Fuel pump relays

bRought a GSF pump relay and it primes twice on my gti, but tried a VW golf gti mk2 genuine pump relay and it fires up just the same, methinks the engine don't know any different?

I was reading an article in Golf+ by the tech guru ! He said the MK2 relay has a self prime facility the Mk1 does not . Mine has a non fused [top of relay] mk2 type and it self primes . Supposed to assist starting .

   :dontknow:

Are they the same part number ?

I don't know Chudd neither, but what i do know is that you can hear the GSF pump relay prime twice, yet the VW golf gti mk2 relay is silent, yet starts justs the same.

mine primes sometimes and others not.

now its not priming at all.

i'm beginning to think i need a new fuel pump

this thread here…http://www.vwgolfmk1.o…viewtopic&p=229439#229439

..but does it still start?

start then cut out... might be using vapours in the line?, read my thread.... gonna get it checked tomorrow as time is of the esscence at the mo

Funny thing is, I have experience of 4 cars: on 2 of them, the fuel pump primed once (on ignition on but not start), for around 4 seconds, then stopped (until the starter motor turned). On the other 2, as soon as the ignition is on (not start), the fuel punp was running. No idea of the history of the relevant relays, though.

Paul, with my mk2 gti relay in, the car starts yet no noise, how strange??

golf1 said

Paul, with my mk2 gti relay in, the car starts yet no noise, how strange??

A decent fuel pump and clean fuel doesn't make any noise.

Humm.., I'm not so sure.

golf1 said

Humm.., I not so sure

Well, I have worked on plenty of Mercs with K-Jet and the fuel pump is almost silent.

paul_c said

A decent fuel pump and clean fuel doesn't make any noise.

Low hum for a few seconds can be heard on switching on the ignition [buzz] i always wait for it and then can guarantee engine will fire when starter turns .

paul_c said

golf1 said

Humm.., I not so sure

Well, I have worked on plenty of Mercs with K-Jet and the fuel pump is almost silent.

Point taken, but in my case the GSF pump relay can clearly be heard priming twice with the car door open, yet the VW mk2 relay is silent, strangelyy the VW mk2 relay starts up just the same. As with your thinking it's very strange indeed and can't really be understood.

golf1 said

paul_c said

golf1 said

Humm.., I not so sure

Well, I have worked on plenty of Mercs with K-Jet and the fuel pump is almost silent.

Point taken, but in my case the GSF pump relay can clearly be heard priming twice with the car door open, yet the VW mk2 relay is silent, strangelyy the VW mk2 relay starts up just the same. As with your thinking it's very strange indeed and can't really be understood.

If its the same fuel pump and the same car, but a different relay, your right, its confusing. The only possible suggestion is maybe, that a sliver of rust/dirt entered the pump one day, and the next day it didn't…..

The noise can only be 2 things: cavitation within the pump, or mechanical noise eg from the bearings. The mechanicals would wear over time, not magically fix themselves….right?

Talking seconds with switch overs on relays and noise. I can't understand it, really.

Thought I would post this, I've tried a mk3 pump relay and it primes once and the engine cuts out afer 1 minute, must be something to do with the internal workings.

I've got the same problem with my 1600 gti.

Car starts but cuts out more or less after a few seconds.

On turning the ignition key the pump does appear to be very noisy tho. Do you think this is due to it being past it ?

Pump noisy means the relay's working. Take off and inspect the fuel pump ( 5 minute job to remove pump) clean out as necessary. I checked my pump off the car and used thin 3 in one oil instead of petrol to test the flow.