IAC counts

[hquick]

Can someone please tell me....
When in park...engine at op temp...what should IAC counts be?
When in gear...engine at op temp...what should IAC counts be?
Is it a matter of adjusting the set screw to get the counts into the correct range?
In gear...I'm seeing around 57 counts. In park....I'm seeing as low as 7 counts.

Thanks

[SSpdDmon]

It's been a while since I've worked with an A4. I'd say, try adding a little timing for idle in gear. This may help bring your IAC counts up some and reduce the delta. Then, I'd target ~50 steps for in park and ~80 steps for in gear. Basically, you want enough padding below your current steps to be able to allow the IAC some control in the event it needs to block airflow to the engine.

[hquick]

So....I should first set the blade to fully closed and then reset the TPS?
How do I actually increase/decrease IAC counts? Just by adjusting the set screw?

Thanks

[SSpdDmon]

I would use the bi-directional controls and slowly close the blade with the set screw until you see the IAC counts creep up. Closing the TB increases the IAC counts and opening the TB reduces them. You shouldn't need to mess with the TPS sensor.

[hquick]

OK....rain finally stopped for 10 mins so I decided to tackle the idle issue
Closed the TB completely (wound the screw right out) and then just wound it in enough to make sure the TB blade wasn't sticking.
I then 'reset' the TPS and the IAC and started logging.
At fully warm idle....in park I tried to get the IAC steps to 50 and 80 in gear.
I added one or two degrees of timing and then played with desired airflow.
I can't seem to get the IAC counts above approx 55 and 75. If I do...the Burb has alot of trouble finding idle on a re-start and will mostly stall.
It seems to be good at 55 and 75.

[macca_779]

Howard I'm not a fan of messing with the set screw as if you open it enough it will eventually give false TPS values. Rather I drill out the base hole in the Throttle blade. I just work up slowly until I get a result where idle can be maintained with approx 70 steps.

[hquick]

Thanks Macca.
There's alot of talk about 'to drill or not to drill'.
These TB's don't actually have a hole at all.

[5.7ute]

Hi Howard. To get my iac counts where I wanted them involved both adjusting the set screw & opening the hole in the throttle blade slightly. As sspdDmon has stated you want the iac counts where they have best control over airflow, between 40 to 80 counts. But remember that this is just a base position for the iac valve to go to. Idle speed is mainly controlled by timing as the iac moves too slow to have any real effect on this.

[SSpdDmon]

OK....rain finally stopped for 10 mins so I decided to tackle the idle issue
Closed the TB completely (wound the screw right out) and then just wound it in enough to make sure the TB blade wasn't sticking.
I then 'reset' the TPS and the IAC and started logging.
At fully warm idle....in park I tried to get the IAC steps to 50 and 80 in gear.
I added one or two degrees of timing and then played with desired airflow.
I can't seem to get the IAC counts above approx 55 and 75. If I do...the Burb has alot of trouble finding idle on a re-start and will mostly stall.
It seems to be good at 55 and 75.


Hi Howard. To get my iac counts where I wanted them involved both adjusting the set screw & opening the hole in the throttle blade slightly. As sspdDmon has stated you want the iac counts where they have best control over airflow, between 40 to 80 counts. But remember that this is just a base position for the iac valve to go to. Idle speed is mainly controlled by timing as the iac moves too slow to have any real effect on this.


WERD...the numbers I threw out were merely targets. If you hit 55/75, you're there.

If you're having startup stalling issues, try adding a little airflow to the startup friction tables under idle>startup for the coolant temps where you're seeing problems.

[hquick]

Thanks again.
When I start the Burb when warm (cold starts are fine) rev's go high....low (almost stalling)...high...low until it settles.

[SSpdDmon]

Thanks again.
When I start the Burb when warm (cold starts are fine) rev's go high....low (almost stalling)...high...low until it settles.
If they go too high above desired idle, the Direct Airflow Correction table's high idle columns will pull airflow. They may be pulling too much.?.?.

On a work computer, so I can't view your tune. Sorry.

