Fuel pump relay & fuse box

Looking for help on this one.
Campaign on EW chassis no. with relay 321906059F. Car wouldn't run; fired and died immediately. Replaced fuel pump relay and it ran OK briefly then wouldn't fire at all. Then it ran with the original relay once but that was it.
Replaced fuse box which had green crusty bits in it; no difference.
Got another new relay and it will now run on tickover but any attempt to raise revs brings rapid rising and falling of engine speed accompanied by loud ticking from the fuse box.
It's as if something's telling it "you'll get fuel at 800 rpm but no quicker".
Neither of the old relays now works at all but the car did run OK if you took the relay out and bridged the slots in the fuse box.
Any advice much appreciated.
Cheers.
 

Have you checked how much current is being drawn by the fuel pump - this can tell you how hard the pump is having to work - if it is being stressed (and therefore pulling a lot of current), perhaps not enough fuel is being delivered to do more than run at idle?

Hope this helps

LeeO

I had a similar problem and I ended up taking out the fusebox, opening inside it and cleaning all the terminals properly. This cured it. Not a major job and will also eliminate the fusebox for problem solving for the next irritating fault that happens.

try a 17, 18 or 100 relay in the fuel socket. if car runs great then either you have duff relays, the fusebox is bad, or the rev counter wire from the coil -ve is to blame

Thanks everyone for the advice. Had an auto electrician to check it all over; he reckons wiring is ok and fuel pump and rev counter ok. It'll run without a relay and it'll run with a simple relay that means - I think - that the fuel pump is running all the time the ignition is on. I returned the last replacement relay but the new one is just the same - primes pump, starts, runs, but won't rev and ticks all the time.
The rev counter works ok but I'm not sure that the yellow light comes on at >2k ; can't go on road as it's SORNed but I thought it used to when going in and out of garage so is this a clue? + can all these relays be faulty?
Thanks again

the stock relays need a rev counter signal to work, it may be the terminal in your fusebox for this is corroded/worn or the track inside the fusebox from the pin to relay socket is deamaged so the relay cant get a good contact.

If as you say a normal switched relay runs the car just fine then you know the other relay terminals in the fusebox are all fine as are the fuel pump and wiring to it

Thanks very much for that - following from what you say about the stock relay,  I've got another relay on order which is supposed to be a proper VW one; didn't know you could get these but VW Heritage say it'll be here soon. This will cure it!

And it works!!!!
'Stock' is the keyword - seems the pattern relays are both faulty or just don't work on my  car for some reason.
Anyway, couple of jobs to do, get it MOT'd, off SORN and back in business.
Thanks again

David said

And it works!!!!
'Stock' is the keyword - seems the pattern relays are both faulty or just don't work on my  car for some reason.
Anyway, couple of jobs to do, get it MOT'd, off SORN and back in business.
Thanks again

cool another toy on the road