NEW IAC Berrel Auto?

[berrelauto]

I am told that I will have 14 more Buick adapters next week, they are being shipped to me today. If anybody wants to reserve any call us and give me your name and payment information and this will guarantee that you receive one from the first run. Also you can call your favorite Buick vendor most will be stocking them. Thanks for the interest.

 

[Otto J]

I bought mine from Dale at the NAts,My iac must have been bad as i have way better control over idle quailty.And it reacts way faster tahn the old peice
Thanks Dale

 

[berrelauto]

I just received 14 of the Buick IAC adapters so whoever is interested, contact me as soon as possible, I don't think I will have these in stock long. We are offering these at $199 for the kit with free ground shipping to the lower 48 states.

 

[berrelauto]

If you want to pay with PayPal, send the payment to berrelauto@yahoo.com

 

[bruce]

Installed mine today.
Completely Plug, and Play. Excellent fit and finish (satin).

It's about .9" shorter then the oem one, so it leaves a fair amount of room for the Turbo Intake Plumbing.
I'd never really studied the later IAC's, but there are several design improvements.

It works for me....

 

[norbs]

ANyway to measusre response time?

 

[bruce]

Originally posted by norbs
ANyway to measusre response time?

Sure, a real good O-Scope, and a Stepper motor driver circuit.

But, what does it really matter?
Here's a snippet of code from an IAC routine. Note, this is also for a non A/C car, so it's alot more streamlined then what you'd normally see in a oem application.

While the aftermarket codes might be somewhat simplier, there's still so much going on, that nothing's going to happen instantly. I don't know if the aftermarkets run their code in loops or just in continually repeat the code from end to end, there still is going to be a limit to how often the code for the IAC is read, and acted upon.

While an aftermarket company might not let you see/edit the filtering that goes on, they probably use some form of PID to make the RPM corrections, and that code also takes time to run.

* IDLE AIR CONTROL CONSTANTS AND TABLES
* IAC Parameters
; 'COEFF' RPM/12.5 FILTER CONSTANT
; 'SECS ' LENGTH OF TIME FOR HOT SPARK RETARD, SEC
; '%TPS' THRESHOLD BELOW WHICH ISC IS ENABLED
; 143 steps, motor park position
; 0.5 sec's, stepper motor pk to run delay, sec/80
; 650 rpm/12.5 pwr steer stall saver
; 700 rpm/12.5 to exit pwr steer stall saver
; small error extend, idle too hi
; large error extend, idle too hi
; small err retract, idle too lo
; large err retract, idle too lo
; 50.0 rpm, idle hi bk pt for large gain wd
; 37.5 rpm, idle lo bk pt for large gain wd
;* 12.5 rpm, dead band
;* extend pulse reset steps
;* 8.7 vdc, stepper motor protect
;* 25, DFCO step's, added when in
;* 8 steps, fan bump
; 1 step, pk/neut position diff
;* 0 steps incr for batt vdc decrease
;* 0.2vdc batt decr for incr steps
;* max iac
;* low vss TF decay filter coef
;* med vss TF decay filter coef
;* hi vss TF decay filter coef
;* .0 sec, TF decay delay for low vss sec/5
;* .0 sec, TF decay delay for hi vss sec/5
;* decay filter coef, DFCO not active
;* decay filter coef, DFCO active
;* decay filter coef, for stall saver
;* 6 steps, min TF val at > lo vss
;* %tps for TF bias
;* max TF, steps


BTW, if anyone wants to make an IAC controller, Rainbow Electronics used to make a *learning kit* that used a design that works with a GM stepper motor (IAC).

 

[berrelauto]

We got the remainder of our intial run of the Buick IAC adapters. So we have plenty in stock as of now. We are extending the introductory pricing of $199 ground S/H included to the lower 48 for the rest of June. We also have the IAC adapters for Ford style throttle bodies for custom applications. Introductory pricing is the same.

 

[bruce]

Now that I've had the new IAC on for a few days, and played with some of the IAC lag filters, and decay rates, all I have to say, is:

IMO, THIS THING ROCKS ! ! !!!

Thanks, Chris!

 

[norbs]

I got mine the other day, thanks. However i am have some issues of a rougher idle between transitions between Park and drive. Will have to play with the PID gains i guess, maybe its too sensistive now? As in the gen 7 you have many settings for the iac.

 

[bruce]

Originally posted by norbs
I got mine the other day, thanks. However i am have some issues of a rougher idle between transitions between Park and drive. Will have to play with the PID gains i guess, maybe its too sensistive now? As in the gen 7 you have many settings for the iac.

Cutting some of the max IAC counts almost in 1/2 seemed to help with some of that, in my code.

FWIW, my max reset is now 75, and max opening only 45.

I'm also running a min IAC of 4-6, at idle, with a rock steady idle, ie even better then a forced 0 count.

Dunno, if this directly helps you, but it might give you a nudge in the right direction.

 

[norbs]

Thanks, on the dfi you have an "idle attack rate" i may have it set to aggressive. The clearance to the 4" inlet pipe is great. i am wonderin if the gen 6 dfi's will work better as the iac control is very lazy in a gen 6

 

[norbs]

I have found a new issue that i am running into with this new iac. I have to turn the idle screw almost all the way out , now the throttle body is sticking on the plate, becuase of the decreased angle. The iac flows alot of air, and my counts are almost close to zero to get a low 800 rpm idle. This maybe due to a 70mm throttle body though. Any suggestions?

 

[bruce]

Originally posted by norbs
I have found a new issue that i am running into with this new iac. I have to turn the idle screw almost all the way out , now the throttle body is sticking on the plate, becuase of the decreased angle. The iac flows alot of air, and my counts are almost close to zero to get a low 800 rpm idle. This maybe due to a 70mm throttle body though. Any suggestions?

Clean up the throttle body, and butterfly. Then using a Magic Marker, blacken the outside perimeter of the butterfly. Snap it open and closed a few times. Then with a jewlers file, CAREFULLY file the shiny posts. Repeat the coloring, resnap the butterfly again, and repeat as necessary, until you can't see any light between the butterfly and housing. You also need to watch the *taper* on the butterfly as it changes, as the butterfly closes further and further.

Can take hours to get it *right*.

 

[norbs]

I wonder if Dale could just add the option of drop in restrictors in the housing for such low air-flow applications.

 

[bruce]

Originally posted by norbs
I wonder if Dale could just add the option of drop in restrictors in the housing for such low air-flow applications.

I'd imagine they'd coke-up easily. Some engines, get the IAC and the byass channels rather gooey.

Are the IAC counts rather low to begin with?, if so then much of anything in the way of restrictor, would mess up the intial high IAC settings for priming/starting the engine. You need a rather large volume of air to get then intial *run*. BTW, if you can data log the engine as it goes from crank to run, you can see how long it takes for the engine to actually pump down the plenum, from atmospheric pressure.

 

[bruce]

BTW, just how much timing are you running at idle?.

 

[norbs]

I like to run around 30 degrees. The counts are very low the gen 7 only goes form 0-100 counts. Its around 2-3 counts at idle with the tb screw backed fully out.

 

[bruce]

Originally posted by norbs
I like to run around 30 degrees. The counts are very low the gen 7 only goes form 0-100 counts. Its around 2-3 counts at idle with the tb screw backed fully out.

Might try 22-24d. Running that much timing at idle, can be covering other problems, ie not having the AE or VE table quite right, or so I've heard.

It'll also reduce the likely hood of having tip-in pre-igntion.

 

[norbs]

Bruce, can you post a copy of the stock timing map somehow?