I have a 1983 244 GL and it starts great but the idle is really choppy. I can drive it on the highway but it wants to die when you stop at a light and the idle revs up and down between 800 and 1300 rpms. It just keeps going up and down and doesn't calm down no matter how long the car has been running.
I am stumped... Could it be the computer controls? I think timing is controlled by the computer. Or is it the injectors? I am having a hard time with this one. Has anyone else had a similar problem?
Can Anyone help me?
Many thanks.

 

Haha, I need to change had to has then it would be me. My car has the same problem and I was about ready to start a new thread about it. But first let's see if it's exactly the same. When my car starts up, it runs fine until then engine starts getting warm. Then I get problems. Then the idle starts to hunt. It looks like it happens when the computer makes the switch from the "warm up" program to the "running idle" program. When the computer is trying to regulate a normal warm idle, it's messing up causing the motor to hunt from a low-rpm sputter to a racing idle. My car has one more symptom, that I'm not sure if it's regulated or not. When starting the car when it is already warm (like I just drove it) it will crank away for a long time before it will catch. However, if you crank it for second, stop and the hit it again, it starts right up. It may not be related, but I think it is because both problems seem to be related to the engine being warm. See if your car is acting the same way. That will at least show if we got the exact same problem.

My car is a 745 Turbo. I tried to solve this problems years ago (I left the country for a while) but was unable to before I left. Here is my old thread on that http://forums.turbobricks.com/showthread.php?t=89810 . You can try things in there. If one of them works, tell me. Maybe I did something incorrectly.

Another question about you car's problem, when did this problem show up in your car? After service? Mine showed up after I removed the intake manifold and cleaned the PCV system. It seems to be unrelated to that job I did.

The first thing I did check for is vacuum leaks. That's probably where you should begin. Inspect the hoses all going into the intake manifold. You can also spray lighter fluid, carb cleaner or I think WD-40 works too on the places where tubes connect to their fittings. If it noticeably changes the idle from it's normal pulsing you've probably found a leak. Just be careful spaying flammable liquids around the engine compartment. It will probably be a good idea to have a fire extinguisher nearby.

 

For surging idle the first thing I would do is clean out the idle air motor also known as the idle air controller (IAC). It sits below the throttle body and has two hoses on it. They look like heater hoses. It is meant to bypass the throttle at idle. It gets gunked up sometimes. Spray some throttle cleaner in there. You can also apply 12v to the IAC and see if the valve opens and closes.

 

On these old CIS motors there are vaccuum lines everywhere. I would just replace every single one. My car did the same, ended up heater flap vaccuum had its vaccuum hose slip off. Had to go under the dash to fix that.

 

Or should I say I finally got back to post my solution. It was the air mass meter. I got a new one from FCP and now the car drives like a dream. Well, maybe not a dream, but I sure do love this thing. Now onto the leaky trans oil cooler line. It can't be good to have that dripping everywhere!
Thanks for everyones help.
These forums are awesome!!!

 

I'm glad you were able to fix your problem but how did you know to change the mass air flow sensor and not the idle air controller or any other parts? I have a 940 and it idled rough so I turned up the idle several months ago. Now it doesn't idle at all.

How much did you pay for the part at FCP?

 

Dont forget to seafoam...can help clean crap from the engine too.

 

Good ol' seafoam. Forgot about it. Worth a try for only $7.