Technical Need Help - Slow Idle

[RS Pilot]

I'm pleased you found an air leak - we're a step nearer to getting it running correctly!

Does your distributor have points in it? If not I'll need to find out if you have any timing marks to use. With points it real easy (once you disconnect the condenser!). I'll check and feed back.

 

[beng]

Well, it seems the problem is definitely involving the polution control system. Although I need to get a gauge to check my vacuum, It would seem as though the idle issue is clearly related to various valves on the EGR system are stuck in the open position (or at least it is the theory that seems most possible). As I had indicated earlier, there was an air leak between the carburator and the manifold which made a noticeable difference but not enough to solve the problem completely.

I set the timing with the light with the lowest rpm I could achieve (about 1000 to 1200 rpm). I could not get any readings from any of the leads from the distributor as my system does not have points (electronic ignition model).

Although this is frustrating as the summer season in Canada is winding down and I don't have much time to work on it, I am encouraged that we are finally getting to the root of the problem. I will be chipping away at this over the next few days and see what I come up with.

I will report results.

 

[beng]

Well, the verdict is in! Turns out that the EGR valve is stuck open allowing exhaust gases to enter the intake manifold during low idle. This combined with the air leak in the carburator was the problem. I temporarily disconnected all the polution control lines from the carb and manifold (plugging them) and suddenly I get good low rpm idle, my vacuum readings are up and I can set the timing easily with the timing light. Although the job is not done as this was not made permanent, I now know what went wrong.

Thanks for your help in this matter as I learned a few things along the way. I suspect this may be a problem in only the North American cars...or I may have one of the last cars with this system still in place (not for long!). I have attached a picture of my cars. The purple one is the '79 which has been the subject of this thread.

Now on to performance...any ideas?

Thanks