K series fuel pump

[Toby S]

Hi All

Changing my in tank fuel pump in a 1992 1400 K series Supersport.

See pictures below - I've currently just slotted the new pump into where the old pump came out - does anybody know what the purpose of piece between the pump outlet and the fuel outlet on the access cover which screws onto the tank (effectively the black box with the 2 gold bells on in the pictures) and whether it's necessary - looks to be some sort of regulator/reservoir, although the new pump came with a fuel pipe and 2 jubilee clips which could be used to join the pump and the tank outlet instead of the funny looking unit.

The old pump looks to be an original dating back to to 1992 (can't see the make) and I'm replacing it with a Walbro GS242 pump which I managed to source from Redline. 

Currently wondering whether to use the old connector referred to above or simply join the pump and the outlet with normal fuel hose.

Any advise on what the connector does or whether anybody has just used hose ( and the results) or has any thought on the matter would be most welcome 

Cheers

 

[garybee]

I have no idea about what has been included with your pump (if it's suitable for in-tank use) but you can't just use any fuel hose inside the fuel tank.  All but the hose sold specifically for in-tank use turns to jelly after a short time.

edit: too specific

[7 wonders of the world]

All the pumps I've used come with a short length of hose with them, I used O clips though rather than the cheap worm drive ones in the kit.

You sometimes have to re engineer the pump holder too either plastic ring or trim the rubber coller.

[Toby S]

Hi all

Thanks for the point raised

It is definitely an in tank replacement pump

Already had the Dremel going to shave the inside of the pump holder (the white plastic bit in the picture in which the silver pump sits) to get the replacement pump to fit - as advised by Redline, who were really helpful and it now fits together nicely.

It's the unusual looking connection between the pump and the exit pipe which I can't understand what it does, although I take on the hose point above - thanks - the hose supplied incidentally looks like thicker grade meshed fuel hose - quite solid.  My only thoughts is that the unit referred to serves as some kind of reservoir holding a small amount of fuel for when cornering on a very low tank where the fuel could sloosh to one side potentially causing the pump then to draw on air - I could of course be wrong (I'm no engineer) but really interested to know what it does and whether its needed.

Also worth noting for anyone else thinking of going through a change of fuel pump, the electrical connection (black plastic connector which passes through the larger hole just above the red wire in the circular plate which bolts onto the fuel tank in picture 2 in the original posting which is the large black electric connector visible from outside the tank, as well as the white electrical holder which attaches thereto inside the tank as well as for that matter the round access plate itself and the whole pump holder assembly are no longer available anywhere (Redline, Caterham, Rimmer Bros and a number of other motor factors and electrical component suppliers I tried) -  no longer manufactured apparently - was off a Rover Metro. Take special care of these parts as you may not find replacements and may find you will have to change the whole tank set up if these are damaged. I've had to do a fix on the sealed black electrical connector referred to above which was in very bad shape and where loom  connection had been lost - ended up having to drill out old resin down to the pin connectors and then solder new fly wires in to connect to the loom and then made water/petrol/spark tight with non acid based silicone - a DREMEL  seems to be getting a must have tool with an older Caterham !!

BY the way Top Tip  if you're investigating a non working fuel pump issue - from experience over the last week I'd recommend not trying to pull off the large black electrical connection visible from the side of the tank without first draining the tank - You'll find you'll only mange to pull out the whole of the electrical connection out of the tank and be left with a gaping 1/2 inch hole and covered in petrol - Mmm lovely with my head  6 inches directly underneath!!

Back to original question - anybody any ideas what the black plastic unit with gold bells on it does between the pump and the exit pipe ?

[revilla]

I'm sure I wrote an answer yesterday but it doesn't seem to have been posted, probably user error! The gold part is a pulse damper, it smooths out the pulsating flow from the pump to give a steady supply pressure on the other side. I've no idea how critical it is but it was part of the original Rover (Metro?) installation. I've got all the part numbers written down somewhere.

[revilla]

A bit about it here, plenty more via Google: https://injector-rehab.com/shop/fpd.html

[7 wonders of the world]

think the fuel filter and pressure reg will damper out any pulses....... mine was a p1ss fit so I replaced it with the hose in he kit and a pair of O clips.

[Toby S]

Thanks Revilla

Did the google search as you suggested and it seems the choice is to remove and risk knackering your injectors or leave in and risk catching fire if it fails - Hmmm

Seems a likely candidate topic for a foam sump baffle mk 2 Blatchat debate.

Given it was there in the first place I think I'll leave in -  when I first lifted the tank plate holding the pump and saw uninsulated spade connections to the pump on both red and earth cables I was a bit shocked too - given these would have been either sat in fuel on a full tank or worse still petrol vapour on a 1/4 full tank, with the tank venting air through the a pipe off the filler nozzle, it seems to have survived 27 years without blowing up thus far

 

 

 

[revilla]

It's only going to catch fire if it fails where failure leads to a fuel leak. If it's in the tank it will be fail-safe. The ones linked with fires are external and can leak in the engine bay. I've not heard of them being points of failure. I would just leave it as it is.

[revilla]

And don't worry about the connections. The wiring and pump are safe in the tank because the air-fuel mixture in there is actually far too rich to burn, almost entirely fuel vapour. Even if you get sparks off the connections, the pump motor, the fuel gauge sender - it won't go up in flames.

[Toby S]

I guessed that to be the case - just a bit of a shock when I saw the open connections

Thanks for all help and advise Revilla