New member with fuel delivery problem

[Thomasbuilt]

Hey guys I'm new to the forum. I have included a picture of my truck. This is the only picture I had in new phone. Going to give you guys some extra info to help save some posts and time on figuring out my issue here.

Rebuild kit on carb
New Mechanical Fuel Pump-2,000 miles ago
New Tank and Pick up Tube
New Can Filter under truck
New In-line filter before carb

My grandpa passed away, and I luckly recieved this truck in its current condition. My grandpa had 3 GMC show trucks, 1953,1962 and 1971. I received the 1962. It had white walls, and very grandpa looking; but still a awesome truck. I put new chrome here and there inside and out, and some wheels I know my grandpa would not apporve of. But I still have the white walls to put on it from time to time. Thats my truck story and I'm truly bless to have a truck this nice at 36 years old.

When I got the truck; it had sat for 10 months due to his health. The carb had leaks from the gaskets and the fuel delivery was weak I assume because I was having trouble getting fuel to carb. I put a carb kit on, and a new fuel pump with life time warranty. I drove the truck around 1,500 miles with no issues for last 2 years but the last 3 month I have had fuel issues again. I know it was fuel issues because of the way it was running and cutting out. I know my way around engines a little, and alot about carbs and electrical systems. I dirt track raced for 7 years, and built my own chassis and machine parts. So I'm a little handy around the shop. But I started buying easy fix things that could cause a issue with fuel delivery as listed above. Still having issues. This is whats left to do: Get another mechanical fuel pump?, cam lobe could be worn and not enough stroke on fuel pump for proper suction? Or my ideal was to get a low pressure electric fuel pump (maybe 3lbs) right after the can filter under the truck where I could suck fuel coming down at it lowest point and pushing it to the carb and blocking off the mechanical fuel pump on engine? I thought maybe the stock fuel pump being so far way and maybe a wore cam lobe would cause it not to suck fuel properly and get air locked. Is this a good ideal? Any info would be great. Thank you for your help.

[Funky61]

Welcome Thomasbuilt!

Nice piece of family history you have there.

Which V6 engine and carb do you have? Either way I'd put a fuel pressure gauge on it to see what's happening there. Photos of what's cooking under the hood may help. Ignition coils can heat up and funny as well.

What kind of symptoms are you experiencing?

I had issues with mechanical fuel pumps; maybe because they were old stock and had sat on the shelf too long. I went electric FP.

[Ed Snyder]

Welcome to the forum, Thomas! That's a great looking truck your grandpa left you! I hope you keep the V6 in it and not swap it for a boring small block Chevy. I'm sure with the help of fellow forum members you'll get your fuel delivery issue sorted out.

When you said your grandpa would not approve of the wheels you installed, I can identify with that comment. I realize I'm probably showing my age (not to mention being a grandpa myself), but I don't care for what I call "rubber band" tires -- those with extremely low profiles. Our 2011 Subaru Forester came with 55 series tires, and I don't even really care for those. I went so far as to install my favorite size for our GMC trucks (235/85-16) on my 2005 Nissan Frontier pickup. I love seeing lots of blackwall showing!

Our son's new Nissan 370Z has P245/40R19 front and P275/35R19 rear tires and I'll have to admit they look pretty good on a sports car like that. But I'll take a good riding tire over a high cornering-capacity tire for our trucks any day.

Having said all that, more power to you! It's your truck and you should do whatever you want with it.

[BarryGMC]

Is it stalling.? Or stumbling when you accelerate? Is it hard to start? BTW Welcome to the forum. Barry

[jrmunn]

Thomas - After 36 years (your age?) of driving my 1964 GMC 1500 that came from my father, I can report that fuel pumps do go bad, and some "new" fuel pumps seem to have been sitting on a shelf for years while their diaphragms are aging (sort of like what seems to have happened in my back). But another possibility that caused me to make nearly all of the changes you describe, because I thought it was fuel related (hard starting, loss of power, intermittent running), turned out to be failing points. Good luck! With regular maintenance and some rust prevention/repair attention, these trucks really do keep on working. Also, just driving the truck has not taught me much about how to fix it, but others in this forum are very knowledgeable and have been very helpful when I needed it.

jrmunn

[Thomasbuilt]

Hey guys thanks for the input, this may be another long post, but I assure you not all my post will be so long.

Just so you guys know. I have been really busy working in the Natural Gas field last 4 months, plus I build houses on the side. But this truck is not a garage queen. I use this sucker when I'm off work from time to time. I go to home depot and buy supplies to build privacy fence or whatever, I put a moving blanket in the bed and take measures to protect the truck. But I have no need for something if I'm not going to drive it or use it. Just the last couple times it burned me going to town. So I have not drove it in two months and thats the longest I have ever gone. Thats why I'm here trying to get input to save time and energy getting to the source of the issue.

I agree the tires are way too low profile, and I do miss the ride of the stock tires. I had a blow out on the front right side with the stock tires and luckly there was no damage to fender or truck. All the tires had great tread, they did not show signs of dry rot or cracks, but inside they were breaking down from being 10 years old kept in a garage. I had a matching spare I was able to use. I was going to buy all new tires with same 2" white wall, but I could not find them anywhere. So the only choice was 3/4" or the full white wall, which I was fine with full white wall. But it was gonig to cost me $850 to $1000 for new white walls. So thats when I come across the 20's that are on it. The older men over 60 tell me straight up they hate the wheels, and it would be much nicer with factory. I do agree some. By the way I know the hub caps are from a 80's model GMC jimmy or truck, my granpa I guess was too cheap to fine put the orginial ones one it. I wanted torque master wheels, which in my opinion; is one of the best looking wheels that look good on older hot rods and trucks. I got these wheels for $300 and I spent a month looking for used newer tires at many tire shops. Finally found some tires for $200 and the guy let me mount one to see if it would clear the inside of the back wheel from the bed, I only have a 1/2" between the bed and tire. I would of love to put a bigger tire on the truck. I liked the height of the truck with the tires that were on so, I took the 20" rims and found a tire size that was the same height as the other. I did not want the truck any higher off the ground. On a side note: my personal truck is a Z71, that I could also put those wheels on so thats why I bought them. By the way the Ford Truck in the back ground is my company truck not personal, Sorry we are GMC and Chevy family. My wife drives a Yukon as well.


I will never ever never put anything other than the 305 V6, that is what I get asked all the time by respectable truck people. Plus I care nothing about speed. I never drive the truck over 45 mph or ever get on the interstate. One day I would like to get another 1962 305D rebuilt on a stand for back up.

Information about the truck: It is a 1962 with a 305 V6 engine number (#305D170241) with the single port carb and oil bath breather. The truck has 102,000 orginial miles on it. I have paper work and maintance receipt dating back 30 years with mileage recorded when work was done. It was in great condition before it was restored. It has the torsion bar front in with coils in the back. Only thing after market is a under dash AC unit and hidden hitch reciever under rear bumper.

Lets get to the reason I posted this thread: By the way the truck always starts everytime no matter how long it sits with little effort. The last couple of times I drove the truck it died on me and both times it was wrong day and time for it to happen. So I was little frustrated with it and foggie on finding the issue. About 6 month into driving it after I got it. One day it just turn off like someone turn the key off going down the road. After 10 minutes later it started. It was a hot day around 95 degrees, but the engine was not over heated. So I took it home and check the wiring going to coil and distributor. I clean and lightly sand the contacts on the points and reset them. Drove it for a year with no issues. Well!, after reading some response made me think I may be dealing with two issue happening as same time. Sometime when I pull up to a light and get stopped and wait a few minutes. When it turns green I take off normal and after about 800 feet + it will start to spit and sputter. So I will start pumping the petal for the excelrator pump to kick in to refuel the carb and most of the time it works. So with that I'm thinking if the RPM's are not kept up I'm losing suction from my pump, and very well may need a new pump.

Then this issue: I drive it to town and run in to a store for 10 minutes come back out and it will not start every now and then. So I grab the carb cleaner behind the seat and shoot a decent amount in the carb. It starts and runs for until the cleaner burns off. I was trying to get it running to prime the fuel pump or whatever. But after thinking last night. Maybe the points are going bad and are gettting extra touchy with heat. So my thought is carb cleaner is little more flamable than gas, So lets say I have a weak spark and under compression with gas and it kills the spark, and with carb cleaner it has enough to ignite it?? I don't know forsure the BTU rating between carb cleaner and gasoline. But common sense I figured it was a little more flamable.

I would like to get one of those HEI distributors off ebay, so I can have a hotter spark and run a bigge gap on my spark plugs. Has anybody bought one of these or know if this is the best way to go. They cost $255.

Things I will do in the near future:
New Plugs, New Plug wires, all new bigger gauge wiring running to coil and distributor. Maybe new HEI distributor, after market air cleaner, do a compression test, and last INSTALL LAP SEAT BELTS, so I can take my kids for a ride. My wife will not allow my kids to ride in the truck without putting seat belts in it. Has anybody out there installed lap belts, I;m sure I will have to drill through the bottom of truck to attach these? Here are some pics when I first got it. Thank again for reading the extra long post and additonal information.

[BarryGMC]

The hot day shutdown sounds like a vapor lock. Today's gas has a lot lower boiling point, especially the cool weather blends with a lot more butane. This gas workes fine in a pressurized system with a return line but is somewhat problematic in a carb set up. I have a 58 chevy 348 car that is so sensitive to this when it's warm if there is any winter blend fuel in the tank, that I now run any gas out in the spring before it gets hot. The sputtering in my opinion is probably something in the carb that is randomly blocking a jet. I see this a lot. I have 11 pre 1972 vehicles with carbs and points ignitions. Rarely do I have an ignition issue. But carbs need constant attention. Barry

[BarryGMC]

One more thing don't change the wiring to the coil. This wire is a resistance wire if you change it the only thing you will accomplish is burning up a good coil.

[adamfgarner]

I bought and installed one of the HEI distributors from HEIDizzy on ebay...price then was $270...my truck runs great after I got my timing set...put new plugs, wires and the Holley carb...it starts quicker than my EFI vehicles...I am not a good enough mechanic to mess with point regularly so this worked for me...if you go HEI you will have to swap your distributor gear - mushrooming the new pin will be the hardest part...

My truck has seat belts (which I have tucked under the seat - I hate them!) and I would wager that yours is already drilled for them - have you looked?

[WDShaffer]

I am by no means a purist... I do appreciate the history of these trucks, it was my cheap wallet that caused me to by my '61 for a fun rod project--purists just shuddered and gave me stink eye.

Regarding fuel delivery, electric pump, even trial period will rule out delivery problem or not.
Regarding distributor, go Pertronics instead of HEI.
Regarding seat belts, I know an older post -2002- was about installation. Oft can be done in a day.