Idle routines not kicking in everytime. HELP!!!
03-23-2009, 01:58 PM
#1
Idle routines not kicking in everytime. HELP!!! HELP!!!!!! Using HP Tuners.
I am tuning an 8 sec street car here. Yes, my favorite. Anyway, I also have this problem with my car so I gathered some data so that you guys can see what I am talking about.
This log is of the car just sitting at idle in gear. You will see that the idle routines are working fine in the begining of the log. The car is in gear with my foot on the brake pedal. At the one minute mark, I engage the transbrake and give it a little gas (you can see the TPS% increase). Once I let out of the gas, TPS% goes back to zero. Idle routines kick back in (you can see the timing bounce around and the IAC counts go to zero or so). Rinse and repeat. The next time that I do it, the timing and IAC hang (main spark table and IAC steps vs effective area table values are displaying on the scanner).
I see that the TPS% is stuck at 1% but I have the Min TPS (under Main Spark Advance) set at 2% and have tried going up to 5% without any results. PLEASE PLEASE PLEASE help me resolve this issue!!!!! When the idle routines are working this thing idles absolutely perfect at 1000 RPM's.
LS1tech wont allow me to upload the config file but none of the custom values should be required in order to see what I am talking about.
I am tuning an 8 sec street car here. Yes, my favorite. Anyway, I also have this problem with my car so I gathered some data so that you guys can see what I am talking about.
This log is of the car just sitting at idle in gear. You will see that the idle routines are working fine in the begining of the log. The car is in gear with my foot on the brake pedal. At the one minute mark, I engage the transbrake and give it a little gas (you can see the TPS% increase). Once I let out of the gas, TPS% goes back to zero. Idle routines kick back in (you can see the timing bounce around and the IAC counts go to zero or so). Rinse and repeat. The next time that I do it, the timing and IAC hang (main spark table and IAC steps vs effective area table values are displaying on the scanner).
I see that the TPS% is stuck at 1% but I have the Min TPS (under Main Spark Advance) set at 2% and have tried going up to 5% without any results. PLEASE PLEASE PLEASE help me resolve this issue!!!!! When the idle routines are working this thing idles absolutely perfect at 1000 RPM's.
LS1tech wont allow me to upload the config file but none of the custom values should be required in order to see what I am talking about.
03-23-2009, 02:13 PM
#3
I replied over there LOL. Here's a copy.
There is no set screw in the blade so I can't get it anymore closed. I also have a return spring on it and manually pushing it closed does not cure the problem. I will log the TPS voltage to see what that says. Until I can resolve this issue, I can't address the idle airflow as the LTIT and STIT are disabled once the problem starts. If my idle routines were working and the IAC closed completely everytime, I'd be in good shape. My problem is getting the damn thing to close and getting the over and underspeed spark tables to kick in. Thanks for the help and I will check the voltage on the TPS once the problem begins.
There is no set screw in the blade so I can't get it anymore closed. I also have a return spring on it and manually pushing it closed does not cure the problem. I will log the TPS voltage to see what that says. Until I can resolve this issue, I can't address the idle airflow as the LTIT and STIT are disabled once the problem starts. If my idle routines were working and the IAC closed completely everytime, I'd be in good shape. My problem is getting the damn thing to close and getting the over and underspeed spark tables to kick in. Thanks for the help and I will check the voltage on the TPS once the problem begins.
03-23-2009, 02:52 PM
#4
Here's another log with TPS voltage (just add it to the supplied config file). I find that after I flash the PCM, even with the same exact tune, the idle routines always work until I crack the throttle. Sometimes they work again and sometimes they dont. Anyways, the TPS voltage shows .27v @ 0% TPS in the begining of the log and everything appears to be working correctly. I give it gas, voltage starts jumping between .25-.27 and 0-1% TPS and then it doesn't work anymore. It's like I am crossing a threashold but then I can't get back everytime.
03-23-2009, 03:21 PM
#5
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If you check for codes, do you see any "immature"
TPS etc.? I'm not used to seeing TPS voltage that
low, I do not know if there's a lower limit to TPS
that might trigger a fault mode. High will just make
it not think it's at idle, but overly low might act
differently.
