Tweecer/Tuner guys, help with A/F at idle

[zenboy99]

Well, it looks like you guys were right, it was the MAF transfer. I changed the MAF values and its down to 14.5-15.0 at idle.

I looked back over my different MAF transfer functions and it seems the low values at idle didn't change very much over the course of the datalogs that I ran. I wonder why my car wasn't adapting to a lean idle? could it be that it was so lean that it was beyond the computer adapting? Everything is dead on driving around though.

This is a great website, you guys always seem to help me see the whole picture of things and give an alternate view. And everytime something bad like this happens, I learn a little more about my car.

 

[Black95GTS]

Hey Adam

You realize that you and I are doing the very same thing but kinda from a different direction

We both will arrive at the same result because ......

LAMBSE & KAMRF mirror each other.

Where you look for what the LAMBSE is doing shortly after a pcm reset ....
I do the same with the K's.

IMHO, you have come a long way in a short time

Grady

Yeah, I have to say, I was thinking about this and I realize its basically the same thing. I guess I looked at it my way, as an advantage, because I could see the LAMBSE straight away while you had to run it a bit to take the K values. But yes, we are going to arrive at the same result.

Thanks for the compliment, that means a lot coming from a vet like yourself!

I consider myself somewhat knowledgable.... but this spring time, I will be adding a 75mm TB, 80MM MAF, and 30lb injectors to handle a 125 dry shot. I will be bugging the heck out of you! So get ready! I want to have a 12 second car before I do heads and a cam. After I do H/C, I want to have a mid to low 11 second runner on 93 pump gas and a TwEECer tune!

To Zenboy99: Congrats on figuring the problem out! The MAF transfer is an amazingly powerful function. I haven't had the (dis)pleasure of having to figure it out since my mods aren't beefy enough to warrant it. But pretty soon I'll be posting similar threads to yours! Good luck and good driving!

Adam

 

[final5-0]

I consider myself somewhat knowledgable.... but this spring time, I will be adding a 75mm TB, 80MM MAF, and 30lb injectors to handle a 125 dry shot. I will be bugging the heck out of you! So get ready! I want to have a 12 second car before I do heads and a cam. After I do H/C, I want to have a mid to low 11 second runner on 93 pump gas and a TwEECer tune!

Adam

Things are gonna change BIG TIME with those upgrades

Your gonna have a good time

and

Most Definitely learn a new trick or two

Grady

 

[final5-0]

Well, it looks like you guys were right, it was the MAF transfer. I changed the MAF values and its down to 14.5-15.0 at idle.

I looked back over my different MAF transfer functions and it seems the low values at idle didn't change very much over the course of the datalogs that I ran. I wonder why my car wasn't adapting to a lean idle? could it be that it was so lean that it was beyond the computer adapting? Everything is dead on driving around though.

This is a great website, you guys always seem to help me see the whole picture of things and give an alternate view. And everytime something bad like this happens, I learn a little more about my car.

Hey Mr. Chad

How much did you have to change the maf points?

Grady

 

[VibrantRedGT]

Even though I'm a PMS user this thread is a great read. Glad it all worked out.

 

[zenboy99]

Hey Mr. Chad

How much did you have to change the maf points?

Grady

Stock values from my flowsheet were:
0.7998---26.40
1.0000---35.204

Over a dozen datalogs and the 0.79 value never changed in EEC analzyer even though I was idling at ~0.85 volts.

New values:
0.7998---32.0
1.0000---37.5

 

[zenboy99]

Just posting this up for more info.

I've been playing with the lower MAF transfer function all week. Now that I have the idle running about normal, the KAM's are changing at idle. So maybe my problem before was that the car was so lean that the KAM values weren't changing at all? The computer couldn't/wouldn't adapt to the lean idle? I have another local friend who said he experienced the same thing.

 

[final5-0]

Just posting this up for more info.

I've been playing with the lower MAF transfer function all week. Now that I have the idle running about normal, the KAM's are changing at idle. So maybe my problem before was that the car was so lean that the KAM values weren't changing at all? The computer couldn't/wouldn't adapt to the lean idle? I have another local friend who said he experienced the same thing.

No maybe to it at all Chad

If you are too far out of range, as far as fat or lean, the adaptive does not behave as it should.

Now you are getting in the range, here are a few things to consider that can effect closed loop operation.

slopes
breakpoint
offsets
maf point
tb air flow
neutral idle air flow

there are others to be sure
but
those are the biggies that come to mind right off the bat

good to see you making progress

Grady

 

[zenboy99]

good to see you making progress

Grady

I'm a Tweecer junkie. My wife told me that in the last week I've spent more time in the garage with my car than with her. I told her its better than me dishing out attention to a hooker, sometimes your car needs some lovin' too.

Speaking of car lovin', I just got my first ever allignment 179,000 miles then a new coil-over strut install screwed things up pretty good. Wow is the car nice to steer now.

 

[final5-0]

I'm a Tweecer junkie. My wife told me that in the last week I've spent more time in the garage with my car than with her. I told her its better than me dishing out attention to a hooker, sometimes your car needs some lovin' too.

No doubt about ........... you're hooked now

You suddenly realize ...... Look at all this data I've gathered

Then you start to ask yourself Q's that always begin with these words

I wonder if ...........

Yep .......... You've crossed the point of No Return

No Turning Back Now for You Chad

Grady

 

[blksn955.o]

ya dude your ***t.