1972 1.7, D-jetronic fuel injection, possible bad fuel pump?

[allwhitekeys]

Hello, My car has started to stop running after driving it just over an hour. It will start up and run ok after waiting for 30 minutes. The first thing I did was put a ground connection on the engine cylinder sensor that feeds the control unit and take another test drive, it died again. Next I verified that I had spark on one of the plugs after the engine died. Also checked the fuel pump was working by turning the ignition key on and off and the fuel pump work for a second or two each time. And last I checked the fuse connection and tested each relay on the relay board. I think I may have a bad fuel pump but they cost over $400 so I want to be sure, can anyone help me?

Danny

[Zuffenwerker]

Sound like you need to hook up a fuel pressure gauge and jump the F/P relay. Usually when pumps die they really die so may not be a bad pump.

[Dave at Pelican Parts]

Throwing parts at a problem is a really good way to empty your pockets and not solve your problem.

You need to figure out what is causing the car not to run. It may be a fuel delivery problem--the easiest way to tell is to have a fuel pressure gauge installed so you can check it when the car has died. I actually have a small one in the engine bay that is more or less permanently plumbed in.

It's good that you checked for spark; that is a relatively easy thing to lose when stuff wears.

It would be very strange indeed if there were any problems with air going in (or compression) that only started after an hour of driving. Stranger still for it to resolve itself after 30 minutes.

It is possible that you have trash in the fuel tank that eventually gets sucked into the intake, blocking it completely or partially. Eventually when the pump is no longer running it will float away from the pickup. It's worth using a light (NOT A FLAME, PLEASE!) to take a look into the tank to see if you can see anything like that.

--DD

[allwhitekeys]

Thanks Dave, you are so right, throwing parts at a problem is just not good. I will take a look in the fuel tank soon. I have been trying to get a fuel pressure test kit but so far I can not find a kit that comes with the 7mm adapter that I need to connect it to the fuel rail on the car. Do you know where I can find one?

Thanks

[Dave at Pelican Parts]

Your local plumbing supply store? I used brass plumbing supplies to hook my gauge up.

--DD

[allwhitekeys]

OK I will check a plumbing supply house. I took a look into the fuel tank several times and it looks clean but its hard to see everything. I want to get that fuel gauge installed and test the car again.

Thanks