Vapor lock or something else?

[hoodup]

1. 68 GMC with a 350 cid. when its cold it fires right up every time.
2. After its warmed up its not as easy to start.
3. when i open my fuel cap i get a a rush of air and fuel...most times

There was an earlier thread along these same lines and someone made mention of fuel cap issues and fuel line being to close to a heat source.

Ive since changed to a vented cap to see if that keeps me from being kissed with fuel at the pump.

Any ideas why I'm having vapor lock issues? Please help!

Thank you in advance

[Wootdog]

This may seem slightly off topic but do you have headers? If you do, they overheat the starter solenoid which makes it hard to start while the engine is warm. The help section at most auto parts places has a cover for the solenoid.
Does the truck have an inline fuel pump in the tank? Or is it in the cab? I had a 90 Z28 with the fuel pump in the tank. When it started going bad, I had the exact same symptoms you have. Replaced the fuel pump in the tank and ran great.
Kerry

[hoodup]

In fact I do have long headers and they do run close to the starter! as for the fuel pump the only one I know of is on the block, But that's my ignorance in not knowing if in fact there is one in the tank. I know for sure its not on the cab though.

[BLK96]

Mount a Ford starter solenoid in place of the junction on passenger fenderwell, rewire accordingly where starter and solenoid get full 12v from large batt cable and heat-soak will be a thing of the past.

[hoodup]

Just a thought but can my ignition mod be failing?? the truck starts great when cold but not always well when its warm.

[Shyguy]

Usually if the module is going bad the truck will die after it warms up. At least I have found it to be the case.

A module is not that expensive and easy to replace. I changed mine out and carry the old one as a spare in the glove compartment after I had it tested good at O'Rielly's.

Does your engine turn over ok when it is hot and not start, if so it is not a starter/solenoid problem.

Danny

[hoodup]

yes it does turn over great! i just does not ignite/fire. Is the fuel atomizing?

[woodwright]

Did this get sorted out? Mine is doing the same thing.

[cdowns]

if you have an air rush when removeing the gascap you have a venting issue with your gas tank nothing to do with any electrical components having headers are anything else that the parts changers would have you believe

[DT1]

Originally Posted by cdowns

if you have an air rush when removeing the gascap you have a venting issue with your gas tank nothing to do with any electrical components having headers are anything else that the parts changers would have you believe

I agree. Try removing the gas cap before you attempt a hot start.

[hoodup]

well it is sorta sorted out but i live in Montana so it hasn't been warm enough here for it to get really hot, that's when it really does it. But i do have gas tank venting issues but im not sure what to do about it. i even have a vented cap