Hello... My buddy and I rebuilt my pickup over a year ago. ALL new parts from LC Engineering. Had the 5 speed manual tranny rebuilt. New leaf springs and shocks, Kellys machine shop punched it out .10 over, rebuilt the head, New 38D gas carb, intake, pistons, crank, oil pump, fly wheel. headers, fuel filter, mechanical fuel pump, deleted EGR valve and smog pump with block plates on the head and block. I have been trying to get it right for over a year now and cant figure out WTF is wrong. And it is getting worse and worse. When it's backed in the driveway it starts right up from Phoenix Az cold and it idles decent but not great. Take ebrake off and let it roll into the street, when it levels out (WITHOUT TOUCHNG THE BRAKE, no vacuum leak) the idle goes up slightly. Start driving it, the slower I slow down the slower the idle comes down. If I stop real fast it just dies and takes a few extra cranks to start. Trying to drive it, for the most part, it just spudders and spits. It's almost like it's losing fuel. The LC Engineering guage is set right between 2 and 3 psi. As it's supposed to be. Since there seems to be a gravity issue and EVERYTHING is new, the only thing I can think of is there is something wrong with the tank, or in the tank, like the fuel pickup line is cracked or broken in the tank and when the gas sloshes around it moves the line around, opens the crack and it loses suction somehow, or one or some or all the louvers are broken and the gas sloshes around and loses suction. PLEASE HELP. I spent a S#!# ton of money on it and I am at my wits end and don't know what else to do/try except f'n with the tank. THANK YOU!!!

 

Check the float level adjustment in your carb.
does it also die if you are sitting still and stab the brakes?

 

I forgot to mention, I also replaced the plastic float with a brass one. Nothing changed. Pressing the brake makes no changes at all. No vacuum leak.

 

But did you adjust the float level? Properly? Too high will make it flood out, too low will make it starve for fuel.

 

I think so, but, as I said in the first post. The idle goes up and down depending on it being backed in the driveway (on a decline) seems good or flat on the street it it goes up about 300 rpms or so. Slowing down slowly the idle comes down slowly and stoping quickly makes it die. Would that have anything to do with the float?

 

Yes, it could. under breaking fuel is likely sloshing out of the bowl through the vent and flooding your engine. that is why it is hard to start afterwards. It does it a little when you're on an incline and a lot when you are breaking.
if your pickup tube in the tank was cracked or broken your problem would not occur with a full tank, only at lower levels and once it was low enough it wouldn't run at all.

 

Great!!! Thank you very much for the explanation! I will check the float and see what happens. Again thank you for your time!

 

Just wondering if you ever solved the problem with your carburetor? I did a similar rebuild on my '85 22r and was similarly frustrated with the results. Was it the float? I'm wondering because before the rebuild, I tried to address some vacuum leaks in the fuel system which is what eventually led to the rebuild.

 

Believe it or not, the power break booster had a MAJOR internal vacuum leak. It is supposed to hold 10 psi or so and it was only holding 2 or 3. Replaced it and my truck runs like a champion now. If that thing gets the least little vacuum leak it is going to make the vehicle run terrible until it's replaced.

 

Thanks for the quick reply. This info might prove useful to me. I'm checking it out now...

 

I hope so. I've owned this truck for 18 years now. That SAME thing happened to me about 10 years ago. That time my truck was running bad for a long time. The power brake booster went completely bad where the power brakes didn't work. I Replaced it the power brakes fixed AND my truck ran great. I just didn't think about that until the mechanic that was working on my truck this time figured it out. SO FRUSTRATING. I have to remember for next time. Please let me know if that works for you.