tweecer users please help

To adjust your WOT Air fuel ratio the best be would be the top part of your MAF curve or what i use which is the Stabilized_OL_Fuel or something like that in the tables section.

i had a situation like that a few weeks ago. i had my min_inj_pulsewidth to high. i dropped the pulsewidth down to .0003 after reading some threads. now the computer controls the pulsewidths and i'm not rich at idle anymore.

AUcobra94 said:

I datalogged the car last night and its around 12:1 air fuel at idle. My question is what table or function do I change for idle and normal driving?

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Was the 12 to 1 value from your wide band or was this a lambse value that you saw in your dlogs?

Here are a couple things you could do here Dan to change idle fuel conditions

1) You can work with your inj low slope value
higher value will lean things out
lower value will fatten things up

2) You can work with your maf curve idle point and maybe one before & one after that point. Up the airflow value to fatten and Lower the value to lean.

btw, if you saw a lambse value of 12 to 1 at idle then you are too lean. The pcm is commanding a rich ratio to try and compensate.

The second question is for WOT I think the table is WOT_fuel_multiplier-v-RPM, is that table right? In this table(WOT fuel mult-v-RPM) the RPM settings are all at 0 and the fuel mult settings are all at 1. Should I add the rpms? thanks Dan

PS I live in Auburn Alabama and if there is anyone close to there that would be willing to help me or just talk to me on the phone about it,I shure would appriciate it.

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As John said above, the stabilized fuel table is what most 94-95 guys I know about use for WOT fuel adjustments.

You see WOT_fuel_multiplier-v-RPM used by the fox guys alot. I'm not saying that won't work but I don't recall ever seeing anybody with our cars use it.

Just in case you may not know and for safetys sake of your combo ..........
You need to work with a wide band for WOT final fuel ratio adjustment.
Lambse values seen in your dlogs are not accurate and can not be trusted for this part of tuning.

Grady

IIRC the only time I have heard/seen about the fuel v rpm table being used on our 94-95's was with boost as a way to make it richer (over the commanded stablized OL table) on our 94-95's.

I realy dont see the need though as the fuel stablized OL is preaty good...but maybe the safty for the boost may be what they are looking for??? I am not boosted so I dont realy get into that side of tuning.

For idle you will want to look at your MAF curve and inj. slope/breakpoint/offset.

It would also be a good idea to post a detailed list of mods...MAF, Inj. size, processor file your using, Fuel Press. setting.

IF your running a 30lb inj. or larger you might want to look at some of final5-0's posts in a search about running forced CL at idle to keep the eec from "drifting" over time.

But first you should focus on MAF and inj... Eec Annalizer will help get that down quickly if you dont have that program already.

E.A. should be bought the same day the tweecerR/T is bought if you ask me.

yes, you load a DL into it and it "crunches" the data. The help files and Clint the guy who made it are very helpfull.

You can download the program for free and look at it, but in order for the calculations to work you have to purchase a reg. code to activate the program fully.

AUcobra94 said:

Thanks everybody. I am using the lambse, and the real concern is the car being extremely rich at idle. Ill play with the fuel stabilized at OL and see if I can lean it out. I knew the lambse were not accurate but do they usually read more lean or rich? They read 11:1 at WOT at around 5000 rpm. So I can use the Fuel_stabilized_OL table to change air fuel from Ilde through WOT?

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Dan

If you are seeing lambse values of 12 to 1 at idle you are lean.

At idle you are in Closed Loop conditions. The Lambse value of 12 to 1 is what the pcm is asking for or commanding to try and achieve a ratio of 14.7 to 1

The fact that Lambse is lower means the pcm is asking for a fatter ratio.

You also can look at your KAMRF's which is the adaptive strategy or a fuel trim if you will. If everything was right on the money at idle, you would see the K's at a value of 1.00

K's > 1.00 = adaptive adding fuel to compensate for lean conditions
K's < 1.00 = adaptive pulliing fuel to compensate for fat conditions

btw, K's only come into play during CL conditions.

I'm not trying to be a hard case kind of guy Dan
but
fuel tables is one of the places you can do some damage and I really am wanting to make sure you see this from the perspective of how the pcm deals with fuel.

Lambse values seen in your dlogs is NOT your af ratio
Lambse values seen in the fuel tables is NOT necessarily your af ratio

If you had a wide band
AND
You adjusted your fuel table and maf curve where they matched your wide band values
Then
You could use the Lambse values in the fuel table to choose your final af ratio

Still one more way to look at what we are talking about here is like this

Values in the fuel table are what the pcm is going to try and command.

If you got different maf, inj's, etc ....................
Things could be off in the tune ................
Even though you see 11.7 in the fuel table ...................
That don't mean 11.7 is what you are gonna get......................

Only a wide band is gonna let you know what you really got during WOT.

If you are too lean at WOT ... damage could happen

Grady

blksn955.o said:

IIRC the only time I have heard/seen about the fuel v rpm table being used on our 94-95's was with boost as a way to make it richer (over the commanded stablized OL table) on our 94-95's.

I realy dont see the need though as the fuel stablized OL is preaty good...but maybe the safty for the boost may be what they are looking for??? I am not boosted so I dont realy get into that side of tuning.

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To the original poster, from my experience: One of the hardest things that I had to get into my head when TwEECing our computers is how they determine load. On a FOX, RPM is used to determine load. Pretty easy. But on an SN95, air flow is. Its an entirely different philosophy and one of the reasons our computers are so damn tricky.

This is why the FOX guys use the fuel vs. RPM table, and why its not as useful for us except in special circumstances like the one listed above.

Adam