1970 E MFI will not start when hot

[Baxter2012]

I am hoping for suggestions
I go out in the morning after car has been sitting all night, it's cold turn it over several times and it starts up, takes longer than I would like but starts fine. Run around 20-30- miles runs great. Bring it home and shut it off wait maybe 20-30 min. Even a couple hours. If the block has any heat to speak of it will not start.
Wait till the next morning, starts up again.
I have checked to be sure I have spark and I do, people tell me I am losing fuel pressure, if so how would it build pressure when cold. No fuel leaks, fuel pump works fine, newly rebuilt as well as the MFI pump.
Any suggest would be much appreciated.
Thanks

[RSTarga]

Where are you located and what kind of gas are you running. We've discussed this issue before, the new fuels vaporize in the steel lines when left sitting hot.
The only work around I do, is to give the car part throttle when cranking hot. Don't pump, just give it about half throttle. If it the outside them is really hot 95+, you may have to go full throttle when cranking. As soon as it catches let off. You have to get fresh liquid fuel running through the tubing going from the MFI to the injectors.
Of course make sure your timing and dwell are spot on too.

[Baxter2012]

I live in GA but so far not hot
I never use ethanol fuel, I have a 72 s, and no issue. Can the lines actually get that hot in that location?? Any way to cool or deflect heat?

[RSTarga]

This is the time of year the refineries are switching to summer blends, you have some winter blend in your area still. The high humidity doesn't help either.
Are you sure there is not 10% ethanol in your fuel. Thats all we can get in Texas. Look at the pump it has to say wether it contains any ethanol.

[Richy]

You are not loosing fuel pressure to the MFI pump . There is really no pressure to loose , not like an EFI or CIS system . Have the injectors been tested ? They can leak. I recently checked a group of 13 injectors - 6 were good . Has the MFI been adjusted while driving with an AFR meter ? Maybe too lean , this can cause hard starting when hot . Follow RSTarga's starting advice . Sometimes not an easy problem to cure , no easy answer . How's the condition of the engine ?

[mar2mar]

I had the same exact problem on my 70S. It turned out to be the check valve at the fuel filter console. this valve regulates the low pressure side of the mfi.

[fgmec]

...Wait till the next morning, starts up again....

Already checked the MFI thermostat?
Could be dirty inside and it takes more time to return to full rich (start) position.

[304065]

Follow the steps in CHECK MEASURE ADJUST to the letter

Any competent Porsche driver tracks faster if brakes come smoothly

Air Filter
Compression Loss
Plugs
Dwell
Timing
Fuel Pressure
Injectors
Belt
Correlation
Smog

[Baxter2012]

I know I do not have ethanol
Has Msd box but not coil, order coil today
Will check fuel filter console had no idea the purpose there
Will then have injectors tested, I took them to auto shop to be checked but they need diesel pressure. If they were leaking down would I not have pressure starting cold.?

[Baxter2012]

Engine is brand new
Martin auto Europe 45 years experience, no mods