does anybody know what this wire does, is it an input or output from the relay?

 

its an input permanent feed if i remember right mate

 

so if it wasnt getting its input feed, would this cause the fuel pump not to run?

 

well id have to get me book out but just trying to think the black /yellow comes from the ignition and links to the ecu and then does some sensors as well there all joined / soldered together in the engine bay . so yea if its not connected it will affect the pump id imagine mate . blacks / colour are input wires where as brown / colour are earths

 

thanks for that, so if i test it, it should be an ignition live?

 

yes mate should have volts on it with ignition on and while your there make sure you have volts on pin 30 the red wire with ignition on

 

right, ive just tested the wires with ignition on
pin 15 black and black/green wire = live
pin 30 red = live
black/yellow = nothing.

does this mean my problem may lie at the black/yellow wire???

 

right ive got the S1 book out .......
yes black and black green which are on the same terminal go to coil and injection module should be live with ignition on . looking at this now the black / yellow is only powered up when the engine is cranking over on the starter so its only live briefly . . you say your car runs for a few seconds have you messed with that yellow relay behind the heater at all ??

 

i havent messed with it BUT instead of there being a permenant live and an ignition live, there is 2 ignition live wires going to it (whicj i guess the previous owner did), could this be linked?

 

dunno be strange if they have as long as the red is on when the ignition is should be ok though in the book it shows the red coming straight from the battery through a fuse wire link and fuse in fuse box (live permanently )

 

yeah i notcied that it should be connected straight to positive so i'll think i'll change that to what it should be anyway, still though that shouldnt really cause the fuel pump not to run then should it.
so if i test the black/yellow wire when cranking, there should be power on that wire?

 

no it shouldnt affect the pump running but other things control the relay if the car doesnt start and its up to pressure the pump wont run anyway . its hard to diagnose if your not there i dont know the history of the car but there great easy engines and it will be a simple fault when you find it . its easy to say this and that but id be looking for bad connections , that yellow relay behind the heater , injectors stuck open or clagged up etc

 

thanks for the advice, the suggestions of what the problem could be really do help. i have the whole day off tomorrow so guess i'll have to spend the day trying to figure the problem out. is there anyway to test if the relay isnt working (could i by-pass it at all) any ideas to help rule individual things out would help.
the car starts and runs for a few seconds then just cuts out???