Adjusting Idle and Diagnostic Wire - Toyota Nation Forum : Toyota Car and Truck Forums

chicagoguy · 03-07-2005, 07:40 PM

Howdy Folks,

I have a 1991 Celica with a 4A-FE engine. I need to adjust the idle and I have a set of Toyota Factory Service Manuals with instructions for the adjustment.

In the manual it says to jump the Diagnostic Wire from E1 to TE1 of the Check Connector. The Diagnostic Wire has a Toyota Part Number of 09843-18020. In the manual, the wire looks like two wires about six inches long tied together on one end and have terminals on the two free ends.

I went to a Toyota dealer and they don't have the Diagnostic Wire and gave me a number to call to order one. It takes 5 days to get it and I need to set the idle now.

Do you know if the Diagnostic Wire is just a regular wire with terminals attached or is it some sort of special wire with a resistor or some other component inside the point where the two wires are tied together?

Thanks for your input.

lcarocha · 03-07-2005, 08:23 PM

Just use any piece of wire you have handy.... even a paper clip will do.

fredk · 03-07-2005, 10:19 PM

clean up the throttle body before you do anything

chicagoguy · 03-08-2005, 12:44 AM

Thanks guys, I appreciate your help.

chicagoguy · 03-13-2005, 01:43 AM

Hi again folks,

I adjusted the idle according to the manual at 800 RPM and drove her around a while afterwards.

The idle stayed at 800 RPM for about ten minutes but then went to 1200 RPM. After driving around a little while more, it stayed at 1200 RPM.

What the heck can I do now? Is there a way to reset everything and start over?

Also in the manual, it said to get to normal operating temp and then race the engine at 2500 RPM for two minutes and then put then jumper wire in the check connector before setting the idle.

What's the pupose of racing the engine at 2500 RPM if you are already at normal operating temperature?

Many Thanks for you input.