Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Jeep > General Discussion
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 12-07-2009, 10:55 PM   #1
DaveShooks
AF Newbie
 
Join Date: Dec 2009
Location: Battle Creek, Michigan
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Question 86 CJ7 Guzzles gas while idleing

My 86 CJ7 with a 258 will go through a gallon of gas in around 3 minutes while idling. It's been a long process to get it to even start again, and now that it does it goes through gas like crazy. Is this an expensive fix? I do have a carb rebuild kit (2 barrel Carter)on the way for it as I know it needs that. What else could it be? Any help would be greatly appreciated.
DaveShooks is offline   Reply With Quote
Old 12-08-2009, 08:25 AM   #2
denisond3
AF Enthusiast
 
Join Date: Mar 2007
Location: VA in summer, TX in winter, Virginia
Posts: 1,323
Thanks: 2
Thanked 13 Times in 13 Posts
Re: 86 CJ7 Guzzles gas while idleing

I dont have a carbureted Jeep, (its an 86 Commanche with TBI) but anything with a carb is likely to need a rebuild on its carb every 10 to 15 years. If this will be the first rebuild for that carb, its certainly due. And for any engine with a carb, there isnt any other way for it to guzzle gas at an idle other than via a defective carb. It cold be a stuck float or one that has slowly filled with gas, or crud that is blocking the needle valve in the float chamber from filling, or....
I would presume the spark plugs are very black, even looking wet - and its hard to start because the idle mixture is too rich, and the plugs get fouled and then wont fire.
Be sure to have a good gasket at the base of the carb. I dont know about the 2 barrel ones, but on many 4 barrel carbs, there are vacuum passages that run along the bottom of the carb, and if the bottom gasket is ripped/shrunk/torn, the passage is opened up; and may be dribbling fuel into the intake manifold directly, instead of through the idle jets.
If the fuel pump is more than 10 years old, it might be a good time to change that too. I had a mechanical fuel pump whose little rubber diaphram began to disintegrate, feeding tiny rubber bits up to the carb - where they cause the needle valve to stick slightly open: And the engine would barely run due to being over-rich. Black smoke was visible from the exhaust pipe.

I have a 37 year old motorhome, and because it typically sits for 11-1/2 months each year, the carburetor gaskets shrink up and require replacement about every 6 or 7 years!
denisond3 is offline   Reply With Quote
Old 12-10-2009, 08:10 PM   #3
fredjacksonsan
Caution: Monkeys bite!
 
fredjacksonsan's Avatar
 
Join Date: Apr 2004
Location: near Denver, Colorado
Posts: 10,109
Thanks: 14
Thanked 67 Times in 62 Posts
Send a message via AIM to fredjacksonsan
Re: 86 CJ7 Guzzles gas while idleing

A gallon in 3 minutes.... !!

I'd say there is a leak in the fuel system somewhere. If you're driving normally, does it use less?

If it's running THAT rich, then there will be a wet deposit on the inside of your tailpipe.
__________________
Ours: 2020 Jeep Wrangler 2.0, 53k
2013 Toyota FJ Cruiser, 84k
Kids: 2005 Honda CRV, 228k
fredjacksonsan is offline   Reply With Quote
Old 12-12-2009, 05:13 PM   #4
rhandwor
AF Enthusiast
 
Join Date: Sep 2006
Location: Athens, Georgia
Posts: 4,662
Thanks: 0
Thanked 64 Times in 64 Posts
Re: 86 CJ7 Guzzles gas while idleing

Use a vacuum pump and check all choke pull offs. Make sure the choke opens when warm. As previously mentioned put the vehicle on jack stands. Use a flashlight and look over the fuel tank and follow the gas line to the carburetor. Fuel pumps also will leak when going bad.
Carburetor cleaner isn't as good as it used to be boil in an old pan after dismantled with plastic or rubber parts removed. Use a rolling boil for 20 minutes.
Put the float in your hand and shake if you feel liquid replace with a new one.
Napa should carry all parts needed.
rhandwor is offline   Reply With Quote
Old 12-20-2009, 05:51 AM   #5
fredjacksonsan
Caution: Monkeys bite!
 
fredjacksonsan's Avatar
 
Join Date: Apr 2004
Location: near Denver, Colorado
Posts: 10,109
Thanks: 14
Thanked 67 Times in 62 Posts
Send a message via AIM to fredjacksonsan
Re: 86 CJ7 Guzzles gas while idleing

So, how's the situation?
__________________
Ours: 2020 Jeep Wrangler 2.0, 53k
2013 Toyota FJ Cruiser, 84k
Kids: 2005 Honda CRV, 228k
fredjacksonsan is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Tags
1986 , carb , cj7 , jeep
Go Back   Automotive Forums .com Car Chat > Jeep > General Discussion

Thread Tools

Posting Rules
You may not post new threads
You may not 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



All times are GMT -5. The time now is 05:39 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts