Ok guys hear me out first. Just recently bought a 85 gsl-se as a restoration project and i'm a complete noob at this rotary. My plan is to return her to original show room glory. She is completely stock and that is the reason i picked her up.

I'll try to be as brief and clearly as i can with her problem so bare with me, i really need your guys help. At first when i brought her home she idle at 1200 smoothly with the idle air screw all the way out. When i adjusted the idle to 850, the engine would buckle and shake violently at idle but she drives fine with no symptom. Here are a few things i've tried.

-Fresh oil change, changed all fluid on the car, cap+rotor, new wires, new plugs, new oil cooler lines and repaired that usual cooler neck leak.

-Removed throttle body, cleaned and lubed to brand spanking new and throttle shaft is not binding. It was gummed up pretty bad.

-Removed BAC valve, cleaned and function tested, A+ ok!!

-Removed and tested vac/vent solenoid, A+ ok!! Learned the functionality of these valves, simple and effective.

-Cleaned and adjusted fast idle cam, get it into fast idle mode again, before it wouldn't fast idle during cold start.

-Adjusted TPS after engine has warmed up, thanks to Aaron for showing me the method to adjust, A+ ok!! It was way out of wack.

-Adjusted dash pot valve, A+ ok!!

-Adjusted ignition timing, checked both leading and trailing marks, A+ ok!!

-Spray 2 cans worth of carb cleaner to check for vacuum leak, none found.

After all the works above, now the car idle at 1600 (surging between 1600-1700) and here are the new symptoms.

-Started beautifully in fast idle mode (2500 rpm), then idle at 1600 with fast idle cam disengaged.

-No changes in engine speed with adjustment of idle screw.

-Engine stalled with BAC valve disable, normal?

-Rpm would drop after snapping the throttle and the engine would stall.

-Spray 2 cans worth of carb cleaner to check for vacuum leak, none found. AGAIN.

-Checked the double throttle valve, diagphram function fine. Do the plates partially close? Or do they must shut completely when vacuum is applied?

Sorry for the long post, i've reached the maximum of my knowledge of the rotary and could really use some help. Searched and searched again and again but can't seem to find a definate answer. Thanks in avance.

 

idle screw?

 

No changes in rpm when adjusting the idle screw, the port is not clog, i cleaned the port when i had the throttle body out.

 

have you messed with the mixture via the variable resistor? have you tested the fuel pressure?

 

Make sure the air intake funnel (black 3" diameter hose) from the AF meter to the throttle body is not leaking. There is a seam in the middle of this hose held by a clamp. Have you checked/cleaned the AF meter door? I assume you have found this during your search.

http://nellump.net/peri/epi/firstGen...gslseIdle.html

 

Slight changes but doesn't do much. I'll fine tune that setting after i get everything running right and hook the tailpipe to a gas analyzer

 

I have no symptom driving the car, she just wouldn't idle at 800-850 rpm.

 

take off the dash pot see if it changes anything.

did you get new gaskets?

 

I've loosen the dashpot out and make sure the throttle is close all the way = no changes. I've also spent half a can of carb cleaner around the throttle body area, it doesn't seem to have a leak.

 

Okay...went outside and played with it a little. Since i've been under the hood the entire time i didn't notice the reading on the dash tachometer.

I hook up the timing light with a tach reading to the L1 spark plug wire and it reads 1600 rpm. On the dash tachometer it reads in the middle of 1000 rpm and zero. Which one should i go by? The engine does seem to idle high. Am i doing something wrong?

 

What is the tach on the timing light set for (# of cylinders)? Should be set to 4-cylinder (and 4-stroke if there is a setting for that).

 

No setting on the timing light, just plug and play. I would think there is a difference since these plugs fire at twice the speed of a conventional 4 strokes engine.

 

Okay. Since it is running just off 1 plug, it can equate ignition events to RPM..but it is assuming 720* crank rotation per ignition event (normal 4-stroke piston engines). For the rotary, with have 1 spark per 360* of e-shaft rotation for each rotor..so the tach on the light is going to read 2x too high. So 1600RPM on the light = 800RPM on the engine.

Sometimes there is a setting in case you are working with 2-stoke engines.

 

That would make sense, i will have to ask these Mazda techs on what timing/tach light they are using. If that is the fact then i don't have an idle issue but just stalling after snapping the throttle and that is totally different ball of wax to play with. I'll keep you guys up to date when i confirm the tach reading.

 

Any timing light will do. Just don't worry about the tach on it (use the one on the cluster). If the light has adjustable advance, just set that to 0*. Warm the engine up, get the RPM to about 800, and turn the dizzy to line up the leading mark. Then clip on to T1 and see if it is lined up with the 2nd mark. Don't need to do anything special, it is just like timing a piston engine (except for having to check trailing).

If you want to use the tach on the light to set idle, just divide by 2 (set to 1600RPM to get 800RPM).

 

Guys, i'm happy to report that i've found thte gremlin. As it turn out, i have a pin hole vacuum leak at a vacuum hose between my vac solenoid and vacuum delay tank. I really had to get in there and spray in order to feel the engine shake a bit. Fixed that sucka and she idle like she should.

Stalling after throttle also is gone. That explain it, that leak caused the BAC valve to have a delay in response to throttle closing. NO MORE STALLING.

There is another slight leak somewhere all the way down there that i have to track down. For now i'm happy without stalling. Thanks to all of you, this forum is really great.