Hi all, it's been a while since I've been on te forum here, but I'm glad to see that I can still participate in discussions. Okay, here's the concern I have:

The other day I started up my RX for the first time in a month or so (yeah I know, but the engine needs a rebuild and I have put it on the back burner for now until I get enough dough to do it right).
It smoked a lot, but in about 5 minutes it was pretty much gone. The engine idles really high right now also because (I think) the thermowax pellet in the TB is bad, not allowing the idle speed to come down.
After about 5 minutes, I moved the car a few feet to get to a water hose just so I could top off the coolant level, and noticed that the #1 header pipe was glowing orange-hot. The #2 pipe was not. Hmm.

Now, the idle was really high at this point in time (about 2-2500K RPM), and the car was just sitting while still warming up. Does this mean that there is something else going on inside my 1.3L beast? I'm going to rebuild it anyway, or do a TII swap, but I would still like to know since I do drive it around occasionally. Could the coolant somehow not be cooling off the #1 rotor chamber, or is this symptoms of combustion problems? The car runs really sweet; just faster than it should because of the TB problem.

If any of you have any ideas, let me know. Thanks in advance!

 

My brothers FD did a similar thing with the his down pipe glowing red. he wouldn't even push it it would just start glowing red after a normal drive. We don't know exactly what casued it but we do know that we had to get it rebuilt shortly after.

 

My guiess would go to running lean. The leaner your engine runs, the hotter your EGT (exhaust gas temperature) is. That's one of the reasons I've heard that our cars run pig rich from the factory, to keep the EGTs low enough to not burn out kitties (allowing them to pass inspection). i'm guessing your primary fuel injector is clogged/dirty and now allowing full flow, causing a lean condition.

This would obviously cause an engine failure, especially in a turbo engine such as the third gens' TT engine.

 

It's normal. Don't worry about it. It's why you should never park over loose paper or foliage...

~edit...didn't read the whole thing. They should both glow, not just one. Mine did that briefly before installing new injectors. I was also getting heinous economy and rather lacking idle~2500rpm throttle response. New injectors cleared it up...plus typical fuel system tune up.

 

Awesome. Thanks for all the information. Since I'm going to do a rebuild on it anyway and I hardly drive it anymore these days, I'm not too worried about it, but it is good to know that it seems to be a fuel problem for sure. This was the first time I saw it and was worried since it wasn't happening to both exhaust pipes.

Thanks again, see you guys later

 

People are continually stuck on the concept that a lean mixture will make a downpipe glow, and I don't know why. 99% of time in the RX-7, the exhaust glows because it is TOO RICH. Excess fuel is burning in the manifold/downpipe. Normally, curing this on a stock car is as easy as doing a full tuneup, paying attention to plugs, wires and TPS adjustment.

Never have I seen a glowing exhaust due to a lean condition.

 

I'm stuck on it, cause I've seen it on boinger engines... I didn't realize that this didn't apply rotary, 'cause the theory seemed to hold, well, gas I guess And normally a lean mixture is the only way to get that pipe that hot, short of gasses burning in the header (which obviously can happen very easliy on rotary). I'd believe you, though

 

check timing too, too much advance can cause this......

 

I didn't remember the specifics, so I did some Googling and found a site that talks about EGTs and fuel mix in an airplane. As you ascend, the air gets thinner, which richens the mix and lowers the EGT. You lean the mixure to get the EGT back up again. I can't imagine why this would be any different in a rotary.

 

That's not what's wrong in what Aaron is pointing out.. Rotaries don't break physics or anything, and leaner still leads to higher EGT... What Aaron is saying is that in his experience, most of the time this problem occurs, cars are running too rich, causing excess fuel to ignite in the exhaust port/header, creating fire and higher temps in the port/header. Remember, that's why rotaries have higher EGTS in the first place is because there's not as much down time before the exhaust gas is pushed out of the rotor housings.

Makes sense to me, anyway