Tune question
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
It mean you don't have a vacuum leak. or it's so small it's not effecting fuel control. You should be able to adjust throttle body to increase IAC counts. You do want to watch both IAC and TPS values as you do it.
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Race Director
Joined: Oct 2011
Posts: 16,089
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From: Dallas Texas
2025 C4 of the Year Finalist - Modified
I'll adjust it either today or tomorrow. Will report back. So adjust it with a warm engine. Dumb question, but do I turn it clockwise or counter clockwise? So try and get it around 20 counts, and TPS voltage a tad lower?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
don't go below .50 with TPS. turn screw counterclockwise 1/4 turn at a time. snap throttle then it idle stabilize. check readings. counter clockwise increase counts .clockwise reduces counts.
Safety Car
Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
Turn the screw counter clockwise to close the blades and that will raise your IAC count. Don't worry about the TPIS on a 1993 it is non adjustable and the computer uses the lowest voltage reading as 0% throttle.
Thread Starter
Race Director
Joined: Oct 2011
Posts: 16,089
Likes: 819
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Thank you kevova and bjankuski. Just had a thought. If my throttle blades are open too much, wouldn't my idle be too high? It is plus or minus 50 rpm of the desired idle rpm. Not saying you guys are wrong, just curious. If I were to close the throttle plates, wouldn't my RPM decrease, being too low?
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Thank you kevova and bjankuski. Just had a thought. If my throttle blades are open too much, wouldn't my idle be too high? It is plus or minus 50 rpm of the desired idle rpm. Not saying you guys are wrong, just curious. If I were to close the throttle plates, wouldn't my RPM decrease, being too low?
