Hello,

I'm having trouble with my '82 RX. It starts fine and idles good, after warming up it will drive fine for about a half a mile. After that it starts running bad. It feels like it may not be getting fuel. Car will buck if you pump the gas pedal. It often dies but will start right back up(makes me think it's not ignition related) This car has not run for several years and has recently been started. I just replaced the fuel filter and ran the car, still had the problem. Could the fuel pressure regulator do this? Or does it sound like a carburetor problem? I am relatively new to this and would appreciate any advice. Thank you for your time.

 

Hi and welcome to the forum. If your 7 is stock then there isn't a fuel pressure regulator. Try using the search function with specific terms and you should find a lot of info. Since you're new you also need to read the FAQ to familiarize yourself with the forum and your car. Are you using the manual choke and letting it warm up to operating temperature? With the choke all the way out it should be at about 4000rpm until she's warmed up. You could have old or bad gas, that's certainly a possibility. Check around for any vacuum leaks on the carb, loose hoses, etc. as well. Listen for a hissing sound that would indicate a leak. If you hear a honking noise then your air control valve is bad. Check on those things and then come back to the forum with your results and post them here.

 

Unless stored correctly (either storage-treated gas or emptied tank) - gas goes bad, leaves crap throughout the fuel system - and worse, partial-filled (then stored) tanks can create rust internally, which is then constantly shedding and plugging your fuel filter. First, if you are still running the car with the "original' gas, drain that crap out! I am sure the 82s have a drain plug (help me here FB guys) - I know my 80 SA does NOT ;p
You might be looking at pulling the tank, getting it to a good rad shop to chem-dunk it and clean the junk out, then reseal with a gas tank sealer kit like the one POR15.com sells. Had to do this with one of my SAs - was doing the same thing as yours, usually after the tank got below 1/3 full...
good luck and welcome to the forum
Stu Aull
80GS
Alaska

 

Thanks for the advice. I've looked through the FAQ but didn't see it. Although I wasn't aware of a search function. You say that it should idle at 4K with the choke pulled, Mine idles at about 2-2 1/2 K with the choke pulled. I did notice what appeared to be rust discoloration in my old fuel filter but haven't pulled the new one to check if it's got rust in it. I syphoned the tank before I put new gas in though rust may be a possible problem. If that is my problem can a standard auto shop do that gas tank treatment? Or will I need to find a Mazda shop? Otherwise you say it may be a vac problem. Which is about where I get confused. I have the diagram of those weird color coded solenoids and can probably find a vac diagram, though I have no idea what I'm supposed to be looking for. I haven't heard any hissing to indicate a leak but I really can't hear anything with the fan running. Any ideas would be helpful.

 

Correction on the honking noise.
If you here that noise it is the shutter valve that is bad not the ACV.

 

I had similar problems reviving an '83 that sat for 13 years. There was so much crud in the tank I ended up taking it to a radiator shop and had it boiled out, and the pick up and return lines replaced. It still had enough rust in it to clog a filter after a mile or so. I pulled the tank back off it, and using a kit I ordered off the Internet, Marine Cleaned it, Metal Etched it, and POR15 sealed it. No more problems!

- David

 

I just pulled the fuel filter back off and checked it out. No rust, no chunks! I think that may not be my problem at all. I'm going to replace a bunch of fuel and vac lines tomorrow. Could it be a carburetor problem? It's gotten to be all the time now, not just after awhile. Or maybe an ignition problem? I think it's starting to fit the bill for it, it happens all the time and could possibly be due to heating up. I'm still using the plugs, wires, and distributor that it had. Still waiting on parts...