Why do the Cosworth ignition module (BKL3B) have 2 wires to the ECU to pin 24 & 25 ??

I'm busy with wiring a stand alone ECU, but can't figure out why there are 2 wires from ECU to the ignition module, because normally theres only one trigger wiring from ECU to ignition module.

Who can tell me , why this is, and what the difference is between these two wires which go to pin 24 & 25 from ECU?


Regards,

Bas

 

this any good to you ?

http://www.motec.com.au/drawings/m11.pdf

 

pin 24 ign. ground
pin 25 ing. trigger
Don't know why it have it's own ground???

 

@ Jon

Thanks, but that's another ignition module as the std Cosworth one.
I'm going to use the std module, and that one is having 2 wires connected to the ECU. Or am i missing something in that diegram you were giving?


@ White 4x4 cos

Already found this indeed:

Webber/Marelli’s IAW045 and IAW048 ECU connector wiring
1 - Ground
2 - O2 sensor (IAW048 cat model)
3 - Crankshaft RPM sensor (-)
4 - Crankshaft RPM sensor (+)
5 - Camshaft Phase sensor (-)
6 - Knock sensor (IAW048) (-)
7 - Cannister (IAW048)
8 - Diagnostic
9 - n.c.
10 - Main relay (-)
11 - Gnd ref. sensors (-)
12 - ECU warning light (-)
13 - Service Connector (-)
14 - Service Connector (-)
15 - MAP sensor signal (0-5v)
16 - Wastegate control solenoid (-)
17 - Throttle position sensor (0-5v)
18 - Injector 4 (-)
19 - Engine ground
20 - 12V (main relay)
21 - Air conditioner signal
22 - Knock sensor (IAW048) (+)
23 - Camshaft Phase sensor (+)
24 - Ignition module (amplifier) out (-)
25 - Ignition module (amplifier) out (+)
26 - n.c.
27 - Diagnostic
28 - Fuel pump relay (-)
29 - Water temperature sensor (0-5v)
30 - 5v sensors (+)
31 - Intake air temperature sensor (0-5v)
32 - Injector 2 (-)
33 - Injector 3 (-)
34 - Idle valve solenoid (-)
35 - Injector 1 (-)



But this still doesn't make sense to me, because the module have it's own ground ( first to mae cooler and from there to engine ground), so why does it have 2 wires to the ecu???
And i assume i need them both to make it work with a stand alone system isn't it?

Somebody?


Regards,

Bas

 

Up

 

Ok, it has its own ground because the cossie normal ecu ground can vary
due to injector peak currents and wiring voltage drops in these conditions.
If there wasnt a seperate ground, the coil would missfire as the ground
of the ecu moves around 0.5volts during various conditions due to the trigger
signal being only a 5 volt (TTL) signal as is very suseptible to electrical
noise and disturbance.

Hope that explains things.


Simon

 

So, the wire to the ECU (pin 24) is nothing more then an extra ground but via the ECU?

What to do with that wire if you are going to use a stand alone system, so remove the std ecu? Just connect to engine ground at the car?

Thanks!

Regards,

Bas

 

That ground may or may not be needed depending on the ecu used.

 

Ok, will sort that out!


Thank you mate

Regards,

Bas