Desired Idle Calculations?

[don3194]

16197427 ECU, $OD 5.7 tune adjusted from BJYL base using XDF and ADX from 16197427 thread on here.
I've just started tuning and been playing around a bit. I'm using the excel document Dave W came up with to help make adjustments based on the BLM history table. I've so far been able to smooth out the running quite a bit, but one problem I'm running into is the desired idle is running high as does the idle itself. I've been going up and down the tables to try and figure out what is gonna cause it to have a high calculated desired idle. Keep in mind the engine was warm ~200F and I had just driven around. I looked through the idle speed tables and they seem okay so I'm just not sure.

Is there anyway to go about finding where it goes after the Idle speed tables to the final desired idle speed? I see the Integral and propotional tables as well, but despite just finishing a class on Dynamic controls I really don't know what I'm doing in that aspect. I just want to see what it might be reading that has it calculate a high rpm idle.

[don3194]

Figured I should post the Log, Bin, and the definition files if anyone wanted them.

[dave w]

Often the Throttle Body minimum air setting requires adjusting for the correct IAC steps at engine idle. Often engine idle IAC steps between 10 ~ 40 are acceptable.

The attached has some helpful information on setting minimum air.

[don3194]

Thanks, I will take a look later this week. Darn school has me too busy this week.

Another question, and possibly for another thread, the datastream definition file used there has a gauge for WBO2 sensor. I dont have a WBO2 setup so is it ok for it to be showing full tilt on 10:1? Is there any way to show what AFR the Narrowband is reading? I will consider getting a WBO2 in the future but I do not have one right now.

[don3194]

Often the Throttle Body minimum air setting requires adjusting for the correct IAC steps at engine idle. Often engine idle IAC steps between 10 ~ 40 are acceptable.


The attached has some helpful information on setting minimum air.

I was playing around with the instructions in the PDF you sent but I couldnt seem to get the IAC to respond. I'm really not sure whats going on here, I check the wiring from the IAC to the PCM and it got a good connection and its all wired correctly, as far as I know. I was playing around and only one time it drove the pintle out, but it just simply wont continue to respond. It stuck all the way in(no airflow) now, but the ECU still says its IAC counts are at 150 and I dont know how to reset it. I also tried two other spare valves I have, and neither provided different results.

[don3194]

I was playing around with the instructions in the PDF you sent but I couldnt seem to get the IAC to respond. I'm really not sure whats going on here, I check the wiring from the IAC to the PCM and it got a good connection and its all wired correctly, as far as I know. I was playing around and only one time it drove the pintle out, but it just simply wont continue to respond. It stuck all the way in(no airflow) now, but the ECU still says its IAC counts are at 150 and I dont know how to reset it. I also tried two other spare valves I have, and neither provided different results.

UGHH Okay, So I swapped valves again and it magically started working?
I followed the instructions in the PDF again but I can't seem to get the pintle to drive out when connecting pins A and B on the ALDL connector. I think it drives it out some but there is still air getting sucked in from that spot, not enough to hear normally but I can feel it and hear it if I stick my finger down in there. I tried continuing with the rest of the instructions but I still have the same high desired idle issue.

[dave w]

Often the TPS voltage shown by TunerPro RT is slightly different than the TPS voltage measured with a voltmeter.

Adjusting the minimum air screw will change the TPS voltage.

As a baseline starting point, the minimum air screw is adjusted until a strip of paper has a slight drag on the clearance between the throttle blade and throttle bore. The next baseline step is to adjust the TPS voltage to 0.55 volts using a voltmeter. The final baseline step is to jump ALDL pins A & B with the ignition on key on / engine off for 60 seconds.

The minimum air adjustment requires the engine be warmed up to full operating temperature.

[don3194]

Often the TPS voltage shown by TunerPro RT is slightly different than the TPS voltage measured with a voltmeter.

Adjusting the minimum air screw will change the TPS voltage.

As a baseline starting point, the minimum air screw is adjusted until a strip of paper has a slight drag on the clearance between the throttle blade and throttle bore. The next baseline step is to adjust the TPS voltage to 0.55 volts using a voltmeter. The final baseline step is to jump ALDL pins A & B with the ignition on key on / engine off for 60 seconds.

The minimum air adjustment requires the engine be warmed up to full operating temperature.

I'm gonna take this as a lesson to not touch if you don't know. I had enabled the A/C high pressure switch setting in the BIN because I have one wired into the system from the factory, however it does not send signal to the ECU, from what I can tell. Rather, I believe it is in part of the circuit to send power through the HVAC switch to the A/C clutch.
I had noticed it was locked on 1000 rpm in park/neutral and 1125 in drive and sure enough I found that correlated to the A/C high pressure rpm constants.

I will go back and tune the minimum air screw to my setup, but I am glad I figured out why it was commanding high idle.