ADJUSTING THE IDLE?????

[Tom and Vipers]

I have no idea if this applies to Viper but it was critical for an 88 Tbird turbo.

The IAC (Idle Air Control) bypases the throttle plates to allow the computer to control idle.

The computer will ask for about 1000 rpm on the turbo, however, you still need to adjust the mechanical idle just like an old car.

The trick is to set the mechanical idle just below the computer controlled idle. So when the computer is searching for idle, the engine cannot idle below the mechanical limit.

The way this is done is to pull the connector to the IAC and set the mechanical idle with a conventional idle adjustment screw.

Of course, I have no idea if this will work with Viper. Does Viper have and IAC or a machanical idle adj screw? I don't know yet.

Another problem with turbo 4 was the TPS sensor. (Throttle Position Sensor) This would get dirty/noisey and throw off computer idle control.

Hope this helps.

 

[99 R/T 10]

Hey Stve,
I had the same problem as you described, cold, no problem, but warm up to 190, stalls. For me, after staying at 190 for more than a few minutes or so, problem goes away. I disconnected the batt to reset the computer and at the same time charged the batt. Problem went away. Could say for sure if it was the batt being of low charge or the reseting of the computer, but for now all is well.

Mike

 

[Chuck Greggs S Arizona ACR]

Steve.....you may be reading the tach incorrectly. The first small mark after zero is 500rpm. The next larger one is 750rpm(which is mistaken for 500 by many folks). Idle should be around 704(plus or minus 25). If the idle is actually 400, it is not mechanically ajustable. The computer will try to compensate for any adjustments you make. Could be an idle air control motor problem. Good luck.

Chuck G.

 

[jgfurr]

I have this same problem, but it is not as pronounced as yours (doesn't happen every time I disengage the clutch). I've had the car at the dealer several times, and they could not pinpoint the problem. According to the computer they hooked up, my car idles properly. I've tried the following:

new plugs
new plug wires
disconnect the battery
new battery
re-synchronizing the throttle cables and then locking them
new intake manifold gasket

The last time I had the car in, the intake gasket was replaced at the same time I was having a new clutch and aluminum flywheel installed. It's definitely better now, but I can still watch the tach drop all the way down to 0 and then come back up. I don't know if the aluminum flywheel is helping the engine rev back up quicker because it doesn't actually stall now. However, I still see the problem by watching the tach.

I hope someone else has and idea of what we can try....