Any flakiness in ECT readings that might make it
fall out of closed loop idle for temperature?
TPS etc.? I'm not used to seeing TPS voltage that
low, I do not know if there's a lower limit to TPS
that might trigger a fault mode. High will just make
it not think it's at idle, but overly low might act
differently.
Any flakiness in ECT readings that might make it
fall out of closed loop idle for temperature?
03-23-2009, 03:36 PM
#6
If you check for codes, do you see any "immature"
TPS etc.? I'm not used to seeing TPS voltage that
low, I do not know if there's a lower limit to TPS
that might trigger a fault mode. High will just make
it not think it's at idle, but overly low might act
differently.
Any flakiness in ECT readings that might make it
fall out of closed loop idle for temperature?
TPS etc.? I'm not used to seeing TPS voltage that
low, I do not know if there's a lower limit to TPS
that might trigger a fault mode. High will just make
it not think it's at idle, but overly low might act
differently.
Any flakiness in ECT readings that might make it
fall out of closed loop idle for temperature?
03-23-2009, 08:03 PM
#7
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I meant closed loop idle RPM control, not closed
loop fueling. It will not do anything but airflow-
calculation-based IAC positioning until closed loop
idle is enabled, then you get active LTIT/STIT and
adaptive spark.
loop fueling. It will not do anything but airflow-
calculation-based IAC positioning until closed loop
idle is enabled, then you get active LTIT/STIT and
adaptive spark.
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03-24-2009, 12:47 PM
#8
OK, I put a new TPS sensor on the car. Start the car and idle routines are good and all is well. 0% TPS is being reported at .47v. Give it gas once or twice (in park) and then let off and the TPS voltage goes down to .41-.43 and the TPS% jumps between 0-1% and no idle routines. For ***** and giggles, I pulled the plug from the TPS sensor and it settled right down. Idle routines kicked right in. That drops voltage to 0.00v as well as a solid 0% throttle position. Unfortunately, when you plug it back in, voltage goes back to .47 but throttle position goes up to 11-13% and the idle rpm really runs away. Guys, I can't be the only one that has had this problem. Any tricks that you guys might suggest. At this point, if I have to wire in a relay and a momentary micro switch on the pedal, the owner is willing to do whatever. Damn street driven race cars!
03-24-2009, 02:23 PM
#10
Yeah. We did that yesterday. The problem is that the initial voltage (while the idle routines are running) is higher than when the percentage starts to jump around. For example: Initial start-up TPS voltage is .47 and reads 0% throttle position. Then once you get on it a bit, voltage DROPS to .45v but throttle position jumps back and forth between 0-1%. What is really stumping me is that I have the main spark tables set to disable at 2% throttle position yet they are not disabling regardless. I even raised it to 4%. Makes no difference.
03-24-2009, 06:55 PM
#16
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I worked on this same problem a year ago. Before I found out what to change, the throttle started reading 0 all the time and things started working. I think there is software that adapts over time. It was a pain, then it got better over time. Sorry to be no help.
03-24-2009, 07:52 PM
#17
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I assume your battery is in the trunk based on your car. But we had 1 car do something similar & it was a corroded battery cable (more typical for stock location & wiring) but it might be something to check? 
03-25-2009, 07:07 AM
#18
I missed this post. I'm not really sure what you are talking about here. Where is this located? I have modifed the IAC position vs effective area so that the IAC is much more closed than normal. This is currently masking the problem as the car will only idle 100-200 rpm high when the idle routines dont kick in.
03-25-2009, 07:12 AM
#19
03-25-2009, 11:37 AM
#20
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I wonder if there is a problem relating to the VSS
being missing, there is a MPH enable and hysteresis
for idle but maybe with the VSS faulted, you can't
get back to idle because there is no MPH<value
decision to be made? Like, you may start in an
idle condition but once out, with missing sensor,
can't get back?
being missing, there is a MPH enable and hysteresis
for idle but maybe with the VSS faulted, you can't
get back to idle because there is no MPH<value
decision to be made? Like, you may start in an
idle condition but once out, with missing sensor,
can't get back?