Atmos fuel pump

I have just finished rebuilding the carbs replacing the water pump and replacing some of the coolant hoses. Struggling to get it to fire up. I can’t hear the fuel pump running with the ignition on. I understand the pump goes through the tachometer relay. The wiring diagrams are not a lot of use in understanding the interaction. Does anyone know the way this relay works in operating the fuel pump.

Dave

I can’t hear the fuel pump running with the ignition on.

That's right ............... The fuel pump will not operate unless the engine is either running, or it is being cranked. The fuel pump relay gets pulses from the switched terminal on the ignition coil.

Cheers, that’s what I thought. I think it’s goingto take a bit to prime the system after a total clean of the system

[mettersl]

Hi Buzzer,
I had problems with this relay initially when I recommissioned the car and fitted a bypass switch to allow priming, tjhe few seconds before and after ignition pulses was not enough.
The other thing to check is that the connection back to the relay are tight, IIRC there are a few, you should hear both the relay and the pump when you turn on ignition and after turning over.
Lee

Lee, thanks. But I found something interesting in that the fuel lines under the car have some damage both the feed and return have been damaged. also an other pipe running under the chassis are also damaged. The car is plumbed for aircon and these are also damaged. I've attached some pics. rather strange as it was running before I started working on it and I can't recall seeing the damage on my original inspection. there may also be enough bypass to run on tick over and keep the fuel bowls full.
So my next plan is to replace the damaged parts of the pipes and rejoin.

[mettersl]

One more problem that I had that you might find Intersting and relevant...the reason I had a fuel pump relay override was occasional fuel starvation- it would not go up steep hills without bucking.
This turned out to be a blocked return pipe, when that happens the pump stalls (its a centrifugal design) and the fuel pressure regulator cannot function...this causes low fuel pressure.
Once I cleared the pipe, fuel pressure went up and a couple of the unions started leaking...but that was easily fixed. From that point on, no starvation.
Looking at your pictures one of the pipes is very crushed, if that's the return, it will have the same impact.
Cheers...

Actually the feed and return are both crushed in different places. It as if the car was lowered onto something underneath in the middle of the car as the damage is very contained just on the pipes. No other sign of damage I can find.

I had to cut out a metre of the feed fuel pipe and replace it. it had 3 areas of damage and the return i just had too cut out one piece of damage. result the motor fired straight away. The restrictions were enough to stop it priming but I guess allowed enough previously to run the engine.
Next challenge is ignition timing check then set up the carbs

Dave