It's to the point that I could pour gas on the ground and get better mileage. I drove 6 miles (usually 1 gallon of gas) today and used over an 1/8th of a tank. Thats also granny driving it and holding a constant 55 mph. Usually I get about 6-7 mpg. However, now that the heat has risen to about 105* outside and humid, my gas mileage has dropped to almost 1.5 gallons PER MILE. Prior to this I was battling fuel boiling issues and weird "no spark" issues. There are the new parts that have been installed:

-fuel pump
-distributor
-insulated fuel lines
-carb 1/2" spacer (carb is now 1" off the intake)
-coil
-ignition module
-choke (manual to electric)

Currently the truck is getting spark (verified with a screwdriver) and is getting gas and doesnt seem to have the extreme heat soak issue the led to the boiling gas. However, now these are my current issues:

-the truck starts hard when hot and cold. Sounds like its got no gas in it. In order to start it (it cranks fine), I have to stomp the pedal 3 times then hold the pedal 1/3 of the down and crank it and then it will start.
-when really hot the truck starts as if the timing is too far advanced (it cranks realllllllllly slowly and then finally starts)
- the truck heats up super quickly when idling.
- the truck loses large amounts of power when hot and takes forever to take off from a stop sign (it has to idle up like a diesel before it will move)
- the tranny shifts slowly too. It acts like I'm towing a frickin trailer.

Are these issues related to the excess heat under the hood? I'm well over 400* even when freeway driving. I'm getting a 460 radiator on saturday with limited miles on it and its a 4 core too for $200. I'm also going to get a new thermostat and maybe new coolant (the coolant is already pretty new and is still good though). The fan clutch is good. You can hear it spool up and drop down when the rpms of the engine change.

Any chance that fixing the radiator and the heat issue will resolve most if not all of these issues?

 

That's going to flood any engine.

That has to be a typo, right?

It sounds like you have a lot of systematic issues that need to be resolved first; the poor gas mileage is likely a result of a combination of these issues. How long since the carburetor was last gone through? What's the vacuum gauge say?

 

Carb was redone a month before I got it (the float still looks newer, etc.) the vaccuum gauge shows a perfect 20 with the engine idling. No the 400* isnt a typo. I verified it at the intake this afternoon with an infrared thermometer.

 

That's what I thought? Lol I got scared when my ranchero hit 220 and shut it off for a while. Is there fluid movement? Take off radiator cap and start it and see of the fluid is moving? Check water pump? That's what was wrong with my 351. I know its a big diff but its worth a shot and its a cheaper fix to try/test. Not gunna help your other issues prolly but that heats not good.

 

fluid is moving and the water pump is good. Ok maybe the 400 is incorrect. I'm checking it now with my temp gun (first I used my dads) and am seeing about 260ish*.

Sheesh his thermometer really must be off then. haha sorry for the scare guys it worried me too.

 

does it pop,spit, hiccup or make any noises doing this?
does it diesel after shutting it off?

 

For the trans shifting, have you checked the fluid lately? I had noticed it leaked a bit when I had it, because some idiot before me did a bad job of putting in a tranny drain plug.

My father and I rebuilt the carb with a genuine rebuild kit... I actually just found the old box from that. So the carb should be good. However, has anything been done to the starter? When I had it, the starter was beginning to have issues of the gear not disengaging and it would drag for a short time. I meant to look at it, but forgot. Anyway, I had just thought maybe there was a starter issue as well.

 

The tranny fluid is full I just topped it off. As for the starter, thank for the heads up I'll check in to that.

@dustyroad: when the trunk get really hot it will vibrate really badly and will start to almost hop up and down when its idling in gear. It doesnt backfire either. The engine doesn't diesel either. It just shut off normally.

 

Are you loosing any coolant ? If not it may not be getting as hot as you think . Have you checked the timing ? Is the timing chain and sprockets in good condition ? Timing can be way off and still run and i'v had them run hot when it's way off to the retard side.

 

Nope all the coolant is there. The timing is now set dead on using a light (I had a shop do it).

 

Sounds to me like you are running way rich. That could also account for running hot.

 

Yep , I would second that if the timing is good, that could be the reason it's slurping up the fuel .

 

I think you guys mean lean. Running lean (as the OP has to be) = worse gas mileage than rich and a hot motor.

If he was rich enough to be getting 1.5 gallons per mile he'd have black smoke pouring out that tailpipe. I'd check fuel pressure and flow, for vacuum leaks then check out the carb.

 

Pull the distributer cap off and un plug the vacuum line for the distributor at the carb side, suck on the hose and see if your mechanical plate in the distributor advances, if not you need a new distributor vacuum pot (The part the hose connects to on the dist) if it doesn't move and you can suck thru it like a straw it's bad! It's not advancing the timing as you accelerate causing at least some of your issues.

Also check your plug wires and make sure they are in the right firing order, if you have a plug wire crossed to the wrong plug it would cause all the issues you mention. Hope this helps!

 

The wires are in the right order. I put them on using my shop manual.

The vaccuum pot is good. I checked it and it flaps back and forth while sucking the hose. It is also new because I got it on the new distributor.

Running lean may be a viable option, but I'm thinking its my radiator thats messed because its the same temp at the top and the bottom of the radiator. Shouldn't the radiator be hotter on top and cooler on the bottom?