C900 LH2.2 ECU Pin Out Question.
I'm upgrading from 8v to 16V and everything's gone fine until I tried to check out the fuel pump relay operation in advance of firing her up this weekend coming.
I've decided to use the 2 relay's that came with the 16v injector loom and ECU rather than use the existing 8V fuel pump relay...plan is to leave in situ but cut the Grey/Red fuel pump feed after the 8V relay output, cabin side of the bulk head connector (upper white one - think it's connector 152?), and run the T16 fuel pump relay pin 87B 12V output back to the fuel pumps in place of the 8v relay feed.
Here's the snag.....everything's working fine bar the fuel pump realy getting an earth from pin 17 of the ECU...I checked the relay (and it's operation and resistances, and open and closed operation etc when feeding the actuator connections with 12V across it....nice click and works fine....managed to try it in another T16s....relays are fine.
The fuel pump relay actuation voltage is getting a good 12v from the main relay alongside it via the overboost fuel cut of switch .....at this point ignition is on (fed off a green/white tap off in the fuse box) and the main relay is being activiated via the ECU...just not getting a ground for the fuel pump relay - Purple wire is good from relay to 25 way plug at ECU ........( so can't get the 12v feed to pin 30 across the relay to 87B and thence to the pumps.)
That's the prelude to the Question.......
What conditions need to be met to trigger the ECU to ground out pin 17 or can I just ground the pin 17 and be done with it............rather not go that way as it seems pin 17 on the ECU is there for a reason and just using the 8V fuel pump relay in the fuse box seems wrong...sure Saab put those 2 relays in there for a reason when they went ECU injection.
Any guidance greatfully recieved,
SteveI