Another day of issues in the life of a 1984 Crossfire Vet. Cruising around today car running really good,get within 2 miles of home at a stop light rpm dropping and then rising don't know if the car is starving for gas or getting too much gas. When car is in park the idling hovers around 7000 rpm when in drive goes from 7 down to 4 and sometimes the car just shut off.Don't want to start guessing about parts that can get a little expensive.The car only has little over 80 thousand miles,beginning to believe the sitting around has done this car more harm than good.Was thinking about replacing the EGR VALVE OR THE TWIN IDLING CONTROL VALVES.If anyone has a good suggestion I am all ears, Hope to hear from someone soon.

 

Meant 700 RPM

 

Codes? Vacuum leaks? Condition of injector connectors, fully connected and wires not pinched at air cleaner

 

I had a similar problem with my '84 and an erratic idle, usually too high. I pulled both IACs and found them to be quite dirty. I also found whoever had them out before didn't replace the gaskets but instead put some sort of sealer on the threads. Local parts house didn't have correct gaskets so I made my own with gasket material. I cleaned the pintles with carb cleaner. cleaned the ports in the throttle bodies, pushed the pintles in slightly and reinstalled them. Fired it up and had a high idle due to having pushed in the pintles but a test drive took care of that once the ECM had time to make corrections. Per the FSM it can take up to 35 miles of driving for things to get right. Now I have an idle at 700 when fully warmed up and 1200 when cold, not the 1700 cold idle I used to have. A very inexpensive fix to try first before spending the $75 cost of each new IAC.

 

Are the IAC'S same as the twin idling control units inside the air cleaner unit if not can you tell me where they are located

 

First thing I did was to check for vac.leaks found none. Can the Injector Connectors be clean, ( If so with what ) .While I look at the connectors will make sure that they are not being pinched. Also could the Twin Idling Control valves be a issue

 

Started the beast up this morning,the gas smell was overbearing,as I watched the info window I could see the check engine light flickering and the car was idling ruff.Somewhere along the line I read that a bad erg valve could do this. If you have any suggestions I am all ears

 

See if you have any codes.

 

Check engine light on should be codes. Back fire can melt connector also they can get brittle with age and be unable to stay tight on injector(s). Check condition of coolant sensor the connector the early round style tends to fall apart with age. I would replace both sensor and connector with the newer inline style if present. I would not condemn the IACs yet. Do you have a FSM or access to OBD1 scanner? EGR valve open at idle will cause rough idle and stalling at idle. You should be able to feel if diaghram on valve is up with you finger. Vacuum should not be going to valve at idle. I would also make sure timing is correct.

 

The Idle Air Controllers are on the throttle bodies at the front. Here is a video on where they are and how to remove them.

 

Thanks for the info tried driving the car,run good long as you are moving.when came to a stop light the the RPMS were chasing there self then it stopped on me,did it twice. Off hand where is the coolant sensor located. Again thanks for all your help.

 

I will have to find a older instrument ,the one I got is good for cars 1996 and up. Tried Auto zone they don't have one that goes back to 84. But I will find one. Outside of the problems I luv this car,bought it new,my first. Wish I had learned to work on earlier rather than having someone doing the work for me.

 

Yeah know, IACs are funny beasts and can cause odd idle issues. Case in point... We did a restoration service on a pair of TBs for a corvette shop client of ours including the a rebush job. After three days the shop calls us and says the TBs are bad and car won't idle and wanted to know if we could come out and check them out. Keep in mind this was three days after the installation and they couldn't figure it out. We arrived to the shop and tried to start just to see what it was doing or not doing, no idle. The first thing I did was short the test port and watch the pintles, no movement on either one. Asked if they had any old IACs around and installed two old IACs. Retested and both IACs would cycle. Started car and it idled really nice. Did a quick balance job and the motor purred like a kitten. Total time from start to finish less than 45 minutes. The shop was happy and we didn't even charge them, the price of doing business I guess.

Point being, IACs do cause issues and it could be both bad. Nice job Danlb thanks for the vid. BTW, do not over torque the IACs.

 

[QUOTE=Buccaneer;1592763666]Yeah know, IACs are funny beasts and can cause odd idle issues. Case in point... We did a restoration service on a pair of TBs for a corvette shop client of ours including the a rebush job. After three days the shop calls us and says the TBs are bad and car won't idle and wanted to know if we could come out and check them out. Keep in mind this was three days after the installation and they couldn't figure it out. We arrived to the shop and tried to start just to see what it was doing or not doing, no idle. The first thing I did was short the test port and watch the pintles, no movement on either one. Asked if they had any old IACs around and installed two old IACs. Retested and both IACs would cycle. Started car and it idled really nice. Did a quick balance job and the motor purred like a kitten. Total time from start to finish less than 45 minutes. The shop was happy and we didn't even charge them, the price of doing business I guess.

Point being, IACs do cause issues and it could be both bad. Nice job Danlb thanks for the vid. BTW, do not over torque the IACs.[/QUOT
I was thinking about replacing the IACs ,now I think I should try cleaning them first,are they one of these items that either work or don't work. Really don't know much about them. When I clean them is there anything that I should be aware of. Hope to hear fom you soon

 

[QUOTE=Klgrayson;1592765431]Yes, they either work or they don't. I've never seen one that is intermittent in my experience. If you clean them, do not turn them upside down and spray anything inside. Hold them with the pintle pointing down and spray the pintle to clean. If you suspect that they are bad by no movement, just replace them both, they aren't too expensive.

Also, if you have no movement, you might want to verify the harness is good first before replacing. The GM Shop Manual goes though that process. That manual is essential for any CFI owner.

 

Fellas,today I can come into this forum and actually say I have had a great day with my car.After having issues with Idling problems.Only thing I did was to change the Coolant Temperature Sensor,recheck all hose for vacuum leaks,and make sure all sensor connections were secure. What a difference in the performance.Wanted to say thanks to all who fed me advice on possible problems.I was planning on cleaning the Idling sensor,is that something done annually as a preventive maintenance thing.Or just drive it until acts up. Again thanks

 

[QUOTE=Buccaneer;1592775061]Off topic Hi-Jack. I'm Sorry OP

Buc, your Pm's are full again.

 

It probably would not hurt to clean the idle air control valves. My '84 just rolled over 36k miles. When I took mine out a few months back they were pretty gunked up. I just went ahead and replaced mine. I'm slowly going through the engine and swapping out all the 32 year old sensors and vacuum hoses.

 

I think at times I had let mine sit around too long ,I believe that did more harm than good. Most likely I will clean them. Then take your approach over the winter months and start replacing things

 

[QUOTE=Greg MFn Z;1592778219]Sorry for the HI-JACK, I'll clean that up today. Been getting a lot of those lately.
BTW, I'll be at your cars and coffee in the morning with Jim and his 84 right around 7am. Have hot coffee ready pleas. (grin)