3B no start help

**andy10v** · 30 August 2014, 20:17

There is no voltage at the injector fuse (ignition on, or cranking)

**andy10v** · 30 August 2014, 20:18

IM manifold earths are present and tight.

**andy10v** · 30 August 2014, 20:19

S28 injector fuse is fed from the fuel pump relay, is it possible the relay is partially dead?

**twoqu** · 30 August 2014, 20:20

Originally posted by andy10v

There is no voltage at the injector fuse (ignition on, or cranking)

Well thats the problem!
It is either the fuse or the Fuel pump relay I guess as one feeds the other!

**andy10v** · 30 August 2014, 20:26

Originally posted by twoqu

Well thats the problem!
It is either the fuse or the Fuel pump relay I guess as one feeds the other!

Fitted spare relay, fitted spare fuse, still no start.

**newsh** · 30 August 2014, 20:32

Fuel pump relay has 2 sets of contacts, one set powers the fuel pump via fuse 13 and lambda via S25. The other set of contacts powers the injectors via fuse S28 and the N71/75/80 via fuse 24

**twoqu** · 30 August 2014, 20:38

As John as said, the contact for the injectors should be closed as the injectors and the Maf should be powered with ignition on and during cranking. If not that leaves the ecu signal to the fuel pump relay.

**newsh** · 30 August 2014, 20:40

Can you check for power at S24?

**andy10v** · 30 August 2014, 20:42

Just separated the electronic ground and power ground under the intake manifold as apparently malfunctions can occur.

I am assuming fuel pump fuse is getting power as I have fuel pressure.

**andy10v** · 30 August 2014, 20:43

Originally posted by newsh

Can you check for power at S24?

Will do, the n75 clicks when doing an output test so I assume it has power.

**newsh** · 30 August 2014, 20:45

If you've got the fuel pump running but no injectors then it looks like you've lost the wire from pin 87a on the fuel pump relay to one or both of the 2 fuses S28 and S24

**twoqu** · 30 August 2014, 20:46

Thats why its a bit odd as its the same signal out of the ecu!
If you can tell which contacts are which you may me able to close the appropriate set to temporarily prove its the issue or not. You will need to pry the cover of one of the relays.

**newsh** · 30 August 2014, 20:47

Hm, just the connection from Fuel pump relay to fuse S28 missing then, if the fuel pump is running when cranking, which I guess it is as you have fuel pressure!

**andy10v** · 30 August 2014, 20:47

n75, isv and carbon canister all click on output, so must be as you say.

Really weird, I have not been in the fuse box, or under!

**andy10v** · 30 August 2014, 20:49

Can I stick +12v into the fuse slot from somewhere to confirm that will work before I dig in from below?

3B no start help

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