Solution to 8.8mpg??? - Off-Road Forums & Discussion Groups
GM Standard SFA Trucks & SUV's All discussion of full sized Solid Front Axle Trucks, SUV's to include Suburban

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 08-21-2002, 07:53 PM Thread Starter
 
Join Date: Mar 2001
Posts: 766
Thanks: 0
Thanked 0 Times in 0 Posts
 
Solution to 8.8mpg???

Okay, on sunday I am driving 1600km back home and I've been getting less than 9 mpg with a motor with 5000km on it.

When I'm under load (i.e. lugging up a hill in 4th) I smell gas. I have the timing set good, and the idle mixture and speed set.

Is my problem internal to the carb?? or is there any way I can somewhat fix this for better millage on the way home??

Any ideas? I don't have the time or skill to be trying out new jets and whatnot, and I'm not gonna buy a new carb up here.

Thanks for any ideas.

It cost me 18 bucks to drive 60 miles last night, so anything is helpful.
beaterchevy is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 08-21-2002, 08:12 PM
 
Join Date: Jul 2001
Posts: 543
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Solution to 8.8mpg???

any leaky fuel lines? I had one I couldnt see on my 72, but I replaced the line on a hunch and doubled my milage from 6 to 12!
ben427 is offline  
post #3 of (permalink) Old 08-21-2002, 08:52 PM
87sm465np208
Guest
 
Posts: n/a
Re: Solution to 8.8mpg???

hey man, your truck kicks [censored], i totally dig that multi colored body, and your combo SM465\NP205\d44\14ff that kicks even more [censored], how did you come across your rig?
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 08-21-2002, 11:26 PM Thread Starter
 
Join Date: Mar 2001
Posts: 766
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Solution to 8.8mpg???

Well, I'm pretty sure I'm not leaking fuel cause te only puddles under the truck (for now) are a bit of oil coming out either the rear main or the pan.

87 - thanks, it's just a beater but it's taken me lots of places. I found it in the local buy and sell, buddy wanted 1800 and I got it for a grand (canadian). Needed tranny mounts and new rear springs. Sure don't look like it but I've put tons of parts into the damn thing.

beaterchevy is offline  
post #5 of (permalink) Old 08-22-2002, 12:16 AM
 
Join Date: Nov 2001
Posts: 811
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Solution to 8.8mpg???

That's the thing with gas it evaporates so fast so you might not even see it, not to mention it might not be spewing gas unless the line has pressure in it.
pitviper is offline  
post #6 of (permalink) Old 08-22-2002, 08:51 AM
ratlover
Guest
 
Posts: n/a
Re: Solution to 8.8mpg???

what carb? your idel circiut might be set alright but the primaries and or secondaries might be running too rich. Hows the tune of the rest of the vehicle? plugs wires airfilter and such.
post #7 of (permalink) Old 08-22-2002, 09:01 AM
logan_ut
Guest
 
Posts: n/a
Re: Solution to 8.8mpg???

When your climbing a hill does is bog at all? If it is a 4 barrel are your secondaries open when you start to smell the gas? I had a similar problem in my '81 and my secondaries were running too rich and would cause the smell and a slight bog. It killed my mileage too.
post #8 of (permalink) Old 08-22-2002, 06:16 PM Thread Starter
 
Join Date: Mar 2001
Posts: 766
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Solution to 8.8mpg???

yeah, logan_ut that sounds like the problem. Its a 4barrel q-jet, and the secondaries would be open when I'm smelling the gas.

How'd you fix it?? Different secondary jets?? I know nothing about the internals of carbs.

If I unplug my vacuum secondaries will this *fix* the problem till I get home???
beaterchevy is offline  
post #9 of (permalink) Old 08-22-2002, 06:55 PM
Carpal \'Tunnel
 
wrath's Avatar
 
Join Date: Nov 2001
Location: Waukesha, WI
Posts: 3,323
Thanks: 0
Thanked 1 Time in 1 Post
 
Re: Solution to 8.8mpg???

I'd just wire them shut and see if that fixes it.
wrath is offline  
post #10 of (permalink) Old 08-23-2002, 11:12 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Solution to 8.8mpg???

Does your carb cause a bog such as the secondaries opening too soon? Or do you merely smell fuel, which could be something different. You can tighten the spring that keeps the secondaries from opening too soon, but you need to probably have someone to show ya if you don't know how. It's not difficult, but you don't want to loosen anything without having a hold of it. The adjustment is made right behind the choke and in front of your vac advance. If you have a small mirror you might see that a allen head set screw holds the adjustment. Just look it over, I can't recall, it's been a long time since I messed with one. Passenger side of the secondary shaft. Some tend to loosen this up when discovering it in false hope of getting more power when in fact it usually creates a bog to have them open too soon. You can play with the tension a bit both ways and romp it to fine tune things, but need to have everything right before this step.
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user 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:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome