14 mpg guzzler

bandit · Post by **bandit** » Tue Aug 01, 2006 2:34 pm

you can try unplugging the cold start valve to see what happens
to your mileage then easy enough to do .

Dan

Mark_vaughn · Post by **Mark_vaughn** » Tue Sep 12, 2006 9:44 am

How do you test this cold start valve? I am getting about 15mpg on a stock engine. Seems a little low.

So Cal Mark · Post by **So Cal Mark** » Tue Sep 12, 2006 10:22 am

cold start valves are only on FI engines, beginning in 1980

TVST*R · Post by **TVST*R** » Tue Sep 12, 2006 11:09 am

Mark_vaughn wrote:How do you test this cold start valve? I am getting about 15mpg on a stock engine. Seems a little low.

That is extremely low mpg. Mine went from 14mpg to 19mpg thanks
to SoCalMark and his great Carb work.
T

Mark_vaughn · Post by **Mark_vaughn** » Tue Sep 12, 2006 11:16 am

Could the automatic choke affect my milage? The car runs fine, starts without much trouble when cold, and starts right up when warm. It appears to be the original carb. The idle is set a little high, but I wouldn't think that would be a big deal. Any thoughts?
Sorry Mark, too far from CA to stop by. Wish I could, nobody will touch it around here.

So Cal Mark · Post by **So Cal Mark** » Tue Sep 12, 2006 11:38 am

if the choke doesn't open fully it will have a huge effect on fuel mileage. A common problem on the late 70s models are corroded water tubes to the choke. Warm the car up, remove the air cleaner lid and see if the choke is completely open. If not, feel the two water hoses going to the choke. More than likely they won't be hot. Then you'll need to remove the hoses and unplug the nipples that the hoses attach to.
If the choke is open, you'll need to check the carb out. Look for leaks from the accel pump housing. You could also have a float set incorrectly or wrong jets in the carb

Mark_vaughn · Post by **Mark_vaughn** » Tue Sep 12, 2006 12:07 pm

Thanks Mark.

I will give it a try this evening.

Mark_vaughn · Post by **Mark_vaughn** » Wed Sep 13, 2006 12:54 pm

Choke works. While I was messing with it I noticed a small gas leak. Not even enough to drip, but maybe over a few hours or with higher pressure at speed it could be more. I don't know if it is enough to make a difference in mpg or not but I will fix it and see.

Any other thoughts?

So Cal Mark · Post by **So Cal Mark** » Wed Sep 13, 2006 1:56 pm

any leak will affect mpg. Is the exhaust black, or do you notice a strong exhaust smell? Have you looked at the spark plug tip for signs of a rich mixture?

Mark_vaughn · Post by **Mark_vaughn** » Wed Sep 13, 2006 2:12 pm

The exhaust is normal, no strange colors or odors to it. What am I looking for on the spark plugs? I haven't removed them yet, probably need replacing anyway.

So Cal Mark · Post by **So Cal Mark** » Wed Sep 13, 2006 3:25 pm

you're going to look at the color of the plug tip; if it's black and sooty then you have an overly rich mixture. It should be a nice brown color if the mixture is right

Mark_vaughn · Post by **Mark_vaughn** » Wed Sep 13, 2006 7:42 pm

I haven't checked the plugs yet, but changed the fuel filter and a few hoses and clamps that were leaky and found the source of my leak. The part of the carb that sticks up a little and the fuel hoses go in and out is leaking. I can't tell exactly where, I think maybe the return (top) plug. It spins like it is floating in there, not screwed in.

Has anyone messed with these carbs much. It is a 32adaf I think, the basic one that came on the '77 model. Can I get a gasket or something and just rebuild that one part, or is the whole thing going to have to come apart?

So Cal Mark · Post by **So Cal Mark** » Thu Sep 14, 2006 1:06 am

it's common to find the inlet and return nipples loose and leaking. Use a brass hammer to tap them in to seat them. Best fix is to use a screw-in fitting to replace the press in fittings. Gasket kits used to be available for those carbs, but I would expect you'll have trouble finding anything except a rebuild kit

124cso · Post by **124cso** » Thu Oct 26, 2006 7:39 pm

Looks like I got you all beat ? Recently did a 220 mile trip on open country highways. filled the tank to top of filler spout before & after and got 34 miles per imp gallon ( or 7.55km per litre) in my injected 2000.
Most of the way, I sat at between 60 & 70mph. The grade of fuel you use does make a difference too !

So Cal Mark · Post by **So Cal Mark** » Thu Oct 26, 2006 9:48 pm

here in Calif, our emission formulated fuel gets about 10% less mileage than fuel from other states

Using a fuel with higher octane than needed will make less power, not sure about fuel mileage