454 just dies.

[C30Seenemall]

I am Baffled, Puzzled and Flabbergasted, otherwise known as Wayne.
My mechanic and I have been trying to figure out why the 454 in my C30 Scottsdale Camper Special keeps dying.
The problem?
Each time I drive the truck a total of 26-29 miles, the engine sputters then dies. I can pull off the road (not easily with no power steering) put it in park and it fires up easily. If I continue to drive it will go about 1 or 2 miles then quit again.
The mechanic and I think it is vapor locking but we aren't sure why. The previous owner put an electric fuel pump that seems to work fine but they installed rubber fuel lines. The mech found the lines were about 1 inch from the exhaust pipe! He subsequently moved it about 4-5 inches from said hot pipe.

But the engine is still dying on me.
My opinion is the fuel lines should always be steel instead of rubber under the truck. Am I correct in thinking that?

[geezer#99]

When it quits, look in the carb and stroke the throttle.
If it's vapor locking you likely won't see any fuel from the accelerator pump nozzles.
Also pop the gas cap off when it quits.
If it makes any noise it might be you need a vented cap.
And metal lines are better.
Why the electric pump?
Can you install a mechanical one on the motor?

[68post]

I'd also check; the coil, the rotor (for burn thru or blackened arcing spots and rust deposits on the underside), and the module.

[C30Seenemall]

Originally Posted by 68post

I'd also check; the coil, the rotor (for burn thru or blackened arcing spots and rust deposits on the underside), and the module.

Thanks! When I had one of my many 55 Chevys, it did the same thing (sort of) by dying, then waiting and it would fire back up. I learned the coil was bad and once replaced never did it again. The build up then discharging routine had worn the coil out (from what little I understood of the process).

I also was told the early GM HEI's were notorious for their failure rate.
Is that true?
Thanks again!
Wayne

[ElKotze]

Yes, a coil can do that, but the fact that it always dies after you drive a certain amount of miles leads me to a gas cap that is not venting correctly. The pump is drawing a vacuum that eventually is getting too big for the pump to work against. Also check the return line if you have one, maybe it didn't get hooked up right when they put in the elec. pump.

[68post]

I had a '90 S10 years ago that would die when the divorced coil got hot. A $30 coil fixed it.

[C30Seenemall]

Originally Posted by ElKotze

Yes, a coil can do that, but the fact that it always dies after you drive a certain amount of miles leads me to a gas cap that is not venting correctly. The pump is drawing a vacuum that eventually is getting too big for the pump to work against. Also check the return line if you have one, maybe it didn't get hooked up right when they put in the elec. pump.

Thanks! That sounds like the first place to start.
Another Member suggested looking at the gas cap too. Do we have a consensus here? LOL!

[franken]

Try driving w/o the gas cap.

[Justins76]

Might be that electric pump.

When it dies, can you put it in N and crank it while coasting? If it will start up, might help you avoiding having to pull off the road.

[C30Seenemall]

Originally Posted by franken

Try driving w/o the gas cap.

Good suggestion! I'll try that. Thanks!

[C30Seenemall]

Originally Posted by C30Seenemall

Good suggestion! I'll try that. Thanks!

Which brings me to the question; were the fuel tanks on my C30 vented from the factory? Either on the cap, or the gas tanks themselves?
Where would the vent be on the gas tank? If the cap were vented, where would the hole be located to efficiently vent?

On the 65 Chevelle I am rebuilding, there is a vent tube at the top of the tank on the passenger side.
I can't find a schematic that shows how or where the tanks may be vented.

[Boog]

I'll assume you are running the stock quadrajet carb. My experience with those symptoms were the result of the filter in the carb plugging up with gunk from the tank. It ran just like yours.
It was a 454 in a 72 chevy wrecker. We kept spare filters in the glove box.
Also note there are 2 different lengths of those filters too.

[Jimal]

Originally Posted by C30Seenemall

I am Baffled, Puzzled and Flabbergasted, otherwise known as Wayne.
My mechanic and I have been trying to figure out why the 454 in my C30 Scottsdale Camper Special keeps dying.
The problem?
Each time I drive the truck a total of 26-29 miles, the engine sputters then dies. I can pull off the road (not easily with no power steering) put it in park and it fires up easily. If I continue to drive it will go about 1 or 2 miles then quit again.
The mechanic and I think it is vapor locking but we aren't sure why. The previous owner put an electric fuel pump that seems to work fine but they installed rubber fuel lines. The mech found the lines were about 1 inch from the exhaust pipe! He subsequently moved it about 4-5 inches from said hot pipe.

But the engine is still dying on me.
My opinion is the fuel lines should always be steel instead of rubber under the truck. Am I correct in thinking that?

What carburetor are you running?

[C30Seenemall]

Originally Posted by Jimal

What carburetor are you running?

It is the stock carb-a QJet.

[b454rat]

Not sure it helps or not, but I was having issues when I lived out there. I had a 97 Chevy 2500HD with a 454. Had 57k when I bought it, ran and drove perfect. After I got out there, whenever I would get gas, there was a lot of pressure when removing the gas cap. I had to crack it open slowly not to get sprayed with gas. I can't remember if it helped or not, leaving the cap opened a little bit. I left there and came back east, and never did it again. Not sure what the altitude did, but thought was weird. I did notice a power loss, but I understand why.

[bigmac73]

has anybody pulled out the fuel pick up tube in the tank and see if the original sock style screen is still in-place I have had those rust up and plug up in the past I always just remove them

[87Skier]

Check the distributor cap as well. It is unlikely but I had one die on my boat and it had similar symptoms. Would run for some time then suddenly quit. Would fire back up and continue the process. The way I finally figured that one out was to get really mad and go WOT until it quit.

I've also heard of some distributors with worn shafts that will run intermittently. I don't think that is your issue though.

[C30Seenemall]

Originally Posted by C30Seenemall

I am Baffled, Puzzled and Flabbergasted, otherwise known as Wayne.
My mechanic and I have been trying to figure out why the 454 in my C30 Scottsdale Camper Special keeps dying.
The problem?
Each time I drive the truck a total of 26-29 miles, the engine sputters then dies. I can pull off the road (not easily with no power steering) put it in park and it fires up easily. If I continue to drive it will go about 1 or 2 miles then quit again.
The mechanic and I think it is vapor locking but we aren't sure why. The previous owner put an electric fuel pump that seems to work fine but they installed rubber fuel lines. The mech found the lines were about 1 inch from the exhaust pipe! He subsequently moved it about 4-5 inches from said hot pipe.

But the engine is still dying on me.
My opinion is the fuel lines should always be steel instead of rubber under the truck. Am I correct in thinking that?

Finally figured out the engine dying problem. Replaced the electric fuel pump and it pumps better than the old. Had a "heat shield" installed around pump to help keep it as cool as possible. Tanks are well vented and spark was good (not great) plus made sure gas was getting to the inlet side of carb. SO I did last what I should have checked first () I found the brass filter inside the carb inlet had bits of white tape all over it (plus sediment). Seems someone had put pipe tape/compound around the inlet nut threads. Did I feel stupid then! Anyway, replaced that with paper filter and it runs forever now! Thanks for all the suggestions, tips and info!