ssl47

I have a 1991 C4 w/automatic transmission. On a recent trip I noticed the console getting really hot. Eventually the car started choking for gas and quit. I ended up with only low gear working, nothing else. Turns out the catalytic converter was plugged which melted the heat shield which in turn melted the transmission cable. I replaced everything and drove it 100 miles and the same thing happened again including the console getting hot. Any ideas on what might be wrong? I was told the exhaust pipes weren't getting any air out and turned black inside. Possibly an injector or fuel regulator? the car only 60,000 miles on it. The mechanic told me he doesn't think the transmission fluid was ever flushed and was worried I would lose the transmission of he tried it. The other alternative is for it to just go out on it's own from not having it flushed. Any ideas?

FASTAZU

You may want to post this in the C4 section as 99% of all ZR-1's have 6 speeds. And yes you could have cooked the transmission.

A26B

Raw fuel can overheat the catalytic converter & fuse it together, plugging the exhaust. Having it happen a second time says loudly, there's a problem.

Don't flush the tranny, remove the pan, change the filter & replace the fluid. You can flush all day, but it does nothing for the filter or cleaning out the solids in the pan. At least there's a chance it may live if you do. If you do nothing, expect the worst.

Goldcylon

Another thing to look at is if the rubber shift boot is cracked/ripped or torn as that will allow a significant amount of heat into the car at the console in the cup holders area. I know this does not solve your transmissions problem but it is something to be mindful of once you do get it figured out and pieced back together. GC

TomH91

Did you replace only the main cat? If you replaced everything ignore the rest of this post. If you replaced only the main cat, read on.

Your 91 has two small pre-cats following the intake manifold plus a large center cat. If you replaced only the main cat there is a good chance there is still a problem with the precats. I had a precat fail on my 91. It wouldn't rev past 2500, ran hot, etc because the precat substrate had broken up and would block the exhaust stream when there was enough gas flow. Everything looked fine with the main cat, resonator, mufflers and tailpipes when I pulled the exhaust but upon pulling the front Y pipe(s) the problem was immediately evident. You may need to replace the Y pipe to solve the problem. Good news: the front Y is available, with or without precats, from the aftermarket.