[hquick]

Thanks for the ongoing tips.
Tried a few other things today. Altered most of my settings as per your idle tutorial and it helped alot. Hangs a little on start up.
IAC counts look better.
A couple of questions:
Tried doing a RAFPN but for some reason got no numbers in the map whilst logging. I got logged counts but no corrections.
I've done the RAFPN ALOT of times before...even yesterday with no issues???
One more question....alot of tunes seem to have all 1.0's in the follower multiplier table. Yours in that idle tutorial doesn't. Why/not?

Thanks

[SSpdDmon]

Thanks for the ongoing tips.
Tried a few other things today. Altered most of my settings as per your idle tutorial and it helped alot. Hangs a little on start up.
IAC counts look better.
A couple of questions:
Tried doing a RAFPN but for some reason got no numbers in the map whilst logging. I got logged counts but no corrections.
I've done the RAFPN ALOT of times before...even yesterday with no issues???
One more question....alot of tunes seem to have all 1.0's in the follower multiplier table. Yours in that idle tutorial doesn't. Why/not?

Thanks

When doing the RAF stuff - I've always done it manually. In other words, I check the STIT and LTIT averages. Then, do the math myself. Call me paranoid. Still on my work computer though. Did you make sure those pids were reporting back values?

As for the throttle follower multiplier - I recommend starting from an '01-'02 f-body's tables. They were set from the factory with multipliers greater than 1.0. I like 'em better because all you have to do is play with the multiplier and decay. No fussing over the actual airflow numbers. :)

The hanging on start up sounds like you have a touch too much airflow somewhere. Keep an eye on the various airflow PIDs and the problem should reveal itself.

[hquick]

Thaks again.
I just logged from cold start (well...as cold as it is here - 16oC at 5am).
I got readings in the 20, 32 and 44 columns but after that they were all 0's.
Would it have something to do with learning being enabled?
Anyway...idle in gear is very smooth. In park needs some attention as there is a slight stumble (nothing too serious).
Lowered the cracker airflow slightly and that seems to have fixed the slight 'hang'.
I've read in a couple of places that all spark tables (guessing...high and low octane B5915 & B5914...along with base spark in and out of gear B5932 & B5933) should be the same in the idle area's.
What are your thoughts on this?
Mine are as follows at the 800rpm, 0.16 grams point:
B5913 - 28.9
B5914 - 28.9
B5932 - 23.0
B5933 - 19.0

IAC counts are now pretty much 50 in park and 80 in gear.

Thanks

[SSpdDmon]

Thaks again.
I just logged from cold start (well...as cold as it is here - 16oC at 5am).
I got readings in the 20, 32 and 44 columns but after that they were all 0's.
Would it have something to do with learning being enabled?
Anyway...idle in gear is very smooth. In park needs some attention as there is a slight stumble (nothing too serious).
Lowered the cracker airflow slightly and that seems to have fixed the slight 'hang'.
I've read in a couple of places that all spark tables (guessing...high and low octane B5915 & B5914...along with base spark in and out of gear B5932 & B5933) should be the same in the idle area's.
What are your thoughts on this?
Mine are as follows at the 800rpm, 0.16 grams point:
B5913 - 28.9
B5914 - 28.9
B5932 - 23.0
B5933 - 19.0

IAC counts are now pretty much 50 in park and 80 in gear.

Thanks
Weird. Wonder why that is.?.? Maybe it's dead nuts on and your precision isn't showing enough decimals? I'm guessing now...

Did you try looking at the PIDs themselves on one of the charts (f10 - tab b)? You can switch the PIDs by right clicking on one of the existing ones and changing it to what you want.

As for timing - you first want to find what it wants to idle at best. I'm not familiar with the standard Suburban setups. But, on the f-bodies, I believe the autos idled with ~22 degrees in P/N and ~28 degrees in gear. In an A4 application, the idle region of the in gear and high/low octane tables should be the same. This helps keep the transitions on/off throttle smooth.

[hquick]

When I watch the PN pid on the chart it starts at 2.63 and gradually drops down until it hits zero and stays there. I find it hard to believe I could have it that close.
Is there a way to increase the decimal points in the log?
I'll play around with the timing a little.
Just as an FYI...mine is far from the standard Burb setup.
Custom Whippled, marine intake with 42lb Bosch Greentop injectors.

[joecar]

On the chart (chart "stripe") that the pid appears, do rightclick->Properties->Series and under Format change the number after the decimal to 3 or 4 or more (but leave the rest of the format string alone): e.g. %.3f