Mk 1 gti wont start

Hello people
     I have been trying to get my mk 1 going, it used to start no problembut since it has benn tweaked at vw by the techs there it doeasnt want to know. It could just be coincedence. There doesnt seem to be any power going to the fuel pump, i have put a meter on it and turned the ignition on but nothing, the relay does click when you first turn the ignition on but i dont hear the fuel pump prime( is it supposed to ?). Also i have took the fuel return line off and cranked the car and no fuel isgoing through, there is a spark as i have removed a plug and turned the key with it back in the lead and it sparks ok. Aso i have took a live 12volt feed direct from the battery to the fuel pump and it primes and runs fine, could it be the fuel relay or the coil or something else? I believe the coil has to send a signal to the fuel pump when the ignition is turned to crank, is this signal sent from the relay to the coil to the pump or another way?also is there a seperate fuse for the fuel pump? The relay does not have the piggyback fuse on it.sorry for all the questions but this is driving me potty.
cheers
Daz

Hi Daz, sounds like the fuel pump realy to me, its been a while since mine was on the road, but i seem to remember there is a little trick you can do as a get you home solution if you know what i mean. either above or below the fuel pump relay you will find another relay, when turned by 180 degrees has a similar pin set out as the fuel pump relay. when inserted where the fuel pump relay was, it will run the pump continuously, this will prove if it is the relay or not. sorry to be a little vague, but its been a while!!
Maybe someone on here can confirm which relay it is.

Cheers

Rob

Cheers rob, that's the sort of thing I need to do yes to prove the fuel relay is defective, I don't suppose it could be the coil?

My relay went a month or so ago. Try squirting some quick start in to the throttle body. If you get some action it would suggest a fuel issue. I then crimes some female connectors on a short length of wire a slipped them in, in place of the relay. And it worked.
If you think it's the coil, whip out a spark plug and whilst still connected to the ht lead rest it on the engine block. It shoul still spark when turned over.

It's still sparking yes, the fuel pump runs with a permanent live to battery, could it just be the fuel relay as it was running like a new car before this? I will pull it out again tommorow and have another go.

If its the late blade fusebox you have, swap a 17/18 relay into the pump relay socket. that should make the fuel pump come on with the ignition. if the car starts and runs with this relay then yes, your relay is dead or the rev counter feed to the fusebox has gone (if rev counter works its not that) could also be the fusebox itself, so check it carefully for water damage

if its early ceramic fusebox it could be the fuel pump power pin has melted, this is a common problem as its under spec for the loads required. a vw factory recall involved mounting the relay above the fusebox, but the kits are NLA now so you'll have to make your own

rubjonny said

If its the late blade fusebox you have, swap a 17/18 relay into the pump relay socket. that should make the fuel pump come on with the ignition. if the car starts and runs with this relay then yes, your relay is dead or the rev counter feed to the fusebox has gone (if rev counter works its not that) could also be the fusebox itself, so check it carefully for water damage

if its early ceramic fusebox it could be the fuel pump power pin has melted, this is a common problem as its under spec for the loads required. a vw factory recall involved mounting the relay above the fusebox, but the kits are NLA now so you'll have to make your own

Ok we have life lol, yes mate good shout the car starts but won't run, now I think I know why. I have been a clutz and adjusted the co like an idiot because I thought it was down to it bring adjusted that it wouldn't start, so my next question is, is there a basic setting that I need to do to that Allen screw in the top of the metering head. I know I shouldn't have touched it but frustration and all that , also where is the best place to get a fuse pump relay? Oh and the rev counter works fine.

pump relay can be had from gsf, co screw you'll just have to fiddle till it works there isnt really a generic setting you can put it to

rubjonny said

pump relay can be had from gsf, co screw you'll just have to fiddle till it works there isnt really a generic setting you can put it to

Much success, got it going and ticking over, managed to adjust the co screw, don't know if it was by luck or what. Relay 17 appears to be the wiper motor as this wasn't working when I had it running. Just need to get a fuel pump relay now, thanks people. Happy times.

Sounds similar to my issue so im going to nick this post lol and hope i too have happy times ahead

Guyred said

Sounds similar to my issue so im going to nick this post lol and hope i too have happy times ahead

No problem mate, good luck with it. My new relay should be here today or tommorow so I will confirm it was that when I fit it. 

relay 17 powers the lights, wipers, blower motor, horns etc its job is to cut power to all the power hungry stuff while you crank it over on the starter.

it just happens to be the right pinout to fit a fuel pump relay socket plus it has the large pins you need for the power in and pump out. a std switched relay will also fit but the pins are too small, though you can sometimes get away with it

rubjonny said

relay 17 powers the lights, wipers, blower motor, horns etc its job is to cut power to all the power hungry stuff while you crank it over on the starter.

it just happens to be the right pinout to fit a fuel pump relay socket plus it has the large pins you need for the power in and pump out. a std switched relay will also fit but the pins are too small, though you can sometimes get away with it

Ok try and work this out, I have changed the fuel pump relay and the car starts and runs, I took it for a quick blip round the block to check as I want to get it mot'd next week if I can, wiper wash was a bit reluctant to work but with a bit of movement to get the connections sorted in the wiper arm on the column it's ok now, the only thing is, and don't ask me why I did it because I don't know, when driving and you press the horn the car stutters, could it be an earth problem?  Don't remember it going it before

yeah i would say so, check all the brown wires behind the fusebox for corrosion. there should be a chunky brown from the battery start there and work your wat back. dont forget the earth claw above the fusebox