Yet Another F Ing Gti6 Non Starter

[Mattr5uk 20 5 Cars]

Finishing off the last few odds and sods on my conversion (sorting ride height and some welding below headlamps) below and behold the thing no longer starts. Had previously started on the button now I'm getting intermittent fuel pump priming with ignition on and I've lost spark and injectors are not pulsing. Checked over the converted loom no obvious issues. If I apply feed to fuel pump it prime but still no start. I suspect the Crank sensor I have checked voltages quickly, I have a good earth and the other 2 pins were reading around the 2.5v mark with ignition on. I'm hopeing the ecu hasn't locked itself but I can only see it being one or the other(ecu or cps). Any advice or suggestions would be much appreciated.

[Anthony 1,000]

Tried another injection relay? If its only intermittently priming it sounds more fundamental than a crank sensor IMO, as it should prime every time you switch ignition on.

[Mattr5uk 20 5 Cars]

Yes I had another one kicking about that I've fitted still no different, it was off a later loom but I'm sure the numbers matched. Can't remember if it did it before it failed to start but all the gauges drop off when cranking, I've tried another ignition switch to rule out and again no diffence.

Edited November 29, 2014 by Mattr5uk

[Anthony 1,000]

All the auxiliary gauges and lights dropping out is normal, although the tacho should still read.

 

All the GTi-6 relays are interchangeable, so providing the numbers matched it'll be fine even if it's off a later loom.

 

Have you verified that you've still got the correct voltages at the relay socket for constant and ignition switched supplies? Can't remember them off the top of my head without referring to my notes which I haven't got to hand, but a search will reveal what you should be seeing.

 

Given that you were welding before it failed to start, did you have the battery disconnected? I know ECU's occasionally don't take kindly to being exposed to voltages nasties that you can get from the welder if the battery is left attached.

 

That said, a faulty crank sensor or a locked ECU will both show similar symptoms to what you're seeing - fuel pump will prime but there will be no spark/injection. Only point of note as I said is that the fuel pump should prime every time - for 10 seconds or so first time after the battery is connected and 2 seconds or so subsequent times.

[dobboy 231 2 Cars]

Howdy Matt, if your sure the loom joints are good, is the inertia switch shorting good?

 

IIRC on the plug for the double relay you should get 12v at pins 11, 2, 8 and 15

 

And an ignition live at 14

 

The pin numbers are on the face of the loom plug but you need good eyes and light to see them.

 

And take it from there.

[Mattr5uk 20 5 Cars]

Cheers jack, have you wires in your odb connector yet? Think I will make time to get mine wired up May give a little more info.

The car had run after welding it up, I shall check voltages down to relay tomorrow and see what I've got.

Inertia switch is fine but ill bridge it out to rule that out.

[dobboy 231 2 Cars]

Hi Matt, no ODB yet, the wires are in and coiled up in the dash pocket. I've never found what gets soldered on the end of the wires in a scrappies.

 

If your pump primes when fed with a jumper then i think it can only be the relay or the joints where you married the loom.

 

Good luck

[Mattr5uk 20 5 Cars]

All voltages good to relay, managed to wire in plug for scanner no codes present and live data looks ok except no rpm signal on cranking so I'm hopeing it's pointing to cps. One on the way TBC.........

[dobboy 231 2 Cars]

Matt i would have posted you a CPS to try.

 

Still, how can the CPS stop pump from priming?

[Mattr5uk 20 5 Cars]

Fixed I think the fuel pump priming issue was possibly a red herring like Anthony said about the priming times from ignition first switched on. New cps fitted from Ecp £15 and started on the button. The only good thing to come from this is finally wireing on the obd socket.

Thanks all for advice

[dobboy 231 2 Cars]

Magic.