Exhaust Soot

[Elwoody]

Just making a quick post here. Something that I noticed about a month after buying my wag was that it was throwing out soot -- I noticed because of staining on the frame around the garage door.

I've been talking with Chumley, and he noticed that the PO never hooked up the vacuum advance line. (Chevy 350 engine). At first I didn't really care, the PO had said that the VAL really didn't need to be hooked up. I mean it does drive pretty well, I wouldn't say perfect.

As for the soot, it's starting to become a bit of a problem with me mum. I mean I don't blame her, but what really to do? Here's a pic below. I'll be back to add some more stuff later.

[aatcman]

Wow,

Soot blowing onto the wall. Sounds like incomplete combustion to me.

Several possible causes:
-Too much fuel (running rich)
-Not enough Air (plugged air filter, stuck choke, etc...)
-Partially plugged exhaust (stuck heat riser, damaged catalytic converter, damaged muffler, smashed tail pipe, etc....)
-EGR valve stuck open -- this will allow too much exhaust to be redirected into the engine at low RPM's (such as idle) and displace the air needed for combustion.
-Incorrect Timing (timing set wrong or timing chain worn out and possibly jumped)

You should definitly connect the vacuum advance -- BUT CHECK FIRST to make sure you have the factory ignition!! -- Sometimes aftermarket ignition kits direct you to disable the vacuum advance. -- if nothing else, connect it to manifold vacuum.

What is your fuel milage like?

If you open the hood, do you smell gas?

Just a few ideas to start with -- many many ways to go with this one -- too bad I am in the DC area now -- I was in norfolk for years -- would've invited you to meet me somewhere and taken a look at it for you!!

Hope this helps

[710 Burner]

I don't have an answer. I thought it was too much choke mixing with the water in the exhaust, but if I try to adjust it out, it won't run cold.

[Greenfish]

Mine does the same thing. Let me know what you figure out.

[leostevo]

My '90 GW is doing the same thing on startup. After it warms up and the choke backs off then I can check it by holding my hand or paper up to the tailpipe and it will be clean.

Waiting to see what you find out. I have a recently rebuild motor. I am thinking it may be the old exhaust and cat. (256,000 miles before the rebuild)

-Steve

[[]V[]AXX]

Welcome to E10, soon to be E15 if the *@%$ EPA has it's way. I've enriched the mixture on my six banger as much as possible without it bogging, and now I get soot like mad. There are probably other reasons it's doing it, but FSJ's weren't set up to run this junk.

[jaber]

I had a Chevy with a Edelbrock carb on it and it did the same thing. I rejetted the carb to smaller jets and it went WAY down. It sounds like you are running rich, but this could also be from other issues as stated above.

[lost1]

I've got the same problem... I'm running a cat with nearly 300k miles on it though, so I suspect its a combination of that and a rich mixture.

The cat gets a violent death on Thursday.

[Chumley360]

We need to get in there and check some stuff. But haven't had the time.

I can tell that the PO of Elwoody's Wag cranked up the timing and then locked it. You can hear it when it's starting. Also when we put in his new t-case I noticed that it didn't look like the choke was opening up all the way. He's got a Chevy 350 swapped in, running a Q-junk with the old thermo-spring choke on an aluminum intake. I don't know why the PO didn't, at least, run an e-choke carb. Personally I'd drop the carb for a Holley or maybe even a FI setup, but that's me and I don't get around to half of my ideas. I'm with everyone else though, start with the simple checks and get the timing set and the advance working. Anyone know what port on a Q-jet the advance runs off of?

[skeletor]

is it just at startup or all the time? if just at startup could just be condensation in the pipe.

[Elwoody]

Thanks for all the info, I think I have a decent idea of where to start.