Adaptive Idle isn't happening. Any ideas?
01-06-2009, 07:18 AM
#1
Adaptive Idle isn't happening. Any ideas? I swapped to the new Fiber Tuned intake from Nitrous Outlet and once I fired her up, my idle was noticeably higher. I checked for leaks and even removed it again this weekend to double check but nothing. So I started doing some logging with HPTuners and noticed that the IAC wasn't moving at idle and neither was my timing. Since I am idling high by 200 RPM's or so, I figured that the IAC should be closing and I should be pulling some timing in order to get my RPMs down with the overspeed corrections in the tune.
Here's what happens:
I turn on the car and it idles high for about 1.5 seconds which is exactly what the Adaptive Idle start-up delay is set at.
After that, adaptive idle kicks in and you can see the Idle Air Controller steps coming down (closing) and the timing retards to get the idle down (within about 100 RPMs of desired) in park (no load).
Put it in drive with the foot on the brake and the RPM's come down to 950 RPM and you can see the IAC and the timing moving around to get me a nice steady idle.
I take off and that's it. When I come to the next stop, idle is back up to 1100-1150 RPM or so. Timing doesn't move and the IAC is stuck at it's last position.
Getting pretty frustrated here with this thing and would appreciate any ideas.
Some of the challenges and details as they pertain to the tuning:
98 PCM with a 2Bar Custom OS and the car is tuned in OLSD.
The car is NA and I only put in this OS in order to get rid of the secondary VE table.
IAT sensor has a resistor that reads 70* all the time.
There is no speedo signal to the PCM.
The car has a TH350 swapped in and was previously an M6. PCM has no idea what gear I am in which is why I have to deal with a slightly higher idle in Park/Nuetral.
TPS is sometimes only coming down to 1% and not zeroing out. Regardless of whether it reads 0 or not, voltage is at .33V when I am off the pedal. I've reset the TPS several times and the blade is definitely closing completely so it isn't a worn return spring.
That's about it I think.
Here's the tune.
Here's what happens:
I turn on the car and it idles high for about 1.5 seconds which is exactly what the Adaptive Idle start-up delay is set at.
After that, adaptive idle kicks in and you can see the Idle Air Controller steps coming down (closing) and the timing retards to get the idle down (within about 100 RPMs of desired) in park (no load).
Put it in drive with the foot on the brake and the RPM's come down to 950 RPM and you can see the IAC and the timing moving around to get me a nice steady idle.
I take off and that's it. When I come to the next stop, idle is back up to 1100-1150 RPM or so. Timing doesn't move and the IAC is stuck at it's last position.
Getting pretty frustrated here with this thing and would appreciate any ideas.
Some of the challenges and details as they pertain to the tuning:
98 PCM with a 2Bar Custom OS and the car is tuned in OLSD.
The car is NA and I only put in this OS in order to get rid of the secondary VE table.
IAT sensor has a resistor that reads 70* all the time.
There is no speedo signal to the PCM.
The car has a TH350 swapped in and was previously an M6. PCM has no idea what gear I am in which is why I have to deal with a slightly higher idle in Park/Nuetral.
TPS is sometimes only coming down to 1% and not zeroing out. Regardless of whether it reads 0 or not, voltage is at .33V when I am off the pedal. I've reset the TPS several times and the blade is definitely closing completely so it isn't a worn return spring.
That's about it I think.
Here's the tune.
01-06-2009, 09:33 AM
#2
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I'm thinking this is throttle cracker / follower
engaging based on first TPS > 2%, but can't
disengage without the VSS signal to make the
< 1 MPH determination. So you're bumped by
the airflow adder value and not looking at an
idle strategy anymore.
engaging based on first TPS > 2%, but can't
disengage without the VSS signal to make the
< 1 MPH determination. So you're bumped by
the airflow adder value and not looking at an
idle strategy anymore.
01-06-2009, 02:10 PM
#4
This is kind of along the lines of what I was thinking. The response that I got on the HPTuners site was to try a stock table for the throttle follower decay values. I'm going to try that first and if that doesn't work, I guess that I will have to maybe tie in one of the front ABS wheel speed sensors that I am not currently using in order to give the PCM those values. The problem is that I have a buddy that I think we are having the same issue on his car and the wheel speed sensor option is not available to him as he has the lightwieght Strange brakes all the way around.
01-06-2009, 03:25 PM
#5
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On old school add-on cruise controls, they used
to have a bolt-on pickup and glue magnets on the
driveshaft to blip it. Maybe something like this,
and figure the pulses per revolution out to pulses
per mile for the PCM, could get you a good-enough
VSS.
to have a bolt-on pickup and glue magnets on the
driveshaft to blip it. Maybe something like this,
and figure the pulses per revolution out to pulses
per mile for the PCM, could get you a good-enough
VSS.
01-06-2009, 05:41 PM
#7
This is kind of along the lines of what I was thinking. The response that I got on the HPTuners site was to try a stock table for the throttle follower decay values. I'm going to try that first and if that doesn't work, I guess that I will have to maybe tie in one of the front ABS wheel speed sensors that I am not currently using in order to give the PCM those values. The problem is that I have a buddy that I think we are having the same issue on his car and the wheel speed sensor option is not available to him as he has the lightwieght Strange brakes all the way around.
