Fuel pump woes

doodle bug · May 9, 2024

Hello all.. I decided in my wisdom to renew the fuel pump on my 1990 r/r 3.9 efi classic ! BUT the one i bought supposedly for that vehicle does not work ? ( thank you Britpart ) does anyone know the make / part number for the correct one as the britpart one is nothing like the original .......ps if i had half a brain i would have taken photos but due to needing the vehicle straight away i put it back in

doodle bug · May 9, 2024

just found a picture in the Haynes manuual of the original pump !

cappers · May 9, 2024

I have a 3.5 hotwire efi from a 1992 Disco 1 (so similar efi wise) in my Landy and used this in-tank fuel pump for a RRC - PRC8318.

The add states "Suitable for ALL Range Rover Classic V8 EFI vehicles up to 1990 approx (up to chassis No; GA464553)".
(I had to shorten it a little bit to fit a 90 tank but should be fine for a RRC tank).

https://www.ebay.co.uk/itm/261202611181

discool · May 9, 2024

For the classic RR, PRC7475 up to Vin GA414221 & from Vin GA412223 PRC3818.
Nothing shown for the HA Vin in my 724 parts book

Only one number for the 3.9 VA Vin disco PRC9409

doodle bug · May 10, 2024

cappers said:
I have a 3.5 hotwire efi from a 1992 Disco 1 (so similar efi wise) in my Landy and used this in-tank fuel pump for a RRC - PRC8318.

The add states "Suitable for ALL Range Rover Classic V8 EFI vehicles up to 1990 approx (up to chassis No; GA464553)".
(I had to shorten it a little bit to fit a 90 tank but should be fine for a RRC tank).
View attachment 316737

https://www.ebay.co.uk/itm/261202611181

Thats the same as i bought ! it doesnt work and my chassis number starts at GA4501767''''''''''

doodle bug · May 10, 2024

Thank god mrs doodle took a photo ! the one on the right is the original the left one is the new one ..

norseman · May 10, 2024

This has become a problem with parts for old cars, not just LR products.
So called 'genuine' components have long since been unavailable (even to those owners that could afford to pay the premium prices) so aftermarket suppliers make a killing by satisfying demand.

Nobody knows where such components are manuf. or the level of quality control applied.
Having said that I've had a few 'genuine' items, mainly ignition components, that I've returned to the supplier(s) as being totally inferior.

They don't make 'em like they used to

cappers · May 10, 2024

doodle bug said:
Thank god mrs doodle took a photo ! the one on the right is the original the left one is the new one ..

That looks like a PRC7491 for Triumph/Rover V8 Sender & pump, but I don't think they are available anymore.

doodle bug said:
renew the fuel pump on my 1990 r/r 3.9 efi classic ! BUT the one i bought supposedly for that vehicle does not work ? (

What do you mean by "does not work"? Doesn't fit or doesn't run or runs but doesn't pump properly?

doodle bug · May 11, 2024

cappers said:
That looks like a PRC7491 for Triumph/Rover V8 Sender & pump, but I don't think they are available anymore.
View attachment 316791

What do you mean by "does not work"? Doesn't fit or doesn't run or runs but doesn't pump properly?

When I finished fitting it I plugged it in and got nothing ?

Last night I borrowed another new one from a mate and got the same results ! Refitted the old one and it runs perfect... I've a feeling things are going to get messy unless I can find a decent S/H one

Datatek · May 11, 2024

doodle bug said:
When I finished fitting it I plugged it in and got nothing ? Last night I borrowed another new one from a mate and got the same results ! Refitted the old one and it runs perfect... I've a feeling things are going to get messy unless I can find a decent S/H one

When you say "got nothing", do you mean the motor does not run? Or the motor runs but no fuel??
I know nothing about the Classic, but the motor should run on the pump even if it's the wrong one. If the motor runs but you get no fuel, it could be that the polarity is wrong for the new pump so it's running backwards hence no fuel.
As a last resort, you could leave the old pump in place and fit a suitable FACIT pump in the fuel line under the bonnet.

Ratae · May 11, 2024

Connect the new one to a battery & see what happens.

doodle bug · May 11, 2024

Ratae said:
Connect the new one to a battery & see what happens.

good thinking Batman !

Hicap phill · May 11, 2024

Ratae said:
Connect the new one to a battery & see what happens.

Of course watch the sparks off any battery terminals & petrol…. Can you get someone to video for us all to chuckle at later?

Ratae · May 11, 2024

Hicap phill said:
Of course watch the sparks off any battery terminals & petrol…. Can you get someone to video for us all to chuckle at later?

Ah, my mistake. I assumed the OP might have a modicum of sense.
But in this day & age that's perhaps not the best assumption

doodle bug · May 11, 2024

Ratae said:
Ah, my mistake. I assumed the OP might have a modicum of sense.
But in this day & age that's perhaps not the best assumption

I went one better ! I got the Mrs to do it so i could have a chuckle as well later

doodle bug · May 11, 2024

Update ! .........tried it on a battery and the pump runs ! reached under the wheel arch and connected to the feed and it stopped I wriggled the connecter around and it started again !!! seems like i,ve got bad earth problem somewhere

Ratae · May 11, 2024

I had something very similar with my own - 1986 3.5EFi - which turned out to be the live feed wire.
Old pump had failed - lots of noise before it died.
Fitted the new & nothing.
Bit of head scratching & out with the digital multimeter.
Almost battery voltage showing at the connector in the wheelarch but still no run.
Traced all the way back to the fuse & still OK voltage.
New pump ran fine when connected to a separate battery & the car started. (Didn't manage to blow myself up

)
Decided to check the live at the connector in the wheelarch with a 12 volt bulb.
Nothing, not even a glimmer.
Checked along the wire using a pin to pierce the insulation until the bulb lit.
Which was about an inch up from the connector.
Turned out that 30+ years of exposure to the elements had caused the wire to corrode away to just a couple of strands inside the insulation, enough for a digital MM to show the expected reading but not enough to pass the current required.

ETA I did have fun with a previous pump (might have been the one that failed) after fitting a new tank some years ago - old one had corroded through at the seam.
All fitted & fine until I ran the fuel down to where I would have expected the low warning light to come on.
The low warning light did indeed come on & very shortly afterwards the car slowly came to a stop - fortunately not on a busy road.
Puzzled as I knew I could get at least 30 miles after the light came on with the old tank & putting a gallon in had restored normal service.
Pulled the pump & measured the depth of the tank from the hole. Slightly deeper than the old one.
Examination of the pump showed that there was some adjustment & that solved the issue.
I spoke to the supplier & we measured the other tanks he'd got in stock. No two were identical!

doodle bug · May 12, 2024

Thanks to everyone who replied ! ...and i,ll pass your kind regards on to Mrs Doodle when they release her from the Burns unit Bless her large armour plated doodle proof knickers !!! :vb-angel4:

Fuel pump woes

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