Auxilary output question

[mark Chapman1436215423]

Hi I thought I had connected up Aux 6 as a fuel pump output (The other fuel pump is on aux 4 and works - it is wired through a loom adapter that I bought - the extra fuel pump i wired myself) It is my understanding that the aux output provides a ground when it is activated. To this end, I connected the aux output to the -ve terminal on my secondary fuel pump solenoid. When I then stored and turned the ignition on, the fuel pump relay did not energise. I tested for continuity between the aux6 terminal and earth on the car body - again there was no continuity after the ignition was turned on (Or indeed at all) Am I wiring up incorrectly ? Thanks

[ashesman]

Auxiliary outputs always switch to ground.  Relay coils wired to auxiliary outputs must be fed from an ignition switched supply, not hot fed from the battery.  the large switching contacts in the relay can be hot fed from the battery.

The problem here is that you are trying to run two Fuel Pump auxiliary outputs.  Unfortunately no warning appears, but there are some auxiliary outputs that can not exist twice (fuel pump, tacho, boost solenoid and some others).  The last auxiliary output selected as Fuel Pump will be the one used for fuel pump.

Here is what to do:  Wire your extra fuel pumps relay to the same auxiliary output as the original fuel pump.  That way the ECU will turn both fuel pumps on together and only one auxiliary output needs to be selected as fuel pump.  The only other option is to setup your new fuel pump as a GP output that turns on when RPM is greater than 100.  That way the extra pump will run during cranking and engine running, but will not do a key on prime.

I will add some notes in the help file about selecting Fuel Pump on more than one aux output.  We have added provision in PCLink to provide warnings for this in the future.

[mark Chapman1436215423]

Thanks for clearing that up for me! I'll go for the second suggestion, i'll get that set up tomorrow. Many thanks