strong exhaust smell and smoke after idling??? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-08-2004, 11:57 AM
69elcaminoss's Avatar
Member
 
Last photo:
Join Date: Feb 2004
Location: Las Vegas
Posts: 115
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
strong exhaust smell and smoke after idling???

My brother just picked up a 1984 Chevy shortbed truck with a 305 and 4 barrel carb. The truck is completely stock.

The problem is after idling for 5 minutes or so their is some greyish looking smoke coming out of the tail pipe. When you rev up the engine it goes away after a minute. Also, there is a strong exhaust smell when idling.

What has been done to this point.....
new air filter
new fuel filter
new spark plugs
sprayed a bunch of carb cleaner down the carb while running
put in a bottle of fuel system cleaner

The condition has improved greatly but has not gone away at this point.

All of the vacuum lines appear to be connected except the "thermostatic vacuum switch" which is on the thermostat has one nipple broken off of it and the vaccum line has been plugged with a screw that leads to the distributor. Could that be causing the problem????

Sorry for the long post, this is driving us crazy!!!!

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-08-2004, 12:19 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,932
Wiki Edits: 0

Thanks: 13
Thanked 47 Times in 36 Posts
Sounds like its running extreemely rich. Does the truck have cats on it? If so, they may be partially plugged and beginning to overheat and smoke out the pipe.

Is it a feedback Qjet? or regular Qjet?

With it idling, look down the carb and see if you see any gas dripping from the nozzles. Could be a bad needle and seat or a bad/sinking float or the float level is too high. May be time to go through the carb and install a new float while you're at it.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-08-2004, 12:26 PM
69elcaminoss's Avatar
Member
 
Last photo:
Join Date: Feb 2004
Location: Las Vegas
Posts: 115
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally posted by Jmark
Sounds like its running extreemely rich. Does the truck have cats on it? If so, they may be partially plugged and beginning to overheat and smoke out the pipe.

Is it a feedback Qjet? or regular Qjet?

With it idling, look down the carb and see if you see any gas dripping from the nozzles. Could be a bad needle and seat or a bad/sinking float or the float level is too high. May be time to go through the carb and install a new float while you're at it.

Ok, how do I tell if it is a feedback Qjet or a regular???
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-08-2004, 12:49 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,932
Wiki Edits: 0

Thanks: 13
Thanked 47 Times in 36 Posts
If its the original truck carb, its probably not, but thought I'd ask.

the feecback carb will have a throttle position sensor in it, it will have a plug sticking out the front on the drivers side with 3 (?) wires comming out. There will also be a large bump on the top front left with 2 wires on it.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-08-2004, 01:21 PM
killerformula's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 34
Posts: 3,487
Wiki Edits: 3

Thanks: 13
Thanked 27 Times in 18 Posts
almost sounds like the bowls are leaking into the carb and the engine is loading up with fuel. COuld be a choke pull-off too.

K
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-08-2004, 03:38 PM
69elcaminoss's Avatar
Member
 
Last photo:
Join Date: Feb 2004
Location: Las Vegas
Posts: 115
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally posted by Jmark
If its the original truck carb, its probably not, but thought I'd ask.

the feecback carb will have a throttle position sensor in it, it will have a plug sticking out the front on the drivers side with 3 (?) wires comming out. There will also be a large bump on the top front left with 2 wires on it.

It doesn't have any of that stuff so I assume it's not a feedback carb.

Killer formula, what would I need to do to fix that problem than?? Have the carb rebuilt or is it something I could do at home.

As a side note: That truck has so many vacccum lines going all over the place. Half the lines were rotten going to the smog stuff from the thermostat so I just ran a vacuum line straight from the distributor to the carb and bi passed all the smog vacuum stuff. That made it idle a little better.

This is getting frustrating.......
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-08-2004, 04:12 PM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,932
Wiki Edits: 0

Thanks: 13
Thanked 47 Times in 36 Posts
If its the original GM QuadraJet carb and you aren't familar with rebuilding them, i'd suggest finding someone to help. Do NOT buy a remanufactured carb from the stores, they rarely work right and even more rarely have the correct jets and metering rods for the original application.

It might be to your advantage to find a good shop to put the truck on the scope and check it out. They can also check the exhaust emissions to see if it is in fact the carb causing the problems. It will be 40 or so dollars well spent. Been there, done that.

Mark
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 03:32 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.