Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Sputtering and black soot out of tailpipes

Old 05-18-2011, 02:59 PM
  #1  
Junior Member
Thread Starter
 
3-Ball's Avatar
 
Join Date: Feb 2010
Location: Overland Park, Kansas
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Car: 1984 Z28
Engine: 305
Transmission: auto
Sputtering and black soot out of tailpipes

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.
Attached Thumbnails Sputtering and black soot out of tailpipes-img00301-exhaust.jpg  
Old 05-18-2011, 09:17 PM
  #2  
Supreme Member

 
camaronewbie's Avatar
 
Join Date: Sep 2002
Location: Cary, North Carolina
Posts: 9,192
Likes: 0
Received 16 Likes on 16 Posts
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Sputtering and black soot out of tailpipes

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?
Old 05-19-2011, 01:00 PM
  #3  
Junior Member
Thread Starter
 
3-Ball's Avatar
 
Join Date: Feb 2010
Location: Overland Park, Kansas
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Car: 1984 Z28
Engine: 305
Transmission: auto
Re: Sputtering and black soot out of tailpipes

It is carbed. Is that the likely problem?
Old 05-19-2011, 07:02 PM
  #4  
Supreme Member

 
camaronewbie's Avatar
 
Join Date: Sep 2002
Location: Cary, North Carolina
Posts: 9,192
Likes: 0
Received 16 Likes on 16 Posts
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Sputtering and black soot out of tailpipes

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.
Old 05-19-2011, 07:15 PM
  #5  
Member
 
jkrustchinsky's Avatar
 
Join Date: Mar 2009
Location: San Antonio Texas
Posts: 130
Likes: 0
Received 0 Likes on 0 Posts
Car: 1982 Trans Am, 1986 Gmc sierra
Transmission: 700r4
Re: Sputtering and black soot out of tailpipes

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.
Old 05-20-2011, 09:13 AM
  #6  
Junior Member
Thread Starter
 
3-Ball's Avatar
 
Join Date: Feb 2010
Location: Overland Park, Kansas
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Car: 1984 Z28
Engine: 305
Transmission: auto
Re: Sputtering and black soot out of tailpipes

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.

Last edited by 3-Ball; 05-20-2011 at 09:17 AM.
Old 06-02-2016, 06:59 PM
  #7  
Junior Member
iTrader: (1)
 
KI4FKW's Avatar
 
Join Date: Jul 2012
Location: Alabama
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Car: 1986 IROC-Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.23
Re: Sputtering and black soot out of tailpipes

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?
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
db057
TBI
14
04-28-2019 07:45 AM
WickedBowtie
Members Camaros
10
09-17-2015 09:13 AM
Saxondale
History / Originality
6
09-15-2015 06:42 PM
WickedBowtie
Interior
4
09-11-2015 11:24 PM
Stroopwafel
Tech / General Engine
7
09-11-2015 06:38 AM


Thread Tools
Search this Thread
Quick Reply: Sputtering and black soot out of tailpipes



All times are GMT -5. The time now is 08:47 PM.