Can anyone help with a Fuel pump Relay issue?

My fuel pump wasn't wired correctly, straight to the ignition it worked fine but obviously not a safe way to do it.
I bought what I thought was the correct one off eBay,
Engines fires and runs fine but the relay is clicking open and shut wildly, it clicks louder and faster as the revs increase, I'm sure it'll be burned out in no time.
It's a MK1 1.8 GTi DX engine with KJetronic.
Has anyone had this issue and successfully resolved it?
This is the relay I bought. 

Everything you need to know about manufacturers of relays is here:

https://www.cabby-info.com/files/electrical/Relays_Kjetronic.pdf

Actually the Fuel pump relay cycles with the timing, that is it is turning on an off by the Coil.

When the car is ready to fire the relay pulses,
It is usually happening so fast that is appears to stay on.

The fact that you can hear the relay run, I suspect that you need verify the connectivity (cleanliness of your wires on the coil and or the grounds on your car.  I am not saying that you didn't get a wonky relay that is still a possibility. I am saying that you need good grounds as one of the big killers of them is overheated connections.  I would also verify and clean your connections on your Pump and other electrical components in the fuel system.

If you haven't replaced your main grounds on your car you may want to do so before trying to trouble shoot electrical issues.

The Unshielded OEM wires if still present are probably not electrically viable.

That is battery to frame and frame to engine.
 

Thanks for that info and I'll take that onboard and address that info first. I fitted the pump and accumulator and the wiring to it so I know that's all good.. I'll run thru the earthing and see what improves… Thanks again👍