Cartrax

Been wrestling with cold idle stalling and it's getting worse now with the cooler weather. Appears IACs are not opening enough for some reason. IAC's are new and MAP and TPS are functioning properly. No Malf codes noted (EBL ECM). Could be CTS -??? CTS readings on WUD indicate a functioning sensor - but I'm not sure which CTS feeds the WUD. Is it the one that feeds the ECM? If no how do you test it?

T.L.

'84s didn't have Xfire...unless it's a Corvette...

Twin_Turbo

iTrader: (25)

The one under the thermostat. If its the mushroom type replace it for a tpi weatherpack type w pigtail. The mushroom type are motorious for corroded connection resulting in rich running.

Cartrax

Hmmmm....

Cartrax

Thanks. That's the one that drives the ECM. It's the newer configuration and as a result of the readings seems to be functioning correctly. Folks telling me I simply need to get more air in at cold idle and re-balance TB's. Going to give that a shot. I didn't think that was the issue since it once ran better. Have changed injectors though I never touched the throttle plate adjustments...

RBob

iTrader: (1)

The CTS is the one with two wires, a YEL and a BLK. It goes to the ECM, which then reports the value to the WUD.

If the IAC needs to be open further on cold start there is a table to adjust this. This table is used to set the IAC(s) to the cranking/start position (based on CTS):

IAC - Powerup Init Steps

:Once running the ECM uses the following table to set an initial IAC position as the engine warms up and the car is being driven:

IAC - Minimum Idle Steps

Again based on CTS. Adjust the required table dependent upon when the engine is stalling.

RBob.

Cartrax

Thanks. Will try that before I start playing with throttle plates.

Cartrax

Short follow-up - After jacking IAC tables with no success I opened throttle plates a bit more and that worked. No clue why the plates required adjusting since I never touched the setting.