Been working on this one for a few months on and off trying to get the car driveable (stalling and rough idle). About 90k miles. Side note- car had very little run time over past couple years. Back then it had a bad flooding issue but fixed that. Did a lot already and am running out of ideas. Summary of what I did:
- replaced intake man. gasket and coolant o rings)
- removed AAVs, ACV, and air pump. Sealed openings that were left
- replaced coasting valve…it and the shutter valve appear good now
- rebuilt carb and cleaned everything really well. Used a thicker gasket on base to eliminate a small vac leak there
- float bowl levels in spec
- drained tank and put good fuel in
- checked in detail to try to find any remaining vacuum leaks. Cannot find any
​​​​​​- replaced plugs
- hot start assist cable disconnected

The carb rebuild&plugs was the last thing I did and that seemed to help the most. At this point by playing with idle mixture and idle speed screws I can get it idling pretty reliably without stalling at 1000 RPM but it’s rather rough. Increasing revs to 2000 or so smooths things out but I do notice a little “miss” … so even at those higher revs I think it could be a little smoother. Starts pretty easily now. I know the richer solenoid valve (on pass side of carb) is not working (tested it separately by applying 12v). but could that cause issues? I’m beginning to wonder if I have some kind of ignition problem going on. Thoughts? Thanks!

 

Not related, did you remove the cats? When removing the air pump, the cats will burn up without that fresh air.

 

About 20 yrs ago I replaced the stock cats with a Bonez cat + muffler system. Yeah I know if I leave the air pump off the cat will disintegrate. I don’t need the cat to keep the RX registered though. I haven’t decided if I’ll put the pump and the related valves back on. I removed them partially because I was just trying to rule things out.

 

You still have a vacuum leak is what I suspect. Richer solenoid can stay unplugged. Try putting a vacuum gauge on it and see how it reads. Should be a steady 19-20 hg at idle, if you see it bouncing, you still have a leak somewhere.

 

Thanks- probably a good excuse for me to buy a vacuum gauge….

 

Just wanted to close out this thread. I still plan to get a vacuum gauge and monitor it, but i was able to get it idling much better (900 RPM) and it’s now driving well. I found an open vacuum port -associated with the AC solenoid valve I think. Also tightened one of the brake booster vacuum lines… that seemed to help a bit. Then I pulled the distributor cap and cleaned all the rotor electrodes which seemed to be the last ingredient to success. I suspect replacing the cap and rotor wouldn’t be a bad idea. Thanks for the advice!

 

New cap and rotor and coils might help a bit like you mentioned.

How's the compression? Are they even for each face of the rotor? Also what test did you perform to determine a bad vacuum port or was it a visual test?

 

Thanks - getting new coils crossed my mind too. I did not compression check the engine (is a special compression gauge needed for a rotary?). I’ll admit that the possibility of a bad seal inside the engine occurred to me but I really did not want to believe it since an engine rebuild is something I’m really not in the mood for at the moment. The last vacuum related thing I did was to cap off the end of a metal vacuum line close to the AC solenoid valve. I think it used to be connected to the cruise control but I’d have to check

 

you can do a quick audible compression test by removing the fuse to the fuel pump, disconnect the wires from both coils, and removing the lower leading spark plug and use the starter to crank the engine and listen for hopefully three, solid whooshes from each rotor

 

Sounds like a good tip thanks!