About a month ago I had the radiator hoses and water pump replaced on my '84 Z-28. It is not my everyday driver. In the few times I have driven it since I get quite a bit of smoke out of the pipes when I start it and also black soot on the ground under each of the pipes (see attached picture). Also, when I pull up to a stop sign it will sputter and die. It has progressively gotten worse and now it will die unless I shift it into neutral and rev it. Once it gets going it seems to drive fine. Can anyone give me some direction on what the problem may be? I only mention the new hoses and water pump because this problem began right when I had that done - it could be a total coincidence. Thanks for the help.

 

It's running very rich. Coincedense with water pump replacement. Might be an ignition issue, timing issue, or fuel issue - is it a carbed car?

 

It is carbed. Is that the likely problem?

 

I'm certainly no expert on the Quad carbs - but you need to figure out why it's running so rich. Could be a bad O2 sensor, TPS, IAC, ignition issue, timing issue, or a slew of other things I'm no expert on. I'm sure someone with more knowledge on these systems will chime in.

 

is the black substance sludgy at all. Judgin by the picture it looks like unburnt fuel, when is the last time the engine has had a full tuneup? might be a good time to do it.

if it is indeed your carb its probably the choke circuit, the float is stuck or has filled with gas from age and doesnt float anymore.

 

It is not sludgy at all. It is more like a fine powder. If I stick my hand at the end of the tailpipe it doesn't get damp at all - it just gets this black sooty powder on it. And I should probably add that when it is "chugging" right before it dies the choke light is coming on and off.

 

Bringing this post back from the dead - - -

I have this issue with my 86 IROC 305 TPI. What ended up being the issue and the fix?