No the wiring is all in conduit or wrapped in loom tape

Thanks dave I thought that would have been the case. Just one of the messier parts of my build at the moment as there so many wires that all meet up at the fusebox coming & going in all sorts of directions!

Anyhow I had a good look last night I definately don't have anything that looks like the relay you posted. The only relay that had it's own fuse on the side in my donor was part of the ecu which I removed ages ago before getting it running the 1st time. Any idea what else I should be looking for as I'm guessing the relay was changed in the later cvh sierra's which had fuel injection like mine?

Looking at the wiring diagrams I cannot see any integration between the original cfi system and the rad fan. Have you had the fan working at all?

Even if the fan was not connected it should have no effect on the engine running as the fan had its own seperate power supply.

Nope I've still yet to connect up the fan and cooling system really. I've had a look at the wiring diagram and as far as I can see the yellow black wire from the barrel goes to:

inst cluster (via fuse 22 - connected & earthed)
anti-theft module (removed)
fan relay (not connected)
power delay relay 5 (removed)
eec4 (removed)
edis (connected & earthed)

I also had a closer look at the fan relay in the wiring diagram and it's wires go:

barrel - black wire changing to yellow/black after a solder joint
fan switch - black wire
battery + (via fuse 33) - red wire
battery - brown wire


so I'm still a bit lost as to why I get continuity on the yellow/black wire at the barrel when the key is in position 0 or 1, but as soon as it goes to position 2+ it doesn't? Like you I can't understand why the fan not being connected would interfere but it's the only thing on the yellow/black route that isn't connected. I've checked all the earth wires for continuity (between the start of the wire and the battery - ) and they all checkout fine. the only other thing I can check I guess is if any of these fuses have gone?

Try this.

With the key in position 0 and the battery connected. Connect the negative of the multimeter to an earth directly on the chassis, and touch the positive of the multimeter to the red wire on the back of the barrel.

You should get 12v.

Touch on yellow wire & turn key to position 1. Should get 12v.

Touch on black/yellow wire and turn to positon 2. Should get 12v.

If you havn't got 12v, touch the meter on the yellow then red wire and check you have still got 12v. If you have I would say the switch is knackered. If you loose all 12v I would have thought a dead short or similar.

To check if it is the switch just use a short piece of wire and short across the terminals on the back of the switch. If you go red to black/yellow dash should light. If you go red to black/blue engine should crank. Connect red to black/yellow & black/blue and it should run.

I'll try this tonight to check the readings again on an earth point instead of directly against the battery - .

I would hope the switch isn't knackered as it's just been sitting there since I last used it a few months ago when I know it was working!

Is there supposed to be an earth of some kind for the barrel itself as from memory I only remember earth wires for the stalks?

No earth wire at the ignition barrel.

Well I couldn't find the multimeter so I've got to do some more digging around in the mess that is my garage.. I did try holding a bit of wire between the red and yelow/black & blue/black solder joints on the barrel and nothing happened :(

Like TT said earlier in this thread I must be missing an earth somewhere. So here's what I've got, does it anything jump out as missing?

1) battery - to battery tray (chassis)
2) big black wire from the starter bolted onto the gearbox
3) earthstrap going from the back of the head to the battery tray
4) fusebox common earths onto the tunnel
5) edis,megajolt,tps,coil,etc earth onto the on the tunnel
6) instrument cluster earthed onto the tunnel
7) steering column stalks earthed onto the tunnel
8) fuel pump earthed onto the tunnel

I assume in number 2 you mean a black wire from the bellhousing bolt directly to the negative of the battery.

Also are you still using the Sierra fusebox, as I don't recall there being any earth wires directly out of the fusebox.

Out of interest have you tried shorting from the main battery feed on the starter motor to the small impulse connector on the starter to see if it turns over?

Been re-reading some of your posts. Is the battery new / fully charged / in good condition? Your initial test with a multimeter could show 12v because it is using hardly any current. As soon as you apply a load to the battery if it is dead it could show 0v.

Shorting the starter as above would show if the battery is good or bad.

Ya I'm pretty sure the thick black from the bellhousing goes up to the battery negative, think its just bundled in with the thick red for the starter from memory (which is poor lol).

Yup I'm still using the orginal sierra fusebox with all of the redudante relays removed. Theres definately some common earths coming out of it. If you look at the wiring diagrams in the service manual, it shows one in cell G3 on diagram 1 for models after 1990 for example.

No I've not tried shorting the starter and up till now I've assumed the battery is still good as it's fairly new but obviously has been sitting since xmas when I last ran the engine. I'll have to check the charge on it tonight to see if that's the problem.