Fuel Pump Check Valve Application question

I replaced the fuel accumulator on my 1977 Porsche 911S, but am still having vapor lock hot start problems takes 8-10 hours on a hot day before the cars starts again. I was going to replace the check valve next, but cannot find the appropriate part here at Pelican. Product 893-906-093-M14 starts at 1978 and goes up, but mine is a '77. Help! : Thank you.

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[Casey at Pelican Parts]

Is your car CIS? I show that to be the correct number is it is a CIS equipped vehicle.

- Casey

[gerber28]

Have you checked your residual fuel pressure. I had a similar problem with my 79 SC and ordered a new check valve (12mm) that did not fit. If the banjo fitting on the outflow side of your fuel pump is 10 mm the pump has an integrated check valve and has to be replaced to restore the check valve function.
I'm not sure if my 79 had fuel lines through the tunnel replaced with an earlier version (which I doubt) or Pelican's listing is incorrect and the external check valves and larger fittings are 1980 +. Maybe others with more experience can help us out here.

[boyt911sc]

Originally Posted by Havolas (guest)

I replaced the fuel accumulator on my 1977 Porsche 911S, but am still having vapor lock hot start problems takes 8-10 hours on a hot day before the cars starts again. I was going to replace the check valve next, but cannot find the appropriate part here at Pelican. Product 893-906-093-M14 starts at 1978 and goes up, but mine is a '77. Help! : Thank you.

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This post was auto-generated based upon a question asked on our tech article page here:

Havolas,

Vapor lock does not happen in CIS. You might be referring to carbureted system where the system operates at very low fuel pressure. Even if you intentionally filled the fuel lines with gas or vapor, they would be expelled when the fuel pump delivers fuel to the system. From reading your initial post, I suspect ignition problem when the engine is hot. Check for presence of ignition sparks next time you encountered a no-start problem. What brand is the CDI? Is it a Bosch? Or a Permatune?

BTW, you need a fuel pressure gauge to do a meaningful diagnostic tests for fuel injection system. Otherwise, you leave too many unknown variables and makes the troubleshooting more difficult.

Tony