Fluctuating Idle
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
At one time I created this for you.
http://www.scotthansen.net/cshumansburn.bin Right click and save target as.
If you run this file, and datalog with Datamaster I will tune this for you.
http://www.ttspowersystems.com/DataM...ownloads2.html
As I've said before, you can make small incremental changes to your throttleblade screw and observe IAC counts at a fully warmed idle. Set the IAC to between 40 and 60. setting the TPS is not required on an SD car.
http://www.scotthansen.net/cshumansburn.bin Right click and save target as.
If you run this file, and datalog with Datamaster I will tune this for you.
http://www.ttspowersystems.com/DataM...ownloads2.html
As I've said before, you can make small incremental changes to your throttleblade screw and observe IAC counts at a fully warmed idle. Set the IAC to between 40 and 60. setting the TPS is not required on an SD car.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Sometimes this happens if you are running rich. When the O2 sensor gets hot enough to start working the ECM goes into closed loop mode and opens the IAC to compensate for the rich mixture. That causes the idle to go up so the ECM closes the IAC to lower the idle. Then the mixture goes rich and the cycle starts over again.
Burning Brakes
Joined: Mar 2010
Posts: 1,094
Likes: 68
From: Providence RI
FWIW...
My car always hunted a little bit for an idle. I blamed it on a worn out/sticky throttle body. Recently, the car ran like crap at 1/4 throttle. Punch it, it screwed. Lug along on the side roads, it was pissed.
Tested my TPS and it was .3 volts idle, 2 volts WOT. Ohm'd it out, 1300 closed, 4000 wide open. They're supposed to ohm out 1000-8000. Changed the TPS because of the hesitation issue and my idle issues cleared up. Car always ran fine but I am thinking the TPS was iffy all along. Just test it on/off car and look at the values in datamaster.
If i remember right, you have a 91, just like me with the super ram too. Stock TPS setting doesn't matter as much because they aren't adjsutable. The car uses the initial value as a baseline for idle and determines a range after that. If the car starts up and the TPS is measuring .4 volts, but then it runs, gets hot, and is showing .5 volts with the throttle closed, the car thinks that the throttle is still open, etc.
Just an idea...worth a shot.
Mike
My car always hunted a little bit for an idle. I blamed it on a worn out/sticky throttle body. Recently, the car ran like crap at 1/4 throttle. Punch it, it screwed. Lug along on the side roads, it was pissed.
Tested my TPS and it was .3 volts idle, 2 volts WOT. Ohm'd it out, 1300 closed, 4000 wide open. They're supposed to ohm out 1000-8000. Changed the TPS because of the hesitation issue and my idle issues cleared up. Car always ran fine but I am thinking the TPS was iffy all along. Just test it on/off car and look at the values in datamaster.
If i remember right, you have a 91, just like me with the super ram too. Stock TPS setting doesn't matter as much because they aren't adjsutable. The car uses the initial value as a baseline for idle and determines a range after that. If the car starts up and the TPS is measuring .4 volts, but then it runs, gets hot, and is showing .5 volts with the throttle closed, the car thinks that the throttle is still open, etc.
Just an idea...worth a shot.
Mike
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
FWIW...
My car always hunted a little bit for an idle. I blamed it on a worn out/sticky throttle body. Recently, the car ran like crap at 1/4 throttle. Punch it, it screwed. Lug along on the side roads, it was pissed.
Tested my TPS and it was .3 volts idle, 2 volts WOT. Ohm'd it out, 1300 closed, 4000 wide open. They're supposed to ohm out 1000-8000. Changed the TPS because of the hesitation issue and my idle issues cleared up. Car always ran fine but I am thinking the TPS was iffy all along. Just test it on/off car and look at the values in datamaster.
If i remember right, you have a 91, just like me with the super ram too. Stock TPS setting doesn't matter as much because they aren't adjsutable. The car uses the initial value as a baseline for idle and determines a range after that. If the car starts up and the TPS is measuring .4 volts, but then it runs, gets hot, and is showing .5 volts with the throttle closed, the car thinks that the throttle is still open, etc.
Just an idea...worth a shot.
Mike
My car always hunted a little bit for an idle. I blamed it on a worn out/sticky throttle body. Recently, the car ran like crap at 1/4 throttle. Punch it, it screwed. Lug along on the side roads, it was pissed.
Tested my TPS and it was .3 volts idle, 2 volts WOT. Ohm'd it out, 1300 closed, 4000 wide open. They're supposed to ohm out 1000-8000. Changed the TPS because of the hesitation issue and my idle issues cleared up. Car always ran fine but I am thinking the TPS was iffy all along. Just test it on/off car and look at the values in datamaster.
If i remember right, you have a 91, just like me with the super ram too. Stock TPS setting doesn't matter as much because they aren't adjsutable. The car uses the initial value as a baseline for idle and determines a range after that. If the car starts up and the TPS is measuring .4 volts, but then it runs, gets hot, and is showing .5 volts with the throttle closed, the car thinks that the throttle is still open, etc.
Just an idea...worth a shot.
Mike
Thanks, I'll look at that.
