Ignition live

[Colonel Sanders]

I have a problem,
My car died, i checked pin 27 on the motronic connector, and its not live.
So i checked if the DME relay was clicking when the ignition was switched on, and it didnt, so changed it round with a couple of spare DME relays i have lying round and still nothing!

Its an M20B25 with megasquirt plug and play, so none of the loom was butchered, so im really stuck now, and the car is really getting on my tits as its finished now!!!!

Maybe the great Mr Mooooore can shed some light?
Cheers

[FlappySocks]

The DME is not going to operate without the ECU connected (Megasquirt or Motronic).

Anyone know what fuse supplies the ECU?

[FlappySocks]

Just a thought... does the OBC immobilizer cut power to the ecu?

[Colonel Sanders]

OBC still works mate, il plug the ECU in and try the DME again.

[Brianmoooore]

DME relay isn't switched directly by the ignition live. Ignition live (green wire) goes to a part of the ECU that is always powered up. and then the ECU switches the DME relay, powering up the rest of the ECU and the injectors.

[Colonel Sanders]

Would a faulty crank sensor cause this problem?

[FlappySocks]

No. If your not getting power to the motronic plug then it's got to be a fault somwhere between that, and the ignition switch. An immobilizer may cut the ecu power.

[Colonel Sanders]

I took all of the immobiliser out today and connected wires where they were ment to be, but still nothing, no power to pin 27, no spark, and no fuel pump.
Really starting to bug me now. anyone else have any thoughts?

[Brianmoooore]

Do you get ignition switched power to the green wire on the ECU, and are the (red) permanent live and (brown/orange) earth connections to the ECU OK.

[Colonel Sanders]

i tryd the green wire, that come from the ignition, that went live when switched on, and i have triple checked the connections to the ecu.
the only other thing i can think of is all my spare DME relays are duds??
is there anyway i can jump the DME to find out?

[Brianmoooore]

DME relay is easily bypassed. Link together pins 30, 87 and 87a or b.

[Colonel Sanders]

could that be the problem then? just cant see all my relays being shot!

[FlappySocks]

I dont think the DMA has anything to do with it. DMA is switched by the ECU. ECU not getting power.

[Colonel Sanders]

then i dont know, what it can be then? as the whole immobiliser has been trced back and removed, and all wires were reconnected properly. but still no power, been through the whole loom checking it, still nothing. power everywhere else.

[Colonel Sanders]

just had another good search on the forum, and just realised, i have power from the green wire, where it comes out the barrel when ignition is switched on. but its not live when it reaches pin 27, so the fault must be along there somewhere.
any common causes for this? and where to look?

[Brianmoooore]

just had another good search on the forum, and just realised, i have power from the green wire, where it comes out the barrel when ignition is switched on. but its not live when it reaches pin 27, so the fault must be along there somewhere.
any common causes for this? and where to look?

Very common cause for this: Immobiliser! Don't assume you just have one - I've found up to three of varying ages in E30s; all connected and all defunct.
Look for a two pin socket with identical green wires going to both pins, above the middle of the glovebox, and check for power here.
There is also a plug and socket where the ignition switch plugs in, which should be clipped to the steering column, about half way down. Check that the two parts are pushed together properly.

[Colonel Sanders]

the immobiliser i found, i removed fully, i stripped the glovebox, and steering coloum, but il check for more tomorrow. just seems wierd the way it cut out all of a sudden??

[Colonel Sanders]

No end of problems on this car!
Found the problem, the two pin connector above the glovebox with the two green wires, disconnected it, and looped the two plain green wires, and it started straight away, lovely i thought.
Then smoke from my brand new MSD coils, and it cut out, i now have 3 expensive burnt out coils!!!
More money down the drain!!!!

[Colonel Sanders]

anyone know if this could have caused my burnt coil problems? it was only coil 3 that was burnt, should have my new one soon, but i dont wanna burn another one out.
could a simple short on the wires going to the coils have caused it to burn?

[FlappySocks]

Doubt the coil has anything to do with the iffy ignition connection. Separate problem. Anyway, dont use the new coil, until you understand the problem. Use an old one.

[Brianmoooore]

The fact that there were wires plugged into the connector with the green wires, instead of the loop as standard, shows that there was another immobiliser in circuit.
The coil problem is nothing to do with this. The only thing that would burn a coil out is if the coil driver in your ECU became switched on for a considerable time, or the wire between the driver and coil shorted to earth.

[Colonel Sanders]

i did noticed the coil was still making noise and burning as the ignition was on but the car wasnt running?

[Brianmoooore]

I know nothing about MS specifically, but on all ignition systems since the old contact breaker points, there should be no current through the coil without crank sensor pulses.

[Colonel Sanders]

Ok, it just made me think about if that green wire loop i did might have caused something.
As the car was running really well before that. Hope it was smething simple like on of the coil supply wires earthing to the body or something?