The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-23-2013, 11:55 AM   #1
FLDBRED
Registered User
 
Join Date: Jun 2009
Location: CENTRAL,NJ
Posts: 586
Bad Gas???

Ive been rebuilding my truck for the last couple of years. Ive been adding gas on ocasion with a gas can, but I have never run the gas completely down. My progress has me at the point where I would like to actually drive the truck. Problem is, truck strarts but shuts off as soon as you touch the gas. Could it be bad gas? What's the best way to remove the old gas or should I just throw some Lucas in there and let it run down?
FLDBRED is offline   Reply With Quote
Old 06-23-2013, 12:34 PM   #2
68gmsee
Active Member
 
68gmsee's Avatar
 
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
Re: Bad Gas???

I'm assuming you can crank it and it will idle okay but die when depressing the gas pedal to increase rpm's. If that's the case, it could be several things:
carburetor accelerator pump not working, float adjustment off, flooding or internally clogged carb passages, vacuum leak, vacuum advance not working properly and ignition timing or points adjustment if you have them.

Eliminate them one by one with easiest first but if you want to eliminate gas as the problem, get a one gallon container of fresh gas and go to auto parts and buy a piece of fuel line the same size as the one that goes to the fuel pump. Place the fuel container under the truck and under fuel pump with new hose going to the fuel pump and to the container.
__________________
68 GMC 250/3 speed Saginaw p/b p/s
69 Chevy 350/350 currently in pieces still lookin for a cab
06 Trailblazer
I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...
68gmsee is offline   Reply With Quote
Old 06-23-2013, 12:44 PM   #3
sprint_9
Registered User
 
sprint_9's Avatar
 
Join Date: Nov 2012
Location: 9
Posts: 862
Re: Bad Gas???

Have you checked/changed the fuel filter?
sprint_9 is offline   Reply With Quote
Old 06-23-2013, 01:13 PM   #4
FLDBRED
Registered User
 
Join Date: Jun 2009
Location: CENTRAL,NJ
Posts: 586
Re: Bad Gas???

Thanks for the tips guys! I had the same problem when I first brought the truck home, but didn't worry about it because I knew I was going to change the intake and carb. After changing the intake and carb, the problem is still there. The truck starts, idles down, seems to run ok, but if you even slighty touch the gas it shuts off! I'll try the gas container idea, thanks!
FLDBRED is offline   Reply With Quote
Old 06-23-2013, 02:36 PM   #5
68gmsee
Active Member
 
68gmsee's Avatar
 
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
Re: Bad Gas???

HEi or points distributor? Have you double checked the timing?

Since you have replaced the carb be sure and also check the vacuum advance for leaks or not working and for any other possible vacuum leaks. If you have a brake booster disconnect it and plug the hose and even modulator lines if you have a 350 tranny. Basically eliminate any possibility of vacuum leaks.

Last but not least, make sure the fuel pump will pump at least a pint of gas into a plastic container in less than 30 seconds, put a meter across the battery posts while it's idling and insure you have app. 13+ vdc. If you have an HEI, check that it's getting a full 12vdc and you're not using original wire from firewall which is resistive.
__________________
68 GMC 250/3 speed Saginaw p/b p/s
69 Chevy 350/350 currently in pieces still lookin for a cab
06 Trailblazer
I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...
68gmsee is offline   Reply With Quote
Old 06-23-2013, 04:25 PM   #6
FLDBRED
Registered User
 
Join Date: Jun 2009
Location: CENTRAL,NJ
Posts: 586
Re: Bad Gas???

Great advice, with this type of help I know I'll get to the bottom of this! Thanks!
FLDBRED is offline   Reply With Quote
Old 06-23-2013, 04:32 PM   #7
TBONE1964
Cluster King
 
TBONE1964's Avatar
 
Join Date: Nov 2012
Location: Junction City, OR
Posts: 5,263
Re: Bad Gas???

If it has bad gas, you will smell it. It has an odor like nothing else you have ever smelled. If the truck even starts then your problem is probably not from bad gas. Bad gas gets thick and will not even burn.
TBONE1964 is offline   Reply With Quote
Old 06-30-2013, 05:15 PM   #8
elf w/capital T
Registered User
 
Join Date: Feb 2011
Location: North Carolina
Posts: 994
Re: Bad Gas???

Thanks for the update!!
elf w/capital T is offline   Reply With Quote
Reply

Bookmarks


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

Forum Jump


All times are GMT -4. The time now is 12:37 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com