My Flat Tappet Cam Wiped Out So I Decided To Go Roller

[L31MaxExpress]

Nothing for airflow though for over/undershooting idle speed, huh? It's all MAP and not mass airflow back then I suppose.

All IAC steps no complex airflow/torque model being used with IAC steps vs flow tables, etc.

 

[Supercharged111]

All IAC steps no complex airflow/torque model being used with IAC steps vs flow tables, etc.

I must have missed that? All that caught my eye was that timing modifier for over/under shooting desired idle RPM.

 

[PlayingWithTBI]

I must have missed that? All that caught my eye was that timing modifier for over/under shooting desired idle RPM.

Probably, here's my reply to your question earlier. I've been trying to control IAC Stall Saver to keep it running when I drop it in gear. Now we're trying SA too. In my data logs, it looks like they both jump up when it surges and/or when I put it in Reverse.

My Flat Tappet Cam Wiped Out So I Decided To Go Roller

I like the digital dash. That's slick.

www.gmt400.com

 

[L31MaxExpress]

Probably, here's my reply to your question earlier. I've been trying to control IAC Stall Saver to keep it running when I drop it in gear. Now we're trying SA too. In my data logs, it looks like they both jump up when it surges and/or when I put it in Reverse.

My Flat Tappet Cam Wiped Out So I Decided To Go Roller

I like the digital dash. That's slick.

www.gmt400.com

Been a while since I have messed with the Dynamic EFI code. Seems like I remember an IAC step adder for In-Gear. There is also one for AC as well as for an electric fan that is ECM controlled. You set your IAC Base Steps table for what it idles at. If you have the ac relay in place the IAC will step the idle up prior to the ECM commanding the ac clutch relay on. From mempry with the ac clutch being controlled you can also add a turn on delay after the system requests the ac on.

 

[L31MaxExpress]

Remember also on a TBI the IAC is a vacuum leak. You want the throttle plate open enough to only have 5-10 IAC steps at hot idle in Park with all the heavy electrical loads and AC off.

Timing will also respond more quickly that the IAC for idle stabilization. As RPM error increases you want more timing added or removed. +/- 25 RPM I would have the idle spark compensation at 0, then at 50 rpm maybe 1-2* with accounting for the multiplier at the MAP you are idling at. The MAP multiplier as setup in your screen shot is exactly backwards from how I would have it set up. In neutral at low load the engine will be more sensitive to timing changes at lower maps. In gear with a higher map or with the ac on with higher map it is going to take more of a timing change to get the desired results because the airflow through the IAC will be higher and the engine making more torque because of it.

 

[PlayingWithTBI]

Remember also on a TBI the IAC is a vacuum leak. You want the throttle plate open enough to only have 5-10 IAC steps at hot idle in Park with all the heavy electrical loads and AC off.

I have it pretty much there. The IAC responds when I put it in gear and/or turn on the A/C so, it appears to be working as it's told. I just don't know where to tell it so

 

[Supercharged111]

Probably, here's my reply to your question earlier. I've been trying to control IAC Stall Saver to keep it running when I drop it in gear. Now we're trying SA too. In my data logs, it looks like they both jump up when it surges and/or when I put it in Reverse.

My Flat Tappet Cam Wiped Out So I Decided To Go Roller

I like the digital dash. That's slick.

www.gmt400.com

Stall saver isn't what I'm thinking of. It could be that this old dinosaur just doesn't have it. Does the EBL have idle trims or not? Stall saver is, in the 411, to prevent a stall and not jump in for a slightly wandering choppy idle otherwise acting normal.

 

[L31MaxExpress]

Stall saver isn't what I'm thinking of. It could be that this old dinosaur just doesn't have it. Does the EBL have idle trims or not? Stall saver is, in the 411, to prevent a stall and not jump in for a slightly wandering choppy idle otherwise acting normal.

It has a stall saver, but best plan of action is not to activate it if you can keep from it. Activating stall saver too easily can directly cause a surging idle.

 

[L31MaxExpress]

The EBL code also has IAC acceleration enrichment fuel that needs to be dialed in to prevent a lean spot as the IAC opens. By shooting fuel as the IAC adds airflow you are not relying on the heavily filtered MAP AE to possibly add a bit of fuel with a large IAC opening change.

 

[L31MaxExpress]

I have it pretty much there. The IAC responds when I put it in gear and/or turn on the A/C so, it appears to be working as it's told. I just don't know where to tell it so

The easiest way I found to do it was compare steps after it stabilized. If it is at say 5 steps, turn the ac on on and it jumps up to 20 steps, you want say 15-20 steps with the ac added. Overshoot a bit and let the ecm logic pull a few steps. Better to have it idle a little high than to stall out until you get the tune closer.

Same with the P/N to In-Gear transition.

I also prefer to idle a little higher in Park/Neutral than In Gear. It helps smooth the transition out.