93 Z24 runs rough most of the time with bad exhaust fumes?

[bdf24]

Hi I've had my 93 Z24 for over 8 years now. Lately when I start the car it runs really rough and bucky. When you accelerate it's got a lot less power and sounds really weird (sort of rappy like a stock car but not as loud). But after you get over around 3500 RPM's it will run fine for a while. Then it will all of a sudden start again. There are no warning lights that come on while the car runs like this. Also it does'nt do it all the time. Sometimes I'll start it and it will run fine. But slowly it's been getting more and more frequent.
Some of the exhaust fumes I get when this happens is sulfer smell (strong) and something similiar to like that of ether (sp?). Both are strong smells. But at times when this occurs I can just hammer on the accelerator and it will run fine. But it is getting worse little by little.

I was told it could be the Cat. From being clogged and causing to much back pressure. Is this true?

Also it's not the TCC. That's been uplugged for years now.

[mtheis]

The sulfur smell would suggest that the cat is going bad. Btw, having that tcc unplugged may overheat the tranny at high speeds.

[bdf24]

Thanks for the reply. Would the tranny overheating cause it to run rough? I would'nt think so. But then again I don't know much about cars either.
It does seem to do it more in more humid weather. When it's more dry out it does'nt do it as much.

[mtheis]

I don't think the tranny has anything to do with it either. Another thing to look into would be a bad O2 sensor. It will make the car run rough and cause your cat to fail.

I hope some other people start replying to this thread cuz it's always nice to have a second opinion.

[bdf24]

I think I'll try replacing the O2 sensor once and see what happens. Just need to find the time to do it. Pretty busy lately.

[Sight N Sound]

Check to see if the cat is glowing orangish or red after running for a bit, if it is that means the cat is clogged and you need a new one.

A tranny problem will cause a car to run ruff if its a auto due to it always being engaged to the engine unless in neutral.

[bdf24]

It runs rough in nuetral too. I've had people suggest to look at the cat to see if it's glowing orange but I've checked and never notice it glowing or burning.

[Three_Fingers]

Plug wires. If you buy the cheap ones-they burn from the inside-out right near the plug, usually.
They'll mimic symptoms of water in the fuel tank, bad MAP sensor, bad fuel pump, bad O2 sensor, etc.

The sulphur smell from the exhaust is the cat trying to deal with an overloaded situation. Sounds like raw fuel is getting dumped into the exhaust- This will cause the cat to runaway and melt, eventually, clogging up the exhaust system and making the engine stop. (You'll know it when you step on the gas and it dies.)

Bad plug wires cause plugs not to fire. Non-firing plugs cause raw fuel to be dumped into the exhaust. Raw fuel in the exhaust eventually overheats and melts the catalyst which blows downstream into the muffler-clogging it up so your engine can't breathe.
Sounds like the higher RPMs cause these misfiring plugs to kick in intermittently. (There's higher coil primary/secondary voltage at higher RPMs-overcoming the resistance in the plug wires temporarily until all of the conductor is burned away. Resistance=heat. Heat=destruction.


The more they misfire, the more they foul, the worse the problem gets.
Mebbe I'm wrong here, but it just makes sense to check the cheap, easy solutions first.
There's two ways you can check for a bad wire.
1.) have someone you don't like much grab the wire right by the plug boot and put his other hand on the block or other chassis ground.
If the wire has severe resistance, that person will most likely do "the ignition coil cha-cha" There's one of your bad wires!...Now to find three other people.....

2.) Buy the $35 set of spark plug wires instead of the $18 ones and then pull off plug wires and replace them one at a time. Cut each pulled wire just above the plug boot and look inside for the conductor. It should look like a small ribbon. It'll be either black or some other, lighter color.
If all you see is a hole where the conductor was-there's one of your bad wires! The spark gap is supposed to be at the plug electrodes-not in the wire.

(I had this problem for about two weeks. Jammed a lotta drygas in my tank 'cause it was acting like it had water in the fuel (bucking, bogging out, misfiring under load, etc)....Got fed up when the problem didn't improve and started grabbing plug wires to check for spark....found spark! It went from the good part of the wire-thru my hand-thru the res of me and out thru my other hand which was resting on the valve cover. Cha-cha bigtime. cut all the wires at the plug boot and found almost all the center conductors near completely burned away. There was enough to carry current at idle to fire the plugs, but not enough to carry the load at higher RPMs. They just misfired.
Got the good wires-car runs like new.
Hope this helps. Sometimes it's the dumb shit ya don't consider that bites ya in the ass...

[bdf24]

I did change the plugs. But not the wires. I'll change those too. Also as far as the cat goes. I looked under the car the othe morning and did finaly notice the middle glowing a dull orange. I was dark out so I was able to barely notice it. So I'm assuming that the cat is plugged as well. I did originaly buy cheap plug wires a couple years ago. So your probobly right there bad. But I'm assuming the cat is bad as well. So that'll need to be replaced as well.

[Three_Fingers]

The glowing cat is an indication that there is too much unburned fuel in your exhaust.
They get really hot-but they should not emit light.
Chances are if your cat is lighting up, it's failing.
You'll need to find the source of the unburned fuel.
Either ignition faults or fuel delivery problems are at fault, usually. Something is causing incomplete combustion.