Question: would a stock FI fuel pump fuel through another fuel pump mounted in-line, but not running ?
My thought is to install a second FI pump, either in-line or in another location with a switch.

Why?

I've had a fuel pump overheat and quit working. Spent an hour or so by the side of the road waiting for it to cool down and self heal. I've thought about how nice it would have been to have been able to restore fuel pressure at the flip of a switch. I'm not sure running a second unit in series would work. There's a check valve to be considered. Perhaps running one in parallel would work better. You'd need to bench test the idea first.

You would still need a valve. In fact, you'd need one for each pump.

Why not simply carry a spare pump?

Stop thinking so much Jim.

Mounting the pump in an easy to reach location and carrying a spare seems like the best idea. "Easy to reach" can be debatable.

That's exactly what I do now, although it's a bit messy to swap it out.

My question is whether one running pump will push fuel through a second pump that is not on at the same time ....

Parallel with check valves.

Maybe but it will add load to the first pump. Like Andy said why not just carry a spare?

If you move it to the front, it won't overheat. It will also make it easy to change if you duplicate the '75-76 fuel hatch on the firewall. Then you could do a replacement with just a screwdriver and not have to get underneath the car. Bob Hill / Saigon71 just did this mod due to the vapor lock he had at octeenerfest. 4X in one day. I was in the car.

Relocating the pump to the front is one of the easiest mods and eliminates the vapor locking issues. While you're at it, add a starter solenoid (as written up in another thread on this forum) and you'r making the car even more bulletproof.

And in response to the original post, adding another pump in series rather in parallel would probably work best, but would require many more fuel line connections. I think carrying a spare and moving it up front with the firewall mounted fuel pump plate would be the best and easiest solution.

George, I think you mixed up series and parallel. Parallel would be better but requires more connections.

I agree that moving the pump, or keeping hot air away from it (or ducting cool air onto it) would be a better solution, though.

Come to think of it, if the pump just plain stops working at all, it is probably on the way out and should be replaced anyway.

--DD

Well, with that mindset we will need to carry a spare of every part on the car that would leave us on the side of the road. I could make a long list of those parts. They would probably fill up both the trunks. Sorry Jim, imho, ridiculous idea.

This is the only way it can be done.

Thanks for all the input. The car is a '75 and fuel pump is in the stock location. Plan B is to put a second blister pack on the passenger side

But what if the first pump in line died. I don't think the second pump wouldn't suck it from the first. Hence parallel. Plus you could add an A/B switch - more electrical goodies for Jim!

Parellel it is...

Parallel with check valves is the way to go. They start at $10 and go up from there.

We've established that it should be parallel. I still haven't figured out why all of this? I've never had a fuel pump failure, so I wouldn't put this much effort into a redundant system on a part that rarely fails. We can't just build redundant failover backup systems all throughout our cars. Making adjustments to the critical systems and interfaces that would make them easier to swap out in case of failure, that I'd get.

If that is the case, the pump is dying or the electrical connections are intermittent. Fix the problem rather than band-aiding it with the extra complexity of dual fuel pumps.

--DD

Keep is simple Jim. Two fuel pumps doubles your chances of a fuel pump failure. If you're looking for a project, why don't you buy another car to work on. Make it as nice as the one you have now. That should fill your days for awhile.

Duh.... don't you know 914's fly!
It's an FAA requirement.