Engine shutoff while driving?, Yes, it had half a tank of gas. Options

[Ecterg42]

Hi fellas,

I had been driving my 75 2.0 FI on the highway for 4 hours on a hot day, with a couple of bio-breaks. After the last stop, while accelerating onto the highway, the engine shotdown. Stopped, checked usual suspects and after 10 minutes it started and I was on the road again. 15 minutes later I when through an interchange onto a different highway, and during acceleration it shut down again. Weather really hot now. This time it would not start again, cranked but was like it was out of gas. Fuel pressure was 30psi. Oil temp was 180 - 200 and the level was good. An oil cooler is mounted in frunk floor where A/C was.
Could the heat from the oil cooler have caused the fuel pump to vapor lock? What other sensors or devices could cause the engine to just shut off like that?

Car flat-bedded home,(AAA-yea). The next morning at home I gave it a try and it started right up and ran just fine.

Thanks,
Greg

I added a photo of the frunk showing position of oil cooler to fuel pump.

[GregAmy]

Join in there. Plenty of good suggestions.

http://www.914world.com/bbs2/index.php?showtopic=360458

[mepstein]

Sounds like vapor lock to me and I’ve BTDT in a couple 914’s. Where is your fuel pump? If it’s in back, I’d say it was the perfect storm for vapor lock. Once that area is heat soaked, it takes an hour to cool down.

Move your fuel pump to the front and problem solved.

[lesorubcheek]

Greg, it may well be vapor lock, but a symptomatically similar situation occurred about 40ish years ago to my 914. I was driving to school in the morning and after about 5 miles, engine died. Got out, looked around the engine compartment and didn't see anything unusual, tried again and it started back up. Just made it into the school driveway and it dies again. Turned out to be the ignition coil. My dad knew what to look at immediately after I described what had happened. Turns out some coils can fail when they get hot, but then work fine after cooling down. Just something else to consider.
Best of luck,
Dan

[Tjmrfe]

Hi fellas,

I had been driving my 75 2.0 FI on the highway for 4 hours on a hot day, with a couple of bio-breaks. After the last stop, while accelerating onto the highway, the engine shotdown. Stopped, checked usual suspects and after 10 minutes it started and I was on the road again. 15 minutes later I when through an interchange onto a different highway, and during acceleration it shut down again. Weather really hot now. This time it would not start again, cranked but was like it was out of gas. Fuel pressure was 30psi. Oil temp was 180 - 200 and the level was good. An oil cooler is mounted in frunk floor where A/C was.
Could the heat from the oil cooler have caused the fuel pump to vapor lock? What other sensors or devices could cause the engine to just shut off like that?

Car flat-bedded home,(AAA-yea). The next morning at home I gave it a try and it started right up and ran just fine.

Thanks,
Greg
I had a similar problem, now…I have a 75’ 1.8 so hopefully this is relevant…my connection at the dual relay was horrible. You didn’t say what your usual suspects were…The corrosion was the cause on mine. When I was on the road, I jiggled the connector and it started, I got home and changed all the connectors on the fuel pump side of the dual relay. That’s my experience. Good luck.
Terry.

[emerygt350]

I doubt vapor lock if its moving but it could be. I wonder about a cooked coil?

[GregAmy]

Vapor lock is almost a moot point on D-Jet. After all, the only place fuel is sitting and cooking is after the driver's side fuel rail...everywhere else it's circulating back to the tank to be re-cooled and eventually re-heated...

The issue with 914 D-Jet today is almost always electrical. Relays, relay boards, wiring harnesses, fuel pumps, sensors, etc.

Mine was bad fuel pump relay pins and/or bad pins at the relay plate terminals.

Or maybe some kinda electrical ju-ju, I dunno.

[mepstein]

I doubt vapor lock if its moving but it could be. I wonder about a cooked coil?

Mine used to stall out at 60mph. Vapor lock.
I was at an event in Georgia in Bob Hill’s/Saigon ‘73-2.0. He had it on the drive down and then multiple times on the group ride. First we stalled into a parking place for lunch. Then after lunch it started again about an hour in. We had to get a spray bottle of water and spray down the fuel pump. It would last for 15 minutes and then repeat 4x to get home. He moved the fuel pump to the front and that fixed it. Porsche had a service bulletin on moving the pump.

I’m not saying that’s the only thing it could be but it sure fits.

[GregAmy]

Mark, didn't the '75 already have the fuel pump up front? Not clear on the DNA on that.