Just something that isn't quiet clear to me.

Had an issue with the relays on my relay board.
Cleaned them and took away all oxidation, problem solved.

But what is the use of the relay for the fuel pump? Even without this relay the engine fires up and runs smoothly?

Thanks

Can't. At least on my '74 2L.

You sure you pulled the correct relay? If so you may have some wiring issues. Does it cycle momentarily when you turn the key on, or does the pump run constantly?

Plus, i have seen some shady wiring regarding the fuel pump. More than once, someone ran a hot wire from the coil to power the fuel pump.

Sure I pulled out the correct relay. Nr 75 of the wiring diagram relay board: Haynes workshop manual

Because I am not a specialist, how could I check if the wiring is correct?
What do you mean by "cycle"?
Should the fuel pump not be running constantly?

Is your car still fuel injected? If so, the ECU provides an intermittent ground to prime the engine when the key is first turned to start. It then provides a constant ground to keep it running. If you have carbs, someone has bypassed the relay.

is the FI still on your car? the pump should 'cycle' for a few seconds when the key is in the first position to build fuel pressure.

If you have a 1.8L, then there is no fuel pump relay on the relay board.

more details on your car helps with the online diagnosis.

No.

When you turn on the key initially it should run for about a second then stop. then, when you go to the start key position it will run again, then after that power from the coil will engage the relay and keep the pump running.

If, on the other hand, you turn on the key and the pump continues to run without stopping, then someone hot-wired your fuel pump to the ignition power. While this "works", it's not good because you're no longer relayed, you don't know the source of the power (is the wire sufficient?) and if you get into an accident and the engine stops running the pump will continue to spew out fuel through whatever holes on your fuel delivery system you now have.

GA

Edit: ...and the responses above. This logic does not apply if yours is carb'd and/or not a 1.7 or 2.0

Hello,


Thanks already for the given information.

My car is an 1.7 by 1971 with fuel injection.

Indeed, when the motor, for some reason stops, but the ignition key is not completely switched off, the fuel pump keeps on running.

Should I consider changing it?

What are the possible dangers/damages when the fuel pump keeps on running?


Erwin

Danger of always-on pump is you have an accident or a fuel line comes off; engine stops and the fuel pump empties the fuel tank on the ground to start a really big fire.

Someone has re-wired your fuel pump to run all the time. They may have used a relay to power the pump but may have also wired the pump directly to the ignition switch.

Time to start chasing wires starting at the fuel pump. Find out where it gets its power.

Can you post a picture of the ffuel pump and the wiring? Sounds like it is wired directly to a switched power source and the fp relay is out of the circuit. Is the fuel pump in its original location, beneath the pass side engine shelve, or relocated?

I put one of these in my car. I got tired of the fuel pump running all the time. (Facet clicker mounted on the firewall.)

http://revolutionelectronics.com/Fuel_Pump.html




If it fails, I short the 2 purple wires together to run the pump.

Neither this nor the facet is stock and applies to the car above ...

I just went through this myself. PO had rewired the pump to bypass the relay because he apparently couldn't figure out that the relay was bad. Trace the wires back from the pump. You'll probably find a disconnected wire at/near the pump that runs to the relay and power to the pump coming from somewhere else.

OK, You got me.
I got side tracked by the fact that his pump runs all the time. Just presenting an alternative solution for safety's sake. Sorting the original wiring is the best solution in this case, of course. (BTW, that Facet is in the trash now.)