Last winter, I bought an 83 RX-7 ($500) with a NA 12a motor with nearly 200K miles and a bad tranny. Two weeks ago, I mounted the $100 Ebay tranny and the Mazda was back in business. I drive 100 miles each day to work and I was keen to drive the RX-7 for a while at least before I rebuild the engine.

The first day, I noticed that while the car would do 75-80 in fourth gear, in fifth she would only pull 60MPH. The car seemed to run rich, and judging from the general condition of the car, I figured that a major tune up was in order. I figured that I would continue driving the car until the weekend.

Yesterday, the problem got substantially worse. The car would only do 60 in third gear (which I had to do to get home), all the higher gears yield 3000 rpm or less. The car has no power going up hills, and has started to backfire slightly. Sitting in neutral, I tried to rev the engine, and it hesitated and generally sounded bogged down. I took the air cleaner off, while I was looking at the throttle linkage and the car has been backfiring through the carb, blowing oil colored gas onto the air cleaner cover. I also noted a burning rubber smell when I removed the air cleaner cover.

The oil smells like gasoline, when I pulled out the dipstick to check for emulsification (none found).

I am new to rotaries, and I was wondering if anyone had any ideas or suggestions. I plan to do a tune up tomorrow, but wonder if the problem is greater that a new set of plugs, wires et al.

 

I would say check fuel flow... does it sound kinda like a lawnmower not running to well when it loses power, like not the normal atomic weedeater sound? I would say it sounds like your fuel pump is packing it in, but it could also be loss of compression.

Pull the large fuel hose off the carb and measure how much fuel comes out when the key is "on" about 1.1L should come out in a minute, so a 600mL pop bottle should be full in less than 30 seconds.

If that's fine, check the compression. Hopefully it's not compression...

Jeff

 

dont know about the fuel or burning rubber smell but it sounds like either a clogged cat or rotor oil seal gone bad. Check the cat first.

peace

 

I second the cloged cat.

Mike

 

A clogged cat will really do that only at higher road speeds?

 

If its not a clogged cat, try to atf trick. And as Keaponlaffen says, hope its not compression.

 

fuel delivery would be a problem too, that's what my car did when it was starving for fuel... and it got gradually worse. It turned out to be the pump.

Jeff

 

It's either a clogged cat, or your timing is way off or your distributer is drifting. I would check your timing. Mine was only a few degrees off and I had no top end, it backfired like crazy and idled like crap. I adjusted it and it's fine.