

Heya man, been awhile! Hows tricks! I told yer bro to say hi awhile back, hope all is well. Maybe see ya at etown one of these days.

 

[Butch]

I have a DFI B2B setup and it does this too. I have my base map set pretty close I think (not wideband) but when I adjust AE v TPS, AE v TPS rate of change, it screws up my whole fuel map.

I know there is a way to cure this, but I can't figure it out. There is no way someone that is serious about racing would live with this problem. Can you imagine the 60' times? It's hard enough to try and control the rpm's and boost level at the line without having to worry about this problem too.

Maybe Craig will come on here and help us out.

Butch

 

[TurboTR]

>AE v TPS rate of change, it screws up my whole fuel map.

I don't know why it would do that. The 2 are independent.

TurboJim how about sending me your .gct and a data log from warmed up idle, blipping the throttle once to make it stumble. The datalog needs to show a/f ratio, and be set up properly where it will overlay onto the VE table. I'll see if I can fix it. turbotking@hotmail.com.

TurboTR

 

[Butch]

I don't mean that is changes my base fuel map. The values in the cells don't change. What I mean is that it seems to change the fuel delivery to a point that it makes it worse not better.

Maybe I need to reduce the base map some to allow for enrichment, hell I don't know. All I know is I havent been able to figure it out

Butch

 

[tazgn]

I may be all screwed up here, but I seem to remember that there is another graph (setting) that goes along with all the AE enrichment settings. I read it in the windows version help stuff. I was able to tune out the stumble on my car by playing with the AE vs TPS rate and the AE vs TPS Postion and some other graph. Maybe it was the postion and rate go hand in hand. Damn I don't remember right now. But after some reading, I was actually able to get rid of the stumble.

Derrick

 

[TurboTR]

Butch try logging the stumble. Usually you'll see a lean spike on a quick tip in, severe enough to literally stall the engine for a few cycles. If you would try logging your stumble and report back; I'm pretty sure we can solve it

TurboTR

 

[Craig Smith]

Take a look in the demo.gct file and note the shape and positioning of the AE fuel vs. TPS Position graph. Also, read the help files built into C-Com WP for more info on how this table and the other AE fuel tables work. With the VE table calibrated properly, I really bet you can work this out rather easily.

Keep in mind that with 160 lb/hr injectors, it will take next to nothing in terms of injector pulsewidth from the AE vs. TPS rate of change and MAP rate of change graphs to get the motor to rev quickly. It's real easy to add too much fuel and have poor results.

 

[S2V6RACER]

Originally posted by Butch
I have a DFI B2B setup and it does this too. I have my base map set pretty close I think (not wideband) but when I adjust AE v TPS, AE v TPS rate of change, it screws up my whole fuel map.

I know there is a way to cure this, but I can't figure it out. There is no way someone that is serious about racing would live with this problem. Can you imagine the 60' times? It's hard enough to try and control the rpm's and boost level at the line without having to worry about this problem too.

Maybe Craig will come on here and help us out.

Butch

This problem on mine doesn't affect the car at launch. It is more of a problem when I am driving it on the trailer and backing up out of the pits. It will not stall the car. I am going to datalog the problem, I don't know why I didn't think of that.

 

[norbs]

The tip in hesitation, is impossible to remove from what i have tinkered with so far. It actually spikes to 15.94 off idle throttle changes. I have adjusted the ae tables and the 15.94 is still there? What am i doing wrong?

 

[Jerryl]

Since some of the greatest Buick minds have posted in this thread (no pun intended), I thought I would ask. I know I am 9 years behind the curve but here it goes;
Looking at some logs, I see a lean spike but only sometimes, not all the time (Weird). FP is good.

Just wondering how did you gentlemen fixed the temporary lean spike (Stock ECM TT 6.0) on light accelerator pedal change?

 

[HighPSI]

AE Fuel Tables

 

[northerngn]

AE Fuel Tables

TOTALLY!:smile: