In trying to make my 1980 RX-7 S not have such a STRONG exhaust smell, wondering if it is possible to make the trailing plugs fire at all RPM ranges. Might this help?

What are the top few things to check to get rid of the strong exhaust smell?

Smell is strongest when coming to a stop after driving at high speeds.

Thanks

 

My 80 is wired like yours and have no such problem. Assume you exhaust is tight? no leaks (your ears would know it! ? What shape is your hatch weather seal? If its the original and particularly if you have the car under the open sky 24/7 AND live down south, the rubber could be well on its way out...
Stu Aull
80GS
Alaska

 

Thanks for the suggestions.

I bought the car new in 1979, and it has always been garaged. No exhaust leaks, the hatch and door seals are good (tail light gaskets could use renewing). Good to hear of an early RX-7 that doesn't stink... this forum might lead to believe they all do.

I would still like to have the trailing plugs firing all the time. Is that controlled by the control box behind the fuse box, or the distributor, or ???

 

Check that your air/fuel mixture is good. If you're running really rich you could be smelling. If you're running crappy gas you could be smelling.

Carb and ignition is where I'd check first. As long as they're working properly you should be good.

Jon

 

Perhaps the 'fire' has gone out in the thermal reactor? I've got a '76 Cosmo that used to wreak horribly out the tail pipe. The emissions systems were old and didn't seem to function anymore so I left the airpump on and even got a new belt for it (if you remove the air pump but continue to use the thermal reactor, the heat can damage apex seal springs if one of them just happens to come to rest over the exhaust port when the engine is shut off). I upgraded the funky stock three points dizzy to an FB dizzy and DLIDFIS and the exhaust smell improved substantially. If you upgrade your ignition system, your car may not be able to pass emissions anymore, and the exhaust smell may get worse, but chances are nearly equal that it will be improved like my Cosmo was. The engine will also run much better and make more power while improving gas mileage (for the same type of driving).

The '80 ignition has a box on the inner fender that has two J-105 ignitors in it. The box sometimes turns off trailing depending on the cues it gets from emissions devices. You can replace the box with an aluminum plate which acts as a heat sink, and hook the leading pickup signal wires to both ignitors in parallel. Then hook the C and B terminals of the ignitors to the stock coils and then hook both coils directly to both leading plugs. This mod will most likely make a big difference in your engine's power and driveability, doesn't cost anything if you've got some 1/8" thick aluminum laying around, and trailing won't even be necessary as the leading plugs' second spark 180° later can do trailing's job, the spark is also unshrouded. Your engine will actually sound like a 2nd gen RX-7 (it's a much smoother type of sound), which I like because I think it sounds better.

Just a little bit to think about. Of course you could also run trailing for an extra 1% power and a little less emissions. You probably won't notice the difference though. I'm just trying to save you some money.