Gti Fuel Pump Relay & associated wiring diagrams.
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Gti Fuel Pump Relay & associated wiring diagrams.
My questions are should the pump prime itself briefly when the ignition is switched on like in a K-jetronic Escort or does it only run when cranked?
What activates the fuel pump relay, is it fed purely from the ignition switch or is there a speed sensing relay that operates it in turn?
Is my relay knackered?
Where can I find a suitable wiring diagram, I have a Haynes Golf manual no726 but I don't think the diagrams correspond to the late loom?
I have tried to search but it's all been a bit vague so any help is welcome!
Posted
MOTY 2013
if you look in my sig at the jetta89.pdf that shows a pre-90 mk2 diagram which is mostly the same as yours, though obv not 100%.
to check for a relay issue swap a #53 relay into the fuel pump relay socket, this will make the pump come on with the ignition which isnt safe but it will let you rule in/out the pump relay
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
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My wiring diagrams and other documents have moved here:
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You'll need to sign into google/gmail for the link to work! (its free!)
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I've just ordered one of the Bentley Publishing manual's which I hope will cover my model in more detail.
I'll try that 53 relay swap as a matter of interest tbh!
Posted
MOTY 2013
my theory on the prime is on some cars when you switch on the ignition you get a single spark from the coil, though im not sure exactly what causes this. this spark in theory would send a rev pulse to the fusebox which would in turn make the pump relay switch briefly
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
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You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
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Fuel pump electrics is the problem again so need to try to understand what's going on, pump has started to fail to prime again periodically, when this happens it usually fails to start so it obviously doesn't run when cranking either. Usually a quick fiddle with the pump sorted it but yesterday I had a nightmare trying to get it to run. Even with the cover off the relay, closing the contacts manually failed to get the pump running. At this point I started to check other relays that clicked when priming the pump, found that the one next to it which I believe is the Load Reduction relay had some corrosion on its main pins into the fusebox, cleaning these up seemed to solve the issue, fuel pump now primed?
I've tried to follow the diagrams I have but can't for the life of me follow them to any conclusion as they're so disjointed.
i saw one suggestion that was to remove the relay wiring from the fusebox and have the relay loose, is this likely to help?
Whats the the wiring relationship between the fuel pump relay and the load reduction relay, is it possible this was the problem? Can't find a diagram that shows ant hung useful tbh?
Posted
MOTY 2013
if your car is runnign digifant then it should always prime the fuel pump with ignition on, I was assumed it was kjet but since its a 93 i shouldnt have
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
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You'll need to sign into google/gmail for the link to work! (its free!)
Posted
MOTY 2013
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
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What's a 53 relay?
When I try to open the links on your sig it just takes me to a Google docs page, no docs showing though?
Posted
MOTY 2013
you need to sign into google or gmail, plus use android or windows devices as apple products dont seem to work! try this direct link anyway:
jetta89.pdf - Google Drive
once open you'll see the kjet relay uses circuit 15 for ignition trigger plus pin 5 for the rev counter signal from D/26.
The x-over relay uses a feed from ignition switch to power circuit X, which isnt used by the fuel relay so I cant see how jumping it would help
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
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You'll need to sign into google/gmail for the link to work! (its free!)
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I've just been down to the car (its in storage) and lo-n-behold, pump wasn't priming & wouldn't start. I looked at the load reduction relay (henceforth known as the LRR!) tried with it removed and fiddled with it a bit. i was then able to get the pump to run, removed it and pump still ran. This lead me to believe it wasnt the relay but I was affecting something else when I removed/replaced it, so I investigated the fuses below and found Fuse #5 was all but falling apart. So there was no issue with the LRR, it was just that as i fiddled with it I disturbed the damaged fuel pump fuse at the same time. I found a spare 30amp fuse (i know it should be 15amp but that was all I had, will replace later) and now fuel pump can be run at will by closing the switch on the FPR!
What I would like to do now is replace the wiring from the output of the relay and run a seperate fuse bypassing the fusebox and going to the fuel pump as I suspect the fusebox itself is damaged as well as the busted fuse. I cant see the back of the fusebox, is it wired between the relay and fuse or is it done on busbars? What's the best way of curing this permanently?
Posted
MOTY 2013
the wiring on this all goes via 4 main plugs on the fusebox, no busbars so you'll have to find the rev counter wire D/26 and tap into it, plus the fuel pump power E/14. live, earth and ignition live easy peasy. the fuel relay uses larger 9.53mm spade terminals so you'll need to source those. ideally find a VW relay holder in the scrappy, MK3 golf are ideal source for large spade relays as they use 2 of them for the ABS system.
You'll need proper uninsulated latched spades plus a good crimping tool to do this:
Auto Electrical Components, Parts and Accessories for Trade and DIY: Polevolt Ltd
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
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I may also add a second relay, I did this on my Escort RS turbo, added a second relay in parallel so current was halved through each one, worked a treat. As the pumps get older they draw more current than the old wiring can take.
Posted
MOTY 2013
as i say ideally change the fusebox as it could have other damage, you shouldnt need to add a relay as the factory setup is capable. if your fuel pump is drawing too much power it will need replacing as its likely to pack in soon! have you checked the lifter pump is still working, this will cause main pump to strain and eventually die
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
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How do I go about checking the lift pump? Tbh might just replace both anyway. I'd rather replace stuff before it fails as once the car starts to become unreliable I'll probably never use it!
Posted
MOTY 2013
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
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What are the best pumps to get, genuine Bosch hi-pressure pump and Lucas lift?
Posted
MOTY 2013
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
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