RomRaider

I have identified a number of maps I believe are used for idle control and would like to kick of a conversation. I do not have a thorough understanding of it at this point, but have at least anecdotal evidence that some of these maps can help adjust how the car idles.

A2ZJ710J (2004 USDM STI 2.5L DBW)

0x53ACC (3D)
0x53AE8 (3D)
I think this is the starting point for DBW idle throttle angle, some sort of initial angle map that is used before the timing and throttle angle control loops kick in.

0x53BC8 (2D)
Not sure, but it seems like the value affects throttle angle. Maybe a multiplier for some other factor. Haven't messed with this much.

0x57D4C (1D)
I think this is a "desired torque" number before the idle control gives control of throttle angle over to pedal input. Default 30. I've noticed sometimes throttle angle will actually go DOWN when you start to touch the throttle. Adjusting this up can help. Too much and it makes the pedal numb, then it suddenly surges open.

0x54DA8 (2D)
Idle timing when > 2 kph?
0x5E26C (1D)
Idle timing when < 2 kph?

0x55120 (3D)
0x5513C (3D)
I think this is the idle timing proportional or integral factor for closed loop idle timing control. Column header RPM error, row is RPM.

I haven't messed with idle stuff much, but it definitely an area that needs some attention in the future as far as tuning with RomRaider. Right now, I'm out of analysis stage for the next ecu/logger defs and doing the grunt work - looking up all the offsets for new tables/parameters for the 190 existing rom revisions (very time consuming). So I can't add anything to the discussion right now, but I'm curious as to what you come up with.

Any chance that these tables could be added to Romraider on the next rev? Anyone with higher duration, higher lift cams could benefit from idle ignition advance tables.

The next ecu def's new tables are already set in stone as I am in the middle working on them already. Further analysis would be needed anyway which is the point of this thread - to start a discussion about idle-related logic.

Can the relevant code be captured in one of those flowchart images from IDA?
Or would it require an array of 30" monitors to see it all?

Freon,

Thanks for working with me on this! I am interested in testing the idle controls out with my cams. I think I can fix the idle hunt due to cams and ported heads if I change the idle timing. I also had to disable my misfire codes because I was tired of being without cruise. The misfire cel's would come on during idle, cold start up or warm.

Here is my map. I have a very similar setup to you but I do use the utec to tune wot fueling and ignition. I have a gt30r on a built shortblock with diy handported heads and cosworth cams. I am catless with perrin headers and ebay fmic and diy 3" intake. My build info is in nasioc built motor discussion with thread title "my gt30r build in progress" if you want more info. anyway, i am intersted in testing this out.

I guess I will be logging total timing to check which table the ecu is referencing during idle.?

I havent looked at 32 bit idle control much, since its rarely an issue, but a while back Bill was able to get me a test def for idle timing control on A4SGE01C, and it does do the trick with TGV deletes, light flywheel/pulley, and cams. On the 16 bit ECU, it uses a base timing target which never changes. Stock is 12 degrees. The "short term" immediate correction that keeps idle in check is timing control. The ECU adds +- 8 degrees based on idle speed error to keep on track. More timing if idle = less than target speed. The "long term" or learnerd correction is the idle speed motor. I'm not totally sure what the relation is, but IAC duty is slow reacting and a learned value based either on timing or idle speed correction.

These are my observations based solely on logging and intuition, I have no idea how to check out the code to verify lol.

I've found that reducing the base idle timing prevents stalling with light rotating components, but causes some drivability issues because of the drastic timing jump into the map, but after some rescaling of the initial off idle timing load zones, it proved to be a very useful tuning tool.

Thats my 2 cents..

Thanks for the info. I have tvg deletes, lightended flywheel, and cams as well. I think this will be the ticket.

Ok, here's what I'd like you to do:

Start with a hot engine. Load each map in order and repeat the following steps:
1. Center your steering (yes, I'm serious and you NEED to do this). Flash the map.
2. Start the logger and start log the following (just use the standard SSM items):
Throttle Opening Angle
Accelerator Opening Angle
Engine Speed
AFR Correction #1
AFR Learning #1
AFR Front O2 sensor (AFR or lambda)
Ignition timing (total/final)
Coolant temp
Intake air temp
Mass airflow g/s
3. Start the car and let it idle for 120 seconds. Do not touch anything.
4. While still idling, poke the throttle very lightly and as briefly as you can then let off. Just enough to bump you up to 1600-1800 rpm. Do not touch the throttle otherwise. Let idle it idle for 15-20 seconds. Poke the throttle again. This should not take longer than 2 minutes. I only need 3 - 4 stabs about 15-20 seconds apart.
4. Take a quick drive, around the block at 20mph is fine. I don't really care about watching the car cruise, this is for other purposes. There is no need to drive more than 3 minutes and get up to 20mph or so briefly.
5. Come back to rest. Let it idle for one minute.
6. Poke the throttle again per above instructions.
7. Shut down, stop the log. Label the log with the ROM number.
8. Turn the car off. Go back to step #1 with the next ROM.

And obviously post all the logs here when you're done. Please do all of the ROMs at the same time. It shouldn't take long (15-20 minutes max). Please try to take these steps as literally as possible. Even small stuff like the steering column can have an effect. Do not idle longer than requested. Please also do not attempt to figure out what each ROM does. Just follow the tests. It is better if you are ignorant as to what I've changed. Nonetheless, there is nothing that should cause and big problems other than bad idle. I'm not messing with anything that I haven't done on my own car already.

Here are the test ROMs:
http://freon.shackspace.com/car/ecu%20a ... er-001.hex
http://freon.shackspace.com/car/ecu%20a ... er-002.hex
http://freon.shackspace.com/car/ecu%20a ... er-003.hex
http://freon.shackspace.com/car/ecu%20a ... er-004.hex

Here are the logs for each hex file.

I have a 16bit ECU (A4TF520F) and need access to idle control. These camshafts with higher lift/duration simply don't idle well with stock idle control. The timing goes anywhere from 1 degree to 20 degrees trying to adjust engine speed. The IACV ranges anywhere from 30% to 50%.

The issues only occur when returning to idle.

It would be nice to adjust ignition timing at idle for higher duration cams. This should help combat the low intake manfiold vacuum at idle.

jon, it's "technically" a hack, but look for a compensation table like ECT over idle timing and adjust it that way. that's how i adjusted mine.

the idle map is at most a 2x2 3d matrix iirc anyway. most adjustments will be global anyway.

You should be able to adjust idle timing using the Timing Compensation Idle A + B.

I'd like to bump this thread up based on an idle control issue us boost-less masses are having when upgrading cams...

topic4646.html

Some more work into this area would be hugely appreciated.