Idle and Driveability

teal_94gt

New Member
Dec 7, 2004
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OK, I have started over from scratch several times. I have recently just started from scratch and pretty much only have my maf curve dialed in as well as the injector slopes. Everything else is stock except for my spark base table and the others turned off. I have absolutely no bucking but every once in a while it is hard to start after it's been driven. And my sometimes goes to 1100 down to 900 but for the most part is stable and does not surge. My Lambse?(sp?) reads at idle when starting up down to 10 to 11:1. I don't have any luck using eec analyzer for isc idle settings, some luck manually; but then I create bucking. How do you datalog 100 rpm incriments steady to create the isc neutral idle airflow table? I seem to have better luck doing the idle manually and leaving the settings alone. Any pointers? Thanks, Justin
 
I'd like to and I am willing to work with you :nice:
but
Please don't take this the wrong way :D

You gotta get rid of that ... generic phrase ... "all bolt ons"
that just don't tell me squat :nono:

Please get specific with your sig mods ;)

Grady
 
Bolt-ons: Pro-M 77mm MAF(actual flow sheet loaded in), BBK fox 75mm TB, MAC 1 5/8'' LT's, VRS o/r x-pipe, stock mufflers, pulleys, no egr or smog pump, and 24lb's. This is mostly what it consists of the basic supporting mods plus suspension, stiffening, etc.
 
Methodical said:
I used filler gauges to raise my rpm as close to 100 rpm as possible. I slipped them under the screw on the TB plate. It's not exact but was as close as I could get it.

Do you do seperate datalogs for each rpm then also to build the table? Thanks, Justin
 
Thanks for the complete setup Justin :D

It helps me to see the big pic :nice:

You are too lean
cause
Lambse is commanding fat

I bet your K's are showing > 1.00

You are using the 24lb default j4j1 offsets ... right?

You don't have to follow those exact rpm values in that neutral idle airflow function

Heck ... my 95 won't even idle that low :)

Cruise over to my site and find the file you can dl

It's made from screen shots of my current file next to an unmodified j4j1. The parts of the file you don't see are unchanged or the same as the original j4j1 values btw.

You can clearly see what I'm talking about with that file :nice:

You might wanna check out tb airflow

You might wanna check out isc duty cycle

btw ... +1 on the old feeler gauge trick from above :nice:

To arrive at values for the airflow function ........

I just did one dlog capturing to hd while using the fg's to give approximate desired idle rpm.

I then threw the dlog into Excell and used its excellent filtering capabilities to find my range of desired values.

Your maf points around idle may not be all that close :shrug:

Those are some of my thoughts :)

Your turn Justin :D

Grady
 
Grady-
My K's on startup are larger than 1, so this means it is lean correct? Smaller than 1 means it's rich then? Am I correct on this? Yes I am using stock 24lb inj. offsets. Thanks for the resource and data to look at. How does ISC duty cycle need to be computed. I understand how to do the neutral idle airflow, and then figuring out the idle in neutral and in gear once you have the figures.
 
OK Justin

Here is some basic info that may help you and others :D

The af ratio is nothing more than ............

So many parts of air to one part of fuel
and
14.7 parts of air to 1.00 part of fuel is what the auto biz considers to be stoich (sp) :shrug:

16.00 to 1.00 would be lean as the fuel is diluted more
12.00 to 1.00 would be rich as the fuel is diluted less

btw ... these are values you would see on your wide band

About those lambse values :)

lambse is NOT your af ratio
lambse IS the commanded or asked for af ratio by the pcm

Example:

You see a section of L values in your dlog that show 15.5

This means you are fat at that particular time
BECAUSE
The pcm is commanding a ratio that is lean
and
that > 14.7 value is the pcm trying to compensate

Of course ... L values < 14.7 would be the opposite

About those kamrf values :)

The K's are values that show you the pcm's adaptive fuel strategy at work.
This strategy is at work during Closed Loop conditions only btw

It has a range of 25% but I myself, think of it more like 12.5% :D

A K value of 1.00 is considered to be perfect or there is no + or - fuel correction kind of thing going on. A kind of a null or void value if you will as the adaptive is not at work.

At a 1.00 value ... you can only go 12.5% in either direction ;)

Example:

You see a section of K values in your dlog that show 1.05

This means you are lean at that particular time
BECAUSE
The adaptive is adding 5% fuel
and
that > 1.00 value is the pcm trying to compensate

Of course ... K values < 1.00 would be the opposite

About the isc duty cycle ............

Sift through the text on the tuning page of my site. IIRC, I put up some specific details about that subject as well.

Yes you would wanna do a pcm reset when working with idle issues.

For that matter ........ You usually want to do the reset thing for most ANY kind of C L efforts when working on your file.

I almost forget ..........

You ask about start up.

You are not in C L when you first start your car. You do get there, but that happening is dependent upon time and ECT.

Don't be mislead in that area as it is easy to do. Be sure your K's are active when working there.

On the pcm reset ............

You ought to disco the neg cable my friend :nice:
to avoid
The underwear soiling SPARKIE EVENT :rlaugh:

Hope this helps :)
and
Holler if any of this stuff don't make sense ;)

Grady
 
Do you do seperate datalogs for each rpm then also to build the table? Thanks, Justin

Hey Justin I apologize for not responding as I now realize that I did not "subscribe" to this thread.

I datalogged the 100 rpms from 500 rpm to 2000 rpm just as stated in EA. One thing to note though is my headers go hot and red as hell and melted my spark wire looms and damaged my clutch cable (too close to the stubbies). I captured the info in one datalog, then input the info into EA and did some average - similar to what Grady said. EA suggest a high TB # when compared to others but has worked.

Tip: To clear KAM, you do not need to disconnect the battery everytime. Here's what you do. Set a bad tune to one of the switch positions, preferably #4 spot (more later on that). Basically just install an A9l tune to position #4. Now whenever you need to clear KAMs, you just switch to the #4 position and turn the key on engine not running and the fuel pump will prime and the fan will turn on, whoila, the KAMs are cleared. Now let's get back to why the #4 position and not the #1 position. You do not want to set the bad tune to the #1 position because it is the default position if the switch was lost or damaged etc. So if you have the bad tune there, guess what, correct - you can't start the car. Oh by the way you can also use that position as a antitheft device - example: switch to the #4 position and the would be thief can't get the car. I've read where some put the bad tune in the #1 position and pull the switch as an antitheft device. I would suggest againt doing that though.

Tip 2: I put the good tune to the #1 position and experimental tunes to the 2nd and 3rd positions and bad tune to the #4 position.

Oh, I am "subscribing" now.:D
 
Tip: To clear KAM, you do not need to disconnect the battery everytime. Here's what you do. Set a bad tune to one of the switch positions
I loaded an A9L (Fox EEC) onto my switch (position 1 :) ) and use that to clear the KAM and act as theft deterrent.

You can get a copy of the A9L binary from here: http://www.moates.net/zips/boothware/

I don't remember if I changed my strategy in CalEdit to load it up or not.

When you do switch to the A9L tune and put the key in the ON position your fans and your fuel pump will run... turning the key won't do a darn thing though.

I keep my copy of A9L on position 1 so that I can put the switch panel in my pocket if I leave my car in a bad part of town.

I figure if my twEECer ever screws up or I lose the switchpanel I can a) remove the kickpanel and yank the twEECer off the EEC or b) if the twEECer is screwed up my car wouldn't be driveable anyways so I'm stuck anyways. I think twEECer failures are pretty few and far between. But it all boils down to a matter of preference.