Fuel Pump not Priming - Possible electrical issue?

[beeby11]

Afternoon all,

Just after a bit of advice before I go buying a new fuel pump for no reason.

When turning the key there is no noise coming from the fuel pump, sometimes it does some times it doesn't there is no real pattern. Sometimes it will kick in as the key is turned other times it will just prime by itself. As soon as the fuel pump primes which I am guessing is the noise the car starts and runs fine.

The car has not yet failed to start however it does take a while and is beginning to get annoying.

I believe the ignition switch was replaced before I bought the car, so I don't think it is that. I have a multimeter to go over the wires to the fuel pump but I am not sure it is an wire issue as I would expect the problem to persist once the car is running?

I am just after any other avenues or possibilities to look at as after looking at prices for fuel pumps it seem cheaper to get the diagnosis 100% right before going and buying a replacement.

Any help appreciated.

Many thanks

Andy

[PeteG40]

i'd say either of the relays could be at fault - ecu or fuel pump relay.  They are located next to the ECU

[beeby11]

Any idea off the top of your head what numbers they are? If not I have a manual so I assume they will be in there

[C0UP3]

Had this issue with my gt. I was the 5pin ecu relay which is under scuttle tray on passenger side. Only places I could find for a new one was max rpm or vw heritage.

As a start though get some contact cleaner and spray the relay pins and the holder pins for the relay as they corrode causing the relay to stress then blow

[beeby11]

I appreciate the replies guys i'll take a look at the relays when I get home.

Many thanks

Andy

[AdzCM]

I'm having the same problem. Found this interesting for future reference.....

http://www.clubpolo.co.uk/forum/index.php?showtopic=275393&page=2

It talks about modifying the holder to fit this:

http://www.ebay.co.uk/itm/VW-GOLF-MK3-GTI-2-0L-8V-16V-ECU-RELAY-165906381-C142-/201020528002?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2ecdc1d582

[Etches]

I had the same problem at one point, on of my relays had melted lol

[beeby11]

Evening all,

Again thanks for the replies, i have just gone out and had a check over the relays the bottom of the two (53) which i believe is the one for the fuel pump seems to look ok - no rust on the pins or in the holes. I gave it a bit of a quirt of WD40 for good measure.

The relay on the top (doesn't have a number, just silver) seems a bit melted and scabby but i didn't think this was anything to do with the fuel pump. I stand to be corrected though. I gave it a bit of WD40 but made no difference.

Etches where did you get a new one from?

Many thanks

Andy

[C0UP3]

Was it the 4pin one or 5pin one that was crusty? 4 pin is easy to get that is the fuel pump relay. Gsf couple of quid.

5pin is the ecu relay (which will stop fuel pump priming) more difficult to get but can be had for around 25quid new

[beeby11]

Hi COUP3

It was the 5 pin that was a bit iffy, don't suppose you have a link to them at all do you? From reading the links above i get the impression they are not that easy to come by.

Thanks

Andy

[bradderss]

Had a similar problem when converting my MK2 to a G40.

Fuse number 20, the seperate fuse outside of the plastic box, is for the fuel pump.

Mine at first looked fine but after a few in's and out's the fuel pump primed each time. Perhaps try that as the connection might not be quite good enough?

You can check if power is getting to the fuel pump by using a multimeter on the fuel pump plug under the rear of the car and turning on the ignition to see if this is getting power at the usual priming stage. If there is no power then the problem is with the relays or fuse.

If there is power then I would look at the pump under the car and perhaps the plug connection on the top of the tank under the rear seat.

Good luck!
 

[C0UP3]

Maxrpm have them. Or if you get part number vw heritage can get them. Also saw them on eBay as well. Find the part number and there not impossible to get but u may need some patience or get lucky

[beeby11]

Evening gents,

Just had another little look at the G40. I dug out some 20 fuses and changed it over, surprise surprise no difference, that would be too easy.

I pulled the relay again and wouldn't mind some opinions on it, broke or not broke? - pic below



Many thanks

Andy

[randombadger69]

Did you try the multi meter on the fuel pump?

Another way to check is to run 12v to the fuel pump directly. If it works then it's definitely not the pump.

I'd put at least 20p on it being your Ecu relay.

Happened on a standard g I bought not long back, firstly blamed the ignition switch, then the immobiliser, then once I'd removed that back tracked and found it to be the Ecu relay at fault.

[Jezza-7]

If you need one of them fuses still, let me know as i think i got about 2 or 3 of them.