Car Wont Start

[futura 3]

You must have some wiring problem. For the fuel pump to draw such a current that heats the relay to 230 Celcius (solder melting temperature), there must be some kind of shortcut going on, and I would expect it to come from the wiring in the first place, rather than the fuel pump itself?

Edited September 22, 2006 by futura

[mickie 3]

i have no idea if its had some sort of short cut put in, all im going off so far is people going into detail with me of how a fuel pump not functionining properly would draw a lot of current through the relay causing it to over heat then pop

 

i would love to under stand how a short cut wire would over heat the relay in detail as the car had been running when i bought the car, it wasnt the best and it didnt idle well but it ran..

 

after ive rebuild the engine all wires have gone back in the same place, all earths are fine, maybe the solder i have been fixing the relays with have a low melting point ?

[mickie 3]

ive been looking through the wiring diagram and ive found out their is a wire that come off my starter motor and that is supposed to goto the techy relay, ECU and some other place i dont know of, anyway that wire has been replaced with a purple one, if that hasnt been put in right would that over heat the techy relay ?

 

i dont get how a fuel pump can over heat the techy relay when its fused before it gets to the relay

also is their a fuse for the relay ? or does it get its live straight from the battery ?

Edited September 23, 2006 by mickie

[luggy 13]

Hi mickie

Good effort on your perseverance, just had a look at my starter setup, only thing connected to mine is the Pos from the battery and lead to the ignition. Might be an idea to disconnect that purple wire and give it a go. I believe there are 2 circuits on the starter motor. 1 is for the solenoid to engage the starter and 2. for the motor itself, this is because because the amount of juice going through the starter motor is quite high thats why its seperate. Dont know if this is any help. Good luck

 

Luggy

[mickie 3]

cheers luggy, if i dissconect the purple wire from the starter motor the motor just runs and runs, i really dont get why its been replaced with this random purple wire tho, maybe they couldnt find the black cable right next to it for all the oil at the time.. could this cable overheat the relay tho ?

http://img.photobucket.com/albums/v649/mic...ti/Image026.jpg

 

their is a constand live to the techy relay which is always on and isnt fused, i think thats quite mad, why isnt it through the ignition and fused ?

 

im think about fusing that live with a 15amp fuse, is that the right size fuse to use ? good idea ?

 

if i want to connect the fuel pump up direct what colour is the fuel pump live at the relay connector block ? because i could connect that up to #20 brown cable couldnt i to make the fuel pump work ?

also i dont have a clue what sort of current should and shouldnt be running through any of the cables for the techy relay, does anyone else ?

 

sorry if im boring anyone but all i want is to know how to fix it and maybe prevent it happening again

Edited September 24, 2006 by mickie

[welshpug 1,657]

the only place that purple wire should go is to the brown multiplug.

[futura 3]

It looks to me that the previous owner of the car has fiddled with the wiring.

The purple cable that is (poorly) wired to the starter motor from your ignition is there to solve some starter motor problems. I don't think it has any influence on your tachy relay getting knackered.

Replacing your brown multiplug and rewiring the starter motor through it is something you can add to your list of to do things for later.

 

For now, I would find someone local to you who owns a GTI from the same phase as yours, and compare the wiring like for like, as it seems that some of it is not right

[boombang 2]

I'd possibly go even further than above - with big wiring issues it can often be easier to strip out loom and replace.

 

I've got VCG looms in a parts 309 on my drive but you are way too far and it'll cost a fair bit to send looms up.

 

Its also 1992 spec so has the screw together plug on front of inlet manifold, although isn't catted

Edited September 25, 2006 by boombang

[mickie 3]

 

ive just worked this out and its made the fuel pump run and it hasnt popped the fuel pump fuse but i still dont know if its pulling the right amount of current, what should it be pulling though ?

 

i might have to buy that off you boombang if i cant get sorted, i dont have someone who ownes a gti near me, not that i know of, very random why they've moved the cable from the starter motor inside the car instead of to that brown multi plug, i have no idea where its supposed to connect to the multi plug so i guess i'll have to search for that

 

edit: right then

 

i dont know what a fuel pump is supposed to sound like on a 205gti but mine aint sounding too quiet..

 

just a second ago i jammed a bit of wire in the relay switch that i now know only supplies electric to the fuel pump..

 

i started the car and it worked, it idled real low which i think is due to the fuel pump not working right, its the only thing it can be cant it ? then after 30 seconds the relay board popped again, probably again due to the fuel pump pulling too much current because where it pops on the board supplies electric to the fuel pump only..

 

so i think im happy now im pretty sure its the fuel pump and my next post will hopefully be me saying it lives and it was the fuel pump

Edited September 25, 2006 by mickie

[futura 3]

Do you have a spare fuel pump handy?

[mickie 3]

no but ive ordered one, hopefully i'll get it tomorrow

[mickie 3]

im happy i said it hopefully might work because its still fu£%ed

 

just got my fuel pump today, fitted it, works and i think its a bit more quiet than my last but it still pops the relay

 

this is my old relay i have which works even though it looks a real mess.. but again, it runs for a minute then pops the board then i have to go fix the relay again & again & again..

 

i dont want to try my new relay in because i know it'll just pop like the last 3 i've had.. im really sick of this now..

 

whats my options ? someone please help

[welshpug 1,657]

either remove all the additional wiring and start from scratch or fit a new loom.

 

there must be a short or an incorrectly qwired component in there somewhere.

 

check the loom where it comes through the bulkhead.

[futura 3]

You must have some wiring problem. For the fuel pump to draw such a current that heats the relay to 230 Celcius (solder melting temperature), there must be some kind of shortcut going on, and I would expect it to come from the wiring in the first place, rather than the fuel pump itself?

In addition to what Welshpug said I would recommend you don't use your brand new pump to do your tests, it won't like such high currents that keep blowing your tachy relay

[mickie 3]

the fuel pump and relay were the easy options and a few people said it would/could be that, no more tests are going to be done with that old relay i have, the time has come for me to rip out my dash and look at everything properly..

 

first thing im going to try is disconnection the purple wire on the starter motor and putting the blue cable on which goes to the brown multi plug thats just been left off

i really dont get how this car worked when i bought it

 

cheers for the help

[Bassman 1]

the fuel pump and relay were the easy options and a few people said it would/could be that, no more tests are going to be done with that old relay i have, the time has come for me to rip out my dash and look at everything properly..

 

first thing im going to try is disconnection the purple wire on the starter motor and putting the blue cable on which goes to the brown multi plug thats just been left off

i really dont get how this car worked when i bought it

 

cheers for the help

 

Have you got a diagram of the connections to and from the tachy relay? The tracks that keep blowing on the relay circuit board, which pin are they connected to and where does this go? Could it be that it is not to the fuel-pump, but another connection?

 

Does a particular wire get hot just before the relay pops?

 

Good luck!

[mickie 3]

the cars running

[luggy 13]

Result!!!!!

What did you do to fix it? stick some pics of what you did.

[mickie 3]

ive connected the cable below together, it used to go straight to the starter motor through that purple wire with one sticking out of the block not doing anything

 

and the blue wire from the brown multi plug now is connected to the starter motor

 

and now the car runs

 

im still concerned about these wires tho

 

 

white wire = blue = 10amp fuse = yellow = block..

 

is this supposed to be like this ? i cant see why they have done this

Edited September 28, 2006 by mickie

[luggy 13]

Hi Mickie

I suppose thats one way of getting a fuse in to the circuit, Im not very experienced on the electrical side of things but the only advice I would give you, if your not already doing it is leave the battery disconnected when the vehicle is unattended until you are happy/confident that the wiring isnt going to make the vehicle spontaneoulsy combust. How longs it been? nearly 3 weeks since this thread was started, good effort on getting it running.

 

Luggy

[mickie 3]

cheers luggy, yeah i've still got my hardwired relay in so i have to disconnect the battery to stop the fuel pump running as im still not happy about that inline fuse thats not supposed to be there.. so i dont wanna put my new relay in just yet..

 

im stuck now tho, i need someone to have a look at there wires for me, see what goes where..

 

 

that white wire is 74 fuel pump live and the yellow one is 74a

 

but i dont get it, 74a isnt in my haynes wiring diagram so i dont know what that is..

 

i dont get it because that white wire thats connected to the blue one is 75 fuel pump live but on that connector block there is already a 74 fuel pump live thats never been touched apart from the yellow 74a

[mickie 3]

 

ive traced back all the wires for this and they're just what ive said, fuel pump live from the relay through the 15amp fuse then to the fuel pump..

 

ive got rid of the 10amp inline fuse now and tried the car with the 15amp fuse out (pump doesnt run) then its ok when i put the original 15amp fuse back in..

 

everything seems to be right, im just confused why the fuel pump live comes from the relay white and then connects to a yellow wire, its like something is missing

 

i need a look at someone elses board

Edited September 28, 2006 by mickie

[luggy 13]

Did the guy you bought it off give you a reason why he was selling? because I think youve just solved the problem he had which and his apparent solution was to put that 10amp fuse in. If you notice on in the Haynes manual there is a connector between the Tachy and the starter motor, that purple wire was the cause of the faulty tachy. Have you found out where the purple wire goes?and is the fuel pump still turning even with the ignition on?. If a I get a chance when I get back from work Ill take some pics of the same area on my board and attempt to load them on here!

[luggy 13]

Had a look at my fuse board and the yellow/blue wire you have.

Got continuity between between yellow/blue on the fuseboard and on the Tachy connection, the blue wire as well as (green/yellow) wire, both either side of the #20 brown live and also the cream/white #76. Hope this helps.

 

Luggy

[mickie 3]

the guy i bought it off bought a new car and that was his reason for selling it also he was a big c$%t you wouldnt want to mess with

 

yeah i noticed the connection between the techy and starter motor, thats why i thought it may have been that to fault.. but i just connected the starter motor to the brown multi plug in the engine bay..

 

the purple wire that went to the starter motor was just thrown in for some unknown reason, i've took that out

 

ive put my new techy relay in now and the car works which way it should, everything turns off when i pull the key out..

if you could take some pictures of your board that would be amazing because only gti's have the bit on the board i need to check, its the only thing left im stuck on even tho the car works fine

 

 

well apart from brakes, clutch, speedo and exhaust

not the best drive at the mo, cheers for your help

Edited September 28, 2006 by mickie