Running rich all of a sudden (1 Viewer)

[JamesR]

Hello all,
Everything was great. I was sitting at a stop light and I noticed/felt a "burp". I drove a few yards before I could pull over. It was smoking from the exhaust and under the hood. A buddy of mine told me he thought it was the EGR valve that may be stuck. The same thing happened to him and it was his EGR. So if you are familiar with that situation you have a good idea what was happening to me. Here's the "catcher" ...my 86 is desmoged and I don't think I have an EGR valve.

Since my engine is desmogged, is there some type of valve in the part where the blue circle is?
Thanks.

 

[GeologistFelix]

Check the fuel level in the window on the side of your carb towards the radiator. If it's above the middle after everything is running and warmed up, you might have a stuck valve or float, try giving the carb a firm whack with a rubber mallet or whatever else your favorite non-marring thumping tool is -- if you're lucky, it'll knock something stuck loose. Other signs that it's a 'too much fuel in the bowl' problem would be if it idles high while it's having the problem, and if the smoke you're seeing smells like gas.

 

[JamesR]

Thank you. This gives me a place to start. Now...a probably dumb question or two. Does it matter where on the carb I smack it? Would it be best to remove the air cleaner assembly?
Thanks again.

 

[GeologistFelix]

You can/should leave the air cleaner on at this early stage. The parts most likely to be sticking are in/around the fuel bowl, so the top part of the carb, on the the front/passenger side 'corner,' where the fuel line goes into the carb. Keep in mind that it *is* cast aluminum, so don't go totally medieval on the poor thing. More like a good, firm tap with a rubber mallet than a smack, if you know what I mean.

 

[JamesR]

Understood - thank you.

 

[JamesR]

I saw there was fuel in the carb looking through the site window and I got my rubber mallet and gave it a few blows. I was hesitant to do this...didn't want to mess it up. I started it and there was no change. I put my hand at the exhaust pipe and held my hand there for a few seconds. When I removed my hand there was a black moist "sut" type stuff on my hand. I'm going try the mallet tomorrow again. I'm concerned.

 

[1MOA]

When they desmogged your 86 did they remove the catalytic converter? it could be clogged.

 

[JamesR]

The catalytic converter is still there. Is there a way to check that without removing it and replacing it with a section of exhaust pipe? I don't mind doing the work; I would prefer not to if it's not going to change anything.
I appreciate your input.

 

[GeologistFelix]

When you saw fuel in the window, was the level centered in the middle, or higher, or lower? If it wasn't higher, you can probably cross off 'stuck float or valve in/around fuel bowl' as your problem.

Other than soot from the exhaust, is it showing symptoms of running rich currently? Like, fuel smell from the exhaust? If there is a strong fuel smell, is it happening any time the engine is running, or just at idle, or only when it's cold or only when it's hot? Anything else specific it's done that might help narrow it down? New noises?

You should also pull each of your spark plugs and check to see if it's showing signs of rich running. If it's not obvious, take some pictures and somebody can hopefully point you in the right direction.

 

[JamesR]

The fuel was slightly lower than the middle.
Smells like it's running rich all of the time it's running.
I'll check the plugs.
Thanks.

 

[GeologistFelix]

I think we can rule out a fuel bowl/float problem until we get more info -- it's kind of a pain to dig into the carb, so it pays to check what you can and get as much info as possible before opening that can of worms. Good luck!

 

[JamesR]

I totally agree - a have more worms than I can handle...almost. I certainly don't want/need more.

 

[Michaelinlv]

The catalytic converter is still there. Is there a way to check that without removing it and replacing it with a section of exhaust pipe? I don't mind doing the work; I would prefer not to if it's not going to change anything.
I appreciate your input.

Go to the exhaust, with the engine running you should be able to feel the "pulse" of each cylinder firing. If its a solid flow of exhaust gases then Id think it's a clogged Catalytic converter

 

[Seth S]

Have you looked at or replaced your plugs recently?