74Red80S

Hi everyone. I am new to the forums but have been a long time enthusiast. I recently got a 74 911S but with a 3.0 liter engine from a 1980 SC but am having an issue with starting the car which I hope someone may be able to point me in the right direction. The other day, I took it to a store 3 miles away, when leaving the store, the car died when I put it in reverse and wouldn't start again. Cranked and cranked for about 5-10 minutes, but wouldn't light up. I pushed it back into the parking spot and went back to the store, I came back after 10 minutes, car started right up and I was able to get it home. Thought maybe a gas vapor, though parked in a shady spot and car was sitting for at least 15 min. A few days later, I take it out again and it is running smooth, maybe 5 minutes into a drive going about 60 mph, the car just shuts off when I'm on a pretty busy road. Same thing, cranks and cranks, but won't start with trying for at least 5-10 minutes. Radio would still go on and emergency lights on so doubt it was electrical but not sure. After getting it off the road 15 minutes later, car fires up and I get it back home. I recently got new sparks, wires, distributor rotor as car was sitting for a while and was misfiring, but after that work, the car was running as best as it ever had. I hope a few more experienced readers can help with some suggestions, some thoughts I have had are fuel accumulator, timing, or vapor somewhere in the fuel lines. Anyone else deal with something similar?

TheTorch

Sounds like fuel line vapor lock. As the fuel lines cool, the vapor is returning to liquid and flows again, and you are able to restart. Might want to proactively change the fuel filter and accumulator. Others will have ideas where to look, but ideally where the fuel lines are closest to getting the most heat.

I have read some folks have had success using cans of air spray can dusters to blow on lines -- causing the fuel to cool and re-liquify. Might be worth having a can to try next time you get stuck.

Roy Gray

You need to determine whats missing next time you have this issue.Is it losing spark or fuel?A 74 iwth a 3l transplant,my money is on a bad connection somewhere do to human error--shoddy work.If this car is new to you you need to clean the crap out of all electical connections,the big ones.I.E.battery clamps,chassis grounds.Then replace fuel filter,and verify presence of fuel pump check valve/functionality.That little guy has caused errattic running or starting problems more than you can imagine.Note fuel appearance out of tank.How old is that tank?If its from 74 it should probably be thrown away.Does this car have the CDI from 80?Carbs or CSI?In my 35 years fixing all kinds of English,Italian and German junk(German junk being my fave)intermittent running issues always come down to something way more simple than you might be thinking.Dont throw any expensive parts at it,diagnose.These are simple cars,I have no doubt the solution will be also.