Check Engine Light Idle Changed

[WILDLIFE]

HELP I HAVE A 84. WHEN I START IT. IT HAS TO TURN OVER QUITE A FEW TIMES. BUT WHEN IT DOES START IT WILL IDLE REAL HIGH ABOUT 1800RPM THEN IT WILL SLOWLY IDLE BACK DOWN OVER ABOUT 2 TO 4 MIN THEN FLUCTUATE FROM 600 TO 900 ROUGHLY AT THAT POINT CHECK ENGINE LIGHT COMES ON AND STAYS ON. THIS ALL STARTED WHEN I NOTICED IT IDEL UP AND DOWN A FEW TIMES AT ABOUT A STEADY 35MPH. BUT IT WILL RUN PRETY SMOOTH ONCE IT IS WARM MOST OF THE TIME. WHAT SHOULD I CHECK FIRST? ALSO I READ A POST THAT SAID USE A PAPER CLIP FROM A TO B TO GET THE TROUBLE CODE IS THIS SAFE WITH ALL THE ELECTRONICS AND WILL IT WORK ON THE 84?
THANKS ALOT
GARY

 

[WILDLIFE]

JUST CHECKED THE CODE I READ IT AS CODE 12 THAT IS
BLINK PAUSE BLINK, BLINK.

 

[c4ever]

You should be pulling stored trouble code(s) after the 12 flashes three times. Make sure ign is in the on position but do not start car. Let us know what you get.
Carlo

 

[WILDLIFE]

I FIGURED THAT OUT ADOUT 5 MIN AFTER I POSTED OH WELL IT IS CODE 21 THROTTLE POSITION SENSOR IS THAT RIGHT? THE BOOK SAYS SCRIBE A POSITION MARK. I WILL BUT CAN I REALY GET IT OUT OF WHACK IF ITS NOT PERFECT. WHAT ABOUT THIS IAC AND CLEANING THE THROTTLE BODY. SHOULD THIS BE DONE IF SO LEAD ME THROUGH IT A BIT. IN CASE YOUR WONDERING I'M NOT A STUPID GUY JUST A FEMALE SHADE TREE MECHANIC TO UNTRUSTING TO GET RIPPED OF AT A GARAGE.

 

[c4ever]

Well Wildlife you're in FL so you better find a shade tree to work on her:L
Code21 is TPS (signal voltage high) Code will set if TPS signal voltage is > 2.5volts for 4 seconds
The following is from my 82 which is crossfire but I'm assuming the same diagnostic as the 84 crossfire.

Diagnostic terminal not grounded
Disconnect neg battery terminal to clear codes.(1 minute)
Disconnect TPS sensor
Reconnect neg battery terminal
Start engine and idle for 1 minute or until check engine light comes on
Ignition on Engine stopped
Ground diagnostic terminal
Code 21 is present
Disconnect black ECM connector
Probe harness connector pin 5 with a test light to ground
No light-replace ECM
Light-Repair short to voltage CKT 417: Ckt 417 is pin5 on ECM connector to TPS B terminal
If code 22 is pulled
Probe Pin 11 on ECM connector CKT 452 with test light to 12 volts
Light
Replace TPS sensor
No Light- Repair open Ckt 452 : Ckt 452 runs from pin11 on ECM connector to terminal A on TPS sensor
Pretty easy actually. The only problem is I don't know where the ECM is on an 84


Hope this helps. Remember this is fron an 82 crossfire. Maybe others like Vig can confirm accuracy.
Carlo

By the way, your TPS should be set at .525volts (+/-) .075
Reading takes place between terminals A and B with sensor connected, ignition on, car not running.

 

[c4ever]

Crossfire has a completely different set up Len, more like a carb really.
Carlo

 

[vettl83]

The ecm is located under the dash on the passenger side. Two 10 mm nuts are all that stand in your way once you remove the panel under the passenger side dash. I had to lay on my back with my legs draped over the back of the seat to remove mine. If the ecm does need replacing Turbo City has updated ones for the CF cars, www.turbocity.com Good luck 84 CF 91 ZR-1