henningmd

I have a stock 1985 gs with a 12A engine and it has just started to not idle. When I mean stock I mean that I am the original owner and it still has the original Rx-7 floor mats! I have not worked on it or had any work done no it lately

I did a search for idling problems and it seems that the majority of responses indicated that it is most likely a vacuum leak problem or a problem with the pneumatic circuit that deals with the shutter valve solenoid, coasting valve and shutter valve and to a lesser degree the anti-after burn valves, idle compensator and altitude compensator.

I want to thank members who respond to people who like myself are not very mechanicaly orientated.

That said since my car will start and run fine when the engine is cold. It will also idle fine when cold with the choke pulled out. Once the engine warms up it will not idle at all. When I push in the clutch to coast or come to a stop it just dies.

Looking through the electrical schematics in the factory service manual I found that the choke magnet is energized via the No. 1 water temp switch. Now I believe that this switch is located on the water pump near the top and it is closed (conducting) when the engine is cold. I was wondering whether I could disconnect the switch and install a jumper in its place to keep the choke magnet energized and thus allow me to use the choke to keep it idling (fast but at least not dieing).
I thought that to make sure that I had the right connector I could disconnect the switch and check if the choke would stay out when I tried to start the car. If it did not I had the right connector.

I was wondering if anyone had any thoughts on my doing this for the time being until I could get the money together to take it into the Mazda dealer. Russ Darrow Mazda is the only place that I know of to take it to in the Milwaukee, WI area. As I said I'm not very mechanically inclined or I would try to fix it myself.

74RX4

iTrader: (10)

Check the #2 anti-afterburn hose carefully. It is directly above the hot exhaust. It can develop a split on the bottom that seals when cold and opens when hot. It causes a large vacuum leak.
For some reason the thread that I started is not available?
https://www.rx7club.com/1st-generation-specific-1979-1985-18/hose-question-750125/

Kentetsu

If this happened all of a sudden, I would confirm that you still have spark on the leading ignition system (lower spark plugs).

Otherwise, here is a tutorial on how to tune the idle, which might help you out: http://sterlingmetalworks.com/idle_tuning.htm


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henningmd

Interesting. Yes it did happen all of a sudden. But if I lost the spark on the leading ignition would it still start fine hot or cold, run fine at idle when cold, run fine above idle hot or cold and just not idle at all when hot.

Also nobody seems to be able to answer my question about jumping out the no.1 water temp switch for the time being.

Kentetsu

Well, rigging the choke release is a way to live with the problem, rather than fixing it. I would recommend that you do not go down that road. Its always better to just fix the issue itself.

Loss of leading ignition would result in performance loss, and high exhaust temps....