Truck is slowly breaking down on cross-country trip, help!

[Xavier]

Hey guys, my '68 C20 with a 327 and manual 4-speed is giving me multiple problems. I was planning on towing the truck across country but last minute plan changes forced me into driving it without having time to properly prep it.

Symptoms started with a misfire, likely due to the plug wires cooking on the headers. I attempted to buy replacement wires en route but I neglected to get a set for an HEI setup (Delco Remy) and just ordered them by year/make/model so I obviously ended up with wires intended for points. I was able to get the correct wires the next day but that didn't change the miss at all. I had a brain fart and forgot to change the plugs at the same time.

After about 1,200 miles I started experiencing what seems like a fuel starvation issue. I would be going down the highway and the truck would start to sputter and buck until I let up on the throttle. I could then lightly press the throttle to maintain speed but anything more or hitting an incline would bring back the sputter. I limped like this for over 100 miles before stopping for fuel. After the re-fuel it ran like a champ... for about 20 miles. Then the starvation symptoms returned. I couldn't source a fuel sender locally but I did replace the in-line fuel filter and the mechanical pump. I opened all the lines from carb to tank and blew them out, there wasn't really much in them. I know the sender doesn't have a sock on it and my tank is rusty but I was able to drive another 700 miles today before the starvation symptom popped back up.

Looking for some advice on what to look at because I still have another half of the country to cross.

[truckster]

From your description, I think your best bet is to have some spare fuel filters with you. It sounds like your tank is full of crud, and you probably don't have time to remove it and clean or replace it.

[Xavier]

@truckster, noted. I should have grabbed a few more once I saw what poured out of the original.

@camtoys, I didn't know you could get socks on their own, I'll have to check that out.

@Stocker, it is indeed a quadrajet and I did take a peek at the filter when I opened all of the lines and it looked ok but I suppose it wouldn't hurt to replace it. Trouble is I was at a buddies shop when I opened everything up and I don't have a 1" wrench on me for that fitting.

@berudd, I actually was going to try that today but I couldn't find a universal electric pump with a low enough pressure to keep the quadrajet happy.

@LockDoc, currently just north of Austin, TX. Heading to PA.

[Stocker]

Originally Posted by Xavier

@Stocker, it is indeed a quadrajet and I did take a peek at the filter when I opened all of the lines and it looked ok but I suppose it wouldn't hurt to replace it. Trouble is I was at a buddies shop when I opened everything up and I don't have a 1" wrench on me for that fitting.

Last year my filter plugged which is what made me think of it now. The truck ran fine on level ground but starved out & died from lack of gas when going uphill. The carb had been rebuilt a few years before so I incorrectly assumed the filter had been replaced. When I removed the paper filter it looked good but it was plugged so badly that I couldn't blow air through it at all. I put in a new sintered bronze filter and that fixed it.

If you suspect that could be your problem, you might be able to borrow a wrench from a parts store. Or buy a cheap one, or a cheap adjustable (Crescent) wrench. Good luck and let us know what you find.

[RTHarvey]

Originally Posted by Stocker

Last year my filter plugged which is what made me think of it now. The truck ran fine on level ground but starved out & died from lack of gas when going uphill. The carb had been rebuilt a few years before so I incorrectly assumed the filter had been replaced. When I removed the paper filter it looked good but it was plugged so badly that I couldn't blow air through it at all. I put in a new sintered bronze filter and that fixed it.

If you suspect that could be your problem, you might be able to borrow a wrench from a parts store. Or buy a cheap one, or a cheap adjustable (Crescent) wrench. Good luck and let us know what you find.

I had a similar experience. The paper filter at the carb looked fine, but couldn't blow thru it. replaced it, and all was well. I am with the guys that suggest that since replacing the filter helped, you should try that again, and the carb filter too.

[camtoys1]

you also could probably pick up a shock for the sender at a parts store and like trucker said have some spare fuel filters and if your good at carb work pull the top and clean the bowls out and clean with brake cleaner

[Stocker]

If it has a Q-jet (or other Rochester, I think), there's a small filter where the fuel line enters the carb. If you didn't replace it already, it could be plugged which will cause starvation like you describe. The small filters are either pleated paper or porous bronze. The bronze one is best. It can be installed in either direction but it's supposed to have the cone facing the fuel line.

[berudd]

You go full on Roadkill and get a plastic tank, put it in the bed and run a fuel line to it. Extra points for using extra zip ties.

[LockDoc]

-
Where are you at this time?

LockDoc

[camtoys1]

here is the part number Airtex FS253 Universal Fuel Sending Unit Strainer with 3/8" Pickup Tubes, 2 3/4" Long

Airtex FS254 Universal Fuel Sending Unit Strainer with 5/16" Pickup Tubes, 2 3/4" Long

[special-K]

I'd definitely be changing that in-carb filter, and carry a couple extra. The sock is a good idea, but on the road maybe it would be best to filter (disposable) the tank crud between the tank and fuel pump, unless you get to a good place to do the sock. Hopefully a new sock will stay clear for the rest of the trip

[HO455]

Just throwing ideas out. Try removing the fuel cap maybe the vent is partially plugged. Your fuel pump could be sucking air. Check the hoses and the fuel line for damage.

[57taskforce]

A couple years ago when I first started driving my K20 around after it had been sitting for a few years, For the first month or so it ran pretty good. Seemingly overnight it started running rough/ missing at idle. On the way home from the store I had to crawl home on the side of the road in four low. The carb (edelbrock) had some trash in it. 1 carb kit later and it was good again. It really doesn’t take much to slow the fuel flow down enough to cause problems. I would load up on the external filters and the carb filters both.

[nikwho]

I run NAPA part #3033 fuel filters they're dirt cheap (like $3 or $4, IIRC) and keep changing them until you get all of the crud out of your tank!

[Stocker]

^^ That looks just like the filter I have under the truck, between the tank selector and the fuel pump.

[toolboxchev]

If you have an HEI the module in the distributor will give you exactly the same symptoms.

How do I know??? Been there. Also the Coil will do the exact same thing.

[68C15]

Originally Posted by toolboxchev

If you have an HEI the module in the distributor will give you exactly the same symptoms.

How do I know??? Been there. Also the Coil will do the exact same thing.

Or a missing ground strap under the coil

[vics stuff]

As a suggestion have you looked into your fuel pump. You could be experiencing inadequate fuel pressure and volume after the truck warms up.
Good luck
Vic

[Hoosier Rick]

My dad bought a 1977 C20 camper special out of an estate in about 1987 that only had about 20k on the clock. The right fuel tank had rust in it. I put a see through inline fuel filter in line to that tank, then another near the fuel pump. He threw a couple of spares in the truck. A couple of tanks of fuel through it (and changed a few filters) and the problem was gone. A lot easier to change an inline filter along the road(and safer) than to change one in the carb on a hot engine.

[LockDoc]

Originally Posted by Hoosier Rick

My dad bought a 1977 C20 camper special out of an estate in about 1987 that only had about 20k on the clock. The right fuel tank had rust in it. I put a see through inline fuel filter in line to that tank, then another near the fuel pump. He threw a couple of spares in the truck. A couple of tanks of fuel through it (and changed a few filters) and the problem was gone. A lot easier to change an inline filter along the road(and safer) than to change one in the carb on a hot engine.

If you have a lot of sediment in the system you will still have to change the in carb filter. Believe it or not, it will catch the finer stuff that the larger in line filter will not, and plug up. I found that out on my '70 Chevy truck.

LockDoc