I know for sure that pin 10 on all the Cossy Weber ecu's gives an earth to the EFI relay, is this simply an earth that's there all the time provided the ecu is plugged in?

 

Some cars use it like an immobiliser feature. Where the key tells the ecu to to turn on....then part of the ecu actually activates a power relay to turn itself on. If that makes sense.

I think it's the same pin I had to earth out when I fitted an aftermarket ecu with a patch harness in order to make it power up via the key as the OE ecu was no longer plugged in.

 

Switched earth?clever.so if the thief tries to put power directly to it it should blow something internally to prevent the car being started.could also provide a safety feature for voltage spikes etc.

 

not really claver, earthing it will energise the relay.

But a lot of ecu's become a remote trigger to power the ecu and other circuits up now. I guess easier to link the immobiliser functions inside the ecu to start with.

Hence why many components on modern cars need coded to the ecu etc.

 

This any good Mart

 

 

Thanks Richie but I already have a diagram I just wondered if there were and circumstances where the ecu could remove the earth.

 

Alot of info on ECU's on this site

http://www.bigturbo.co.uk/

 

How does it prevent the fuel pump priming if there is no crank signal ? ? ?

 

Because the EFI relay controls the pump, no earth to the EFI relay means no pump working too.

 

Cheers

 

Do you have a higher res version of that diagram Richie?

 

I have them in PDF.............Whats your email ? ?

 

martin@reyland.co.uk

 

Martin,

Pin 10 is simply a safety backup interlock for the fuel injection system.

As said above, it provides an earth for the main power relay that supplys the whole system.

Remove the ecu and all the components relating to engine drive are de-energised except the ignition module and coil.

The ecu cannot switch this signal.
Some ecu's provide this earth via a diode but that doesnt affect how it works.

 

Thanks Richie