My car has recently started too idle really high, about 1200 rpm, when in park. It does not happen every time but probably 9 out of 10 times. It drops down too about 750-800 rpm when put in reverse or drive. The IAC reads 0 on the scanmaster and if you give it a little gas it goes up too around 30 and then starts dropping back down until it gets too 0. I have replaced the IAC and the same thing is occuring. What else could be causing this?
High idle when in park
- Thread starter sams86gn
- Start date
If you're IAC counts are at zero, that means the ECM cannot control the idle via the IAC valve any longer. The plunger on the IAC valve is fully extended and blocking off the air passages. As such, you're idle air screw is probably turned in CW too much holding the throttle plate open in the rest position. Turn the idle air screw CCW about 1/2 turn at a time while readjusting the TPS sensor to keep it within spec. Let the car settle for about 30 seconds to a minute and repeat the process until you see your numbers climb above zero while in Park. Numbers will jump higher in gear. Turn car off and restart it. Done.
Ok this is going too be a dumb question but which one is the idle air screw? I know it's drivers side of throttle body on throttle linkage but I do not see it. Anyone have a picture? Also as I was reading on this it was said that it needs too be in closed loop. Does this really matter?
- Joined
- Jan 21, 2007
TRY resetting it...
- Warm the engine to full operating temps
- Turn engine off and then turn the key back to ON
- With the IAC connected, jumper pins A and B at the ALDL.
- Wait 30 seconds and unplug the IAC
- Remove the jumper at the ALDL
- Start the engine
- Adjust engine RPM to 500-550 in Drive using the throttle stop screw on the throttle body.
- Shut the engine off and plug the IAC back in.
- Restart the engine
- Set TPS to .40-.44 volt or whatever your chip manufacturer specifies
Bruce Urie
The Ventures,CCR forever!
- Joined
- Dec 30, 2006
DO THIS:
Bruce '87 Grand National
Bruce '87 Grand National
Bruce Urie
The Ventures,CCR forever!
- Joined
- Dec 30, 2006
Uh, you might have to REPLACE it, as this here being a .44 magnum, the most powerful handgun in the world and can blow your IAC CLEAN OFF, you have to ask yourself a question.....do you feel like replacing it? WELL, DO YA, SPORT? But if you used a BB gun, that might lessen the option of replacing about $450 worth of parts.
(or more) My repair methods are very, very, very expensive for some reason.........don't know why.
Bruce '87 Grand National
(or more) My repair methods are very, very, very expensive for some reason.........don't know why.Bruce '87 Grand National
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The idle air screw is that little screw with the spring on it that is bottomed out against the throttle stop in this photo you took of the transmission tv cable. There should only be 1 to 1-1/2 threads coming through the throttle stop on the throttle body.
Glad you got it fixed.
Now put some plastic wire cable ties on the vacuum line / rubber adapter going to the fuel press. regulator so it doesn't blow off under boost. Also a good idea to do all the vacuum lines and hoses as well with the cable ties.
Now put some plastic wire cable ties on the vacuum line / rubber adapter going to the fuel press. regulator so it doesn't blow off under boost. Also a good idea to do all the vacuum lines and hoses as well with the cable ties.
Look at the top of the intake manifold in front under the throttle linkage and there should be a switch screwed in the intake manifold with a one prong wire connector if i remember correctly that is where the green wire goes. I did away with that a long time ago thats why i'm not exactly sure,but i'm pretty sure that is where it goes.
Here is a link for some info for you. There is a lot of good info on that site even on how to reset the transmission TV cable if you need that.
http://www.gnttype.org/maint/sensors.html
Dave Dunbar
Member
- Joined
- Sep 10, 2012
Fuel pump jumper wire.
