Fuel Pump wiring in a 2005 sti using a moristech pdm30 and a Link ECU

Hey guys,

So I'm in the process of rebuilding an entire body and engine harness for my 2005 sti rally car. The engine wiring I have pretty dialed in thