Idle surge
- Thread starter JoniNitro
- Start date
R.J.
Member
If you do end up having idle issues try resetting your idle like this:
'94-'95
Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.
The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.
Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.
Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.
Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.
If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC. You are done.
'94-'95
Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.
The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.
Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.
Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.
Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.
If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC. You are done.
I agree with Grady, though I dont have experience tuning a cobra.
Seems to me in about all cases (about any stang) that it's hit or miss. Just gotta give it a shot and tweak as necessary...........
Good luck.
Seems to me in about all cases (about any stang) that it's hit or miss. Just gotta give it a shot and tweak as necessary...........
Good luck.
CManT1914
New Member
Your idle surge may have come from the maf getting during the cai install. 
I doubt those mods will give you any issues (not serious ones anyway).
I doubt those mods will give you any issues (not serious ones anyway).
The bleed screw. On the front of the IAC is a rubber plug. Remove it and you will see a screw in there (mine has a hex head). You can turn that in or out to adjust the idle (though I dont like adjusting the idle with that screw, since it will cause a hanging idle if you open it too far).Guero said:
Guero said:
Like JT said, its under the little white rubber plug and its an allen head screw.
Closed all the way ain't right
I've seen em give a pretty good isc duty cycle within a range of 1 to 2.5 turns out.
It depends on how far you got the tb blade stop screw backed out and different stuff from your combo can make a diff as well.
Grady
R.J.
Member
BBK's is a flat head screw. Do you have a BBK? If your screw was all the way down, you definatly should do the above mentioned procedure. A friend of mine did a TFS package with a BBK 75 mm and it wouldn't idle for anything. Setting his idle this way was the only thing that could fix it and gave him a great idle. Being as far out as you are, you will also have to pay attention to TPS voltage when making these adjustments.
You need a volt meter and two paper clips. With the TPS connector still connected, bend the paper clips into "L's" and stick them into the back of the TPS connector. One in the top wire (ground) and one in the middle wire (sig). Now connect the volt meter to the clips and while making your stop screw adjustments, with the car running, check for .99 volts.
If you can't get your idle where you want it and show .99 volts, then get the idle correct and set the TPS by the sensor. good luck
You need a volt meter and two paper clips. With the TPS connector still connected, bend the paper clips into "L's" and stick them into the back of the TPS connector. One in the top wire (ground) and one in the middle wire (sig). Now connect the volt meter to the clips and while making your stop screw adjustments, with the car running, check for .99 volts.
If you can't get your idle where you want it and show .99 volts, then get the idle correct and set the TPS by the sensor. good luck
The fender kits from MAC/BBK/Ebay that have a bend in front of the meter is not the best for our cars. They've been known to cause idle issues. Refer to the above posts for getting most of the issues straight. If it still persists may want to just bolt an air filter the meter and ditch the bendy part.
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