Fuel Pump, help needed!

[joedirt]

We have just bought a new electric (pointless?) fuel pump as the old one was making a rather horrific noise, I have replaced it in exactly the same way as i took it off but now the new pump appears to be doing nothing. We have tested the new pump straight from the battery and it works nicely but once wired into the car it stops.

This seems to me like a wiring fault but its hard to diagnose properly as the previous owner has obviously done some "home wiring"....looking through the manual it shows the pump being earthed to the body??

The pump now has a white wire coming through the firewall along with others that appear to have been one insulated loom (split open and messed with now by previous owner)...this white wire connects to the positive terminal on the pump..

The negative terminal has a black wire that runs to an iffy looking connection block and this then goes to the wiper motor...oh lord...I have stripped the block and re did all the connections to ensure its as good as it can get.

is this right in terms of earthing the pump?...should i get rid of this and earth the pump to the body myself? I still need to check to make sure there is power at the white wire which i will do this weekend.

the other problem is that we have replaced the battery and the positive wire, I'm assuming this car has been converted to negative earth in the past as the battery goes on regular way. The car ran and started with it this way and its trying to start now albeit with the fuel pump problem which i'm hoping is the cause...

What we did notice though is that when you turn the ignition and pull the starter there is some sparking from the earth lead to the battery, is this simply a bad connection or worn lead or is there something else wrong?

I have to admit that i dont work on morris's that much so i'm baffeled by the whole negative/positive earth situation...I am tyring my best though to get this car running well as its my girlfriends and shes really looking forward to using it!

Any help on these matters would be greatly appreciated.

[bigginger]

The power to the pump runs down a white wire, and is earthed to the body by a "dark" wire. I'm guessing that the connector block is a common earth that somebody has added, and is pretty likely to be the problem. If you're getting electricity from the white wire, connect the earth direct to the bodywork. Then work out what else is earthing through the con block and earth them properly too.

I realised this morning that what I'd written was a bit misleading, so I've edited it and just want to stress that the pump is NOT fuse protected

[bmcecosse]

But the sparking from your earthw ire is a big worry! If there are any petrol fumes - or hydrogen from the battery - you are well in the running for a fire. Sort out the earth lead right away. Are you sure the new pump is not working - I understand they are very quiet - and if it' s new it may have pumped up the fuel and is now waiting till more is needed. Take the hose off the carb and direct it into a can - now switch on and see if any fuel comes through. The SU pumps are earthed through the body where they bolt on - and there is usually an additional earth cable just to make sure. I assume the new pump will be the same - but just make off a good earth direct to body anyway.