A vapor lock issue?, Starting after 30 minutes or so of sitting Options

[boxsterfan]

So on my 74 2.0L D-Jet, my car normally behaves this way on cold start:

1. Starts right up and idles high while cold
2. As it gets warmed up, the idle "hunts" between 0 RPM and 1200 RPM and can occasionally die when pulling up to a stop sign (you might have to blip the throttle).
3. After she warms up, she idles perfect at 900-950 RPM.

The problem:

1. Car is warmed up driving to a store (idling perfect 900-950 RPM)
2. Go into store for 30 minutes
3. Start car (starts for a second but then dies if you didn't give it any gas)
4. Turn key off
5. Turn key right back on and it doesn't want to start (just cranks). But if you give it gas while cranking you can get her to start....almost like push starting the motor and popping clutch).

Note: My fuel pump is in the front. Stainless steel lines in the tunnel.

Am I still experience vapor lock?
Failing CHTS (also related to idle hunting)
Other?

[Cap'n Krusty]

Listen up! I'm old enough to have worked at a dealership when these cars were new. I did pre-delivery inspections, services, warranty work, and even major engine repairs on these cars. Lotsa test drives. 2 liter 914s ALL did this from the get-go. Every one of 'em. Floor the pedal, let it off as seems prudent. The FI guys at the Porsche training center were well aware of it, and attributed it to what they called "an electronic lie". The rather dumb analog control unit was unable to prioritize signals, and couldn't allow for heat soak, ambient air temps, and many other factors that are a piece 'o cake for next-gen and later systems. That's also why we sometimes had to unplug the TS1 in the plenum in order to make them run right.

The Cap'n

[boxsterfan]

Listen up! I'm old enough to have worked at a dealership when these cars were new. I did pre-delivery inspections, services, warranty work, and even major engine repairs on these cars. Lotsa test drives. 2 liter 914s ALL did this from the get-go. Every one of 'em. Floor the pedal, let it off as seems prudent. The FI guys at the Porsche training center were well aware of it, and attributed it to what they called "an electronic lie". The rather dumb analog control unit was unable to prioritize signals, and couldn't allow for heat soak, ambient air temps, and many other factors that are a piece 'o cake for next-gen and later systems. That's also why we sometimes had to unplug the TS1 in the plenum in order to make them run right.

The Cap'n

Thank you for the insight o'Krusted one. (IMG:style_emoticons/default/beer3.gif)

I guess one day I'll get this fixed by switching to MegaSquirt or my ninja LH-Jet project. (IMG:style_emoticons/default/ph34r.gif)

[ky914porsche]

Listen up! I'm old enough to have worked at a dealership when these cars were new. I did pre-delivery inspections, services, warranty work, and even major engine repairs on these cars. Lotsa test drives. 2 liter 914s ALL did this from the get-go. Every one of 'em. Floor the pedal, let it off as seems prudent. The FI guys at the Porsche training center were well aware of it, and attributed it to what they called "an electronic lie". The rather dumb analog control unit was unable to prioritize signals, and couldn't allow for heat soak, ambient air temps, and many other factors that are a piece 'o cake for next-gen and later systems. That's also why we sometimes had to unplug the TS1 in the plenum in order to make them run right.

The Cap'n

Thank you for the insight o'Krusted one. (IMG:style_emoticons/default/beer3.gif)

I guess one day I'll get this fixed by switching to MegaSquirt or my ninja LH-Jet project. (IMG:style_emoticons/default/ph34r.gif)

My "new" 1975 914 2.0 has shown this same inconvenient little nuance during hot starts. It is solved by holding down the gas peddle big time during hot startup, but now my gas pedal push rod keeps disconnecting between the gas pedal and the throttle. It has a new push rod with ball to go into pedal and ball to go into throttle, but those 2 little balls are way too finnicky when the gas pedal is aggressively feathered up and down. I've got to find a way to make them stay in place better, because I'm tired of pulling off the side of the road to reconnect the gas pedal rod to the throttle in the floor.

[TheCabinetmaker]

Ky914, replace the gas pedal. It's the socket that gets worn