Car is a 1983 gsl with 12a and nikki 4bbl.

History: I took it to the dealership because it was barely running and not running below 2000rpm. They adjusted my ignition timing and diagnosed that it was a carburetor issue, specifically the idle circuit. So i rebuilt the carb and cleaned out all the passages with compressed air. When i put it back on it made a loud grinding sound once for less than a second from the carb. The accelerator pump wasn't working. Nothing was coming out of the accelerator pump nozzles, and it died when the throttle was applied, although it was possible to just barely push it and have it climb. The float level looked good. So i opened it back up and realized i forgot to replace the check ***** and did that. I put it back on and it was revving and not vibrating! I was so excited. I turned it off and checked to see if there was fuel coming from the nozzle and there wasn't. My friend started it and the grinding sound happened again, the vibrations were back, and it could no longer rev.

TL DR/ issue: accelerator pump doesn't work. Passages are clear, replaced check *****, replaced diaphragm and gasket + nozzle gasket. No rips in diaphragm. Grinding sound once for less than 1 second, carb vibrates after the sound.

Im hoping someone has had a similar issue, or can help shed some light regardless. Sorry if my grammar is bad.

 

Hot start assist motor is making the grinding noise.

The accel pump has check ***** and brass weights.

 

Thanks, i was worried about the grinding sound. To clarify, the hot start assist cable is not connected to the carb. The correct brass weights for the accelerator pump are in their holes. And the lever works (pushes the thing into the accel pump housing with throttle).

 

You should unplug the hot start assist motor's electrical connector.

Perhaps some debris has gotten into the accel pump circuit or a check ball has gotten stuck. Time to take it all apart and spray some carb cleaner through the drilled galleys. I wouldn't recommend it if I hadn't tried it myself. Mine didn't have any debris in it upon disassembly. Not sure what I did, but the accel pump worked after I "rebuilt" it.

 

Im fairly confident the galleys for the accelerator pump are clean, but its worth a try. Were you referring to spraying out all galleys? Or just the 2 for the accelerator pump? Ill write back with my results. Thanks again for the advice, im glad i got such a quick response.

 

I'm talking about the one from the float bowl into the accel pump, and the other from the accel pump over to the nozzle. Make sure both are clean and able to easily pass fluid (carb cleaner). Then fully dry and reassemble carefully. Make sure the narrow brass wight is under the long brass screw (stamped 30) with a checkball at the bottom, and the thick brass weight is under the squirter nozzle, above the checkball.

 

The check ball at the bottom of the well gets worn into the casting and fits super snug after a while, especially if it sat awhile and has a little gum in it. I had one that kept getting stuck no matter how clean it was, until I pushed a tiny brass brush into the well on a dremel and lightly polished the seat...

 

I took it apart and sprayed carb cleaner through the galleys, and the liquid passed well. I sprayed the nozzle and the long brass screw with the long weight underneath. I disconnected my hot start assist connection. I started the car and the accelerator pump wasnt working. I warmed it up and shut it off and checked the pump, and it wasnt squirting.

Side note; my secondarys dont open, and some parts are missing for example throttle sub return, and secondary linkage

 

Sounds kinda like a hacked up carburetor. Some people are better off with fuel injection...

 

I can't believe Mazda took on a diag on an ancient car like ours. Kudos to your local Mazda dealership. I took my MX-3 to a Mazda dealership one time for a timing belt while I was at school.... they took 5 weeks and replaced (against my wishes) my P/S pump (rack was leaking this was a useless gesture). That was the first and last time I ever used an auto mechanic.

Did you get the spring for the accelerator pump on the correct side of the diaphragm? When you cleared out the orifices did you get the input orifice at the bottom of the accelerator pump?

Try this... with fuel in the bowls, take the accelerator pump off. If fuel comes gushing out then you know that the problem lies between the accelerator pump and the A/P jetting.



V6 MX-3's are non-interference motors, its a 5.0 hour job. Takes about 2 hours to do tops. It was a "Mazda" dealership next to a Ford dealership. I take it the mechanics working there didn't want anything to do with an old car that had been "messed with" but screw them slap the belt on and roll it out the door. Grumble grumble mutter mutter.