Symtoms and cures for vapor lock
 

I have noticed lately that when my truck gets hot from highway driving or even in town driving, the truck will have a low idle and sound like its going to die. It also sometimes wont start if it has been sitting and I have to use starter fluid. When this happens, gas is still squirting from the accelerator pump though. Tonight on the freeway, when ever I came to a stop, I had to keep my foot on the gas and brake to keep the truck alive. I also noticed that the clear fuel filter was empty and only little burps of fuel was going through it (I couldnt believe the truck was still running). The fuel pump is new. Could this be vapor lock? What are ways to cure this?

Re: Symtoms and cures for vapor lock
 

If it is indeed vapor lock, a phenolic carb spacer can help some with that.

Re: Symtoms and cures for vapor lock
 

Ha, crm318, just noticed your avatar...the donor car for my engine was a "Melba Toast," 70 Chevelle SS. I think the one in the movie might have been an LS5, but I still get a kick outta having that connection.

Re: Symtoms and cures for vapor lock
 

do you get a pressure buildup in your gastank? wwhen this happens try taking the gascap off , if you hear a whooshing sound that means you have a venting problem from not having the tank vented

many times with old vehicles there can be alot of crap in the tank. it is not unusual for the sock strainer on the pickup tube in the gastank to be clogged with gunk and crap

Re: Symtoms and cures for vapor lock
 

allright allright allright! I LOVE that movie! :)


And yes, Wooderson's Chevelle was an LS5.

Re: Symtoms and cures for vapor lock
 

Aloha
"Man I love them red heads!" :bo2:
Mine did the same thing I replaced and re routed the fuel line away from the headers and mounted the fuel pump on the out side of the frame rail, still was getting air in the fuel filter, put on new lines from the tank but still had the problem, so I changed the fuel pump and the problem went away, now I know you said you even put on a new pump , so I would check the fuel lines from the tank making sure they are all tight.
My buck 2.98's worth!
Aloha
Marty
PS btw our fuels now have alcohol in em and it evaporates faster than gas, I have heard here in Hawaii they want to add more alcohol to the gas! costs to much to import oil here I guess,

Re: Symtoms and cures for vapor lock
 

I just had the had the tank out the other day to empty and clean it. The sender was clean and I removed the sock a while back. I will check the cap the next time it happens.

Re: Symtoms and cures for vapor lock
 

Had the same problem on a 68 once. Got a locking gas cap and it solved it. The locking cap seems to let the vapors escape better...just a thought:chevy:

Re: Symtoms and cures for vapor lock
 

What carb do you have? I have been dealing with this problem for a while now.
New tank, new lines, new fuel pump, new fuel filter and still there. The only thing I can figure is that my rochester carb float is sticking a occassionally or the choke. Its an intermittant problem. The only thing I can think it is my carb. Gonna replace it when I have the cash for an Edlebrock I think.

Re: Symtoms and cures for vapor lock
 

i pressurerd my tank with air and found my fuel line had a cracks in it and was sucking together and causing vapor loc replaced line and problem solved.

Re: Symtoms and cures for vapor lock
 

I have a quadrajet. Ill inspect the fuel lines.

Re: Symtoms and cures for vapor lock
 

Might sound crazy, but you can put a few wooden clothespins on the metal fuel line by the carb to act as a heat sink. Of course for a long time fix it would look pretty silly but if it cures your problem at least you know for sure it was vapor lock!

Re: Symtoms and cures for vapor lock
 

I agree, A bad gas cap can definately cause vapor lock. Back in the 80's, I had a 77 Ford with the tank behind the seat and it would vapor lock on the freeway all the time. Used to reach out the window and pull out on the cap to release the pressure. Too lazy to buy a new cap back then.

I have a locking gas cap on my 69 :chevy:

Re: Symtoms and cures for vapor lock
 

Yep same carb as me. Im betting its the carb, at least for my issues. When mine bogs down and tries to die it I have a lot of smoke coming out only the drivers side exhaust pipe.

Re: Symtoms and cures for vapor lock
 

So CRM318 did you fix your problem yet?

Re: Symtoms and cures for vapor lock
 

Not yet Kevmic28. The other night I was stranded in a parking lot for 20 min while my truck cooled off. I notice that if I used starting fluid (which I didnt have on me), it will usually crank up.

Re: Symtoms and cures for vapor lock
 

My dad has a 86 c10 with the 305 in it and it always vapor locked on us after shutting it off. I ended up cutting the metal line from the pump to the carb and replaced it with a rubber fuel line and moved it away from the engine as much as possible. Solved the problem. The factory fuel line was in-between the bock and water pump. It got so hot I couldn't even touch it with out getting burned. now I just have to fix the evaporation from the fuel bowls so we don't have to spend 15 mins to get gas to the carb every time. Thinking about putting in a 1 way valve.I'm only 18 btw.

:gmc2::chevy:

1976 gmc k15-86 chevy c10-1994 chevy s10-03 chevy duramax 2500-05 Buick lacross