97VetteDan

Ever since I swapped the B&B Cat Back Exhaust from my 98 to my 97 I've noticed black sut collects on the rear end after a couple days of driving. Unfortunately, during the swap I had to reuse 2 of the 4 flange gaskets because B&B discontinued my particular exhaust in 2005 and therefore does not make the gaskets anymore and I can't find them anywhere. So I reused the gaskets with some liquid gasket sealer. I was thinking that the old gaskets could be burning off and collecting on the rear end? Is this plausible? What else could it be? The whole time the B&B Exhaust was on my 98 I did not have this issue. I also did not have this issue with the exhaust that was on my 97 previously. Thanks for everyone's help!

RedZMonte

doubt it is gasket burning off. Black sut usually indicates rich fuel system. chances are it was in the pipes before. the stock mufflers are chambered and usually will catch it not allowing any sut to come out. stright threw mufflers wont hold the sut in. look in the pipes of the muffler that came off where it connects to the exhaust, bet its black in there as well. might be time for a tune up, New O2 sensors, Clean MAF, catch can for PCV and/or maybe a tune.

For example... Honda Civic stock is clean as a whistle... slap exhaust on it and it smokes and bumper is allways black with sut.. not caused by the muffler but happends with the muffler if you know what i am saying.

S

97VetteDan

Come to think of it, I had an 02 sensor code come up regarding an overheated sensor a couple weeks ago. The ECM might be dumping extra raw fuel into the intake to cool the sensor down resulting in the black sut I'm getting. I think I'll start with replacing the 02 sensors and cleaning the MAF. If that doesn't take care of the problem I'll move to the PCV. Thanks for your help!

Supercharged111

If I'm not mistaken, the only O2 sensors that throw hot codes are the rears, which may be an indication of a catalyst problem.

97VetteDan

I've now replaced all 02 sensors and cleaned my MAF but I'm still getting a collection of sut on the rear. My car is running better since the recent maintenance so it wasn't for nothing but I'd like to get rid of the black sut. Does it take some time to relearn new fuel trims? Should I disconnect my battery so it can now relearn? Or should I go ahead and replace that catch can RedZMonte talked about? I also have a HyperTech Power Programmer III tune installed. Not sure if this would effect anything.

97VetteDan

I have changed Spark Plugs and cleaned my Throttle Body and Air Filter since my last post. Soot still collects on the rear end. I've thought about a catch can, but my 98 had the same exhaust without a catch can and did not have any soot issues. The only other thing I can think of is to remove the HyperTech Power Programmer III tune which my 98 did not have and see if the problem persists. However, I thought that the HPP3 tune leaned out the car? I've also heard somewhere that I might need to Re-Ring my LS1? It seems to burn about 1 quart of oil every 3,000 miles. It's got 89,000 miles.

97VetteDan

I've done Plugs, O2 sensors, Cleaning of the MAF and intake and installed an oil catch can. Unfortunately, I still get black sut collecting on the rear. Any ideas where to go from here?

NITRO UK

Hi
I would try putting the stock tune back in ,give it a good run and see what that does.

97VetteDan

I put the stock tune back in and it's still collecting. Here's what it looks like:

97VetteDan

bump

Bandit 00C5

Look for an oil leak of some type starting from the engine back. What you are seeing is generally very indicative of such a problem. I have the same exhaust as you and my rear bumper looks the same over a few days. However, my front crank seal leaks and makes its way to the rear.

97VetteDan

I've known about transmission fluid leaking from the Front Pump Seal area since February 2014. It's not a major leak but perhaps it's to blame for the splatter pattern? The thing is, I swapped exhausts in November 2013 and did not notice the sut with the chambered stock exhaust . Maybe the transmission leak just happened to start around the time that I swapped exhausts which led me to think it was the exhaust...