Tweecer help

1105 · Apr 10, 2005

Last night my car was running good, rich but it didnt backfire or anything but did puff a light cloud of black smoke under heavy acceleration. Today when I took it out the car doesnt want to go anywhere really, it backfires a lot and just loads up leading me to think I'm running really rich, plus the C/E light comes on at idle which would probably be set off by running too rich too. My question is how do I tune the A/F ratio with the MAF transfer function? If I wanted to lean the ratio out by 5%, would I multiply the Y value in the function by .05?

final5-0 · Apr 10, 2005

1105 said:
Last night my car was running good, rich but it didnt backfire or anything but did puff a light cloud of black smoke under heavy acceleration. Today when I took it out the car doesnt want to go anywhere really, it backfires a lot and just loads up leading me to think I'm running really rich, plus the C/E light comes on at idle which would probably be set off by running too rich too. My question is how do I tune the A/F ratio with the MAF transfer function? If I wanted to lean the ratio out by 5%, would I multiply the Y value in the function by .05?

First let me say I use V1.20 so if you use V1.30 then I'm gonna assume things will be about the same.

If you don't have a wb then be cautious and make small changes as you have no way to verify.

You can use the maf or the stabilized base fuel table to change the ratio. IMHO the table is the best way.

To lean out one point of the maf curve by 5% you can take the air flow value and multiply it by .95 or use the utilities section to do it for you.

Know this ...... working with this curve can be kinda tricky. Double check everything and even after saving the file go back and make sure your values are as you wish them to be in the newly saved cal file.

Aslo ...... you'll find that sometimes you call for say a 3% change ...... the value you will see in the cell might turn out to be say 2.5% or 3.25% but not exactally what you called for. Thats just how it is and you just get as close as you can and call it good.

Later
Grady

1105 · Apr 10, 2005

how would you change the ratio with the stabilized base fuel table? Just check multiply by: and set the value to .95 to lean it out 5%? And yes I am going to go in small changes at a time. Maybe like 2% leaner, then another with 4% and see if it keeps getting better.

final5-0 · Apr 10, 2005

1105 said:
how would you change the ratio with the stabilized base fuel table? And yes I am going to go in small changes at a time. Maybe like 2% leaner, then another with 4% and see if it keeps getting better.

You know what ...... I might have given you some crummy info after thinking about your original Q, lol.

You did say you thought your rich at idle and the table I was talking about is for ol conditions.

For what I think you want to accomplish a quick fix would be working with the maf curve cells in the idle range of the curve.

A more permanent solution would be working with the various inj values like slopes, offsets, and the like.

How are you gonna verify your changes?

Later
Grady

1105 · Apr 10, 2005

How am I going to verify? Like to see if it worked? Just take it out for a normal drive and not jump on the throttle, if it stops backfiring I know I'm headed in the right direction.

Which volts would be used for the idle/low RPM ranges for the MAF transfer? I think I might need to change all of them, but just want to start off at the beginning because thats where I know its rich.

final5-0 · Apr 10, 2005

1105 said:
How am I going to verify? Like to see if it worked? Just take it out for a normal drive and not jump on the throttle, if it stops backfiring I know I'm headed in the right direction.

Which volts would be used for the idle/low RPM ranges for the MAF transfer? I think I might need to change all of them, but just want to start off at the beginning because thats where I know its rich.

Seems odd that you say it was running reasonable well and then all of a sudden started all of this back fire like stuff. I saw your pic on the Tweecer site and with all the turbo stuff I was wondering if something besides the tune might be the prob cause why all of a sudded would things change.

Do your data logs show the kamrf's trying to lean fuel out during idle?

Anyway your data logs will show you the range of maf points you use at idle and you would want to work in that range of cells to make your tweecs.

I idle at about .7500 maf volts but I'm na and your pa so that won't help you much.

If I was to guess I'd say you would be a little higher than me at idle like say at 1.0 maf volts due to your turbo but again its a guess.

Later
Grady

1105 · Apr 10, 2005

if I get a data log at idle, could I send it to you to check out? I cant do much more than a log at idle because I have to hook it up to my desktop PC, dont have a laptop yet.

final5-0 · Apr 10, 2005

1105 said:
if I get a data log at idle, could I send it to you to check out? I cant do much more than a log at idle because I have to hook it up to my desktop PC, dont have a laptop yet.

Don't you have a really long ext cord

Sorry I couldn't resist it

Sure ...... pm me for the addy and I'll take a look at it

I wanna see in the datalog values for the following at idle at normal temps:
kamrf (both banks)
lambse (both banks)
pulse width (both banks)
rpm
spark
mafV
maf
loadX
load
tp

Later
Grady

1105 · Apr 10, 2005

yes I do have a long cord, thanks for noticing The comp sits right next to the back door. I'll get thoes loged for you

final5-0 · Apr 10, 2005

1105 said:
yes I do have a long cord, thanks for noticing The comp sits right next to the back door. I'll get thoes loged for you

I have heard of peeps using a long cord so they can get to the home pc to tweec and it seems you are one of em

I LOVE IT

It seems that small things don't stop you from your objective

Later
Grady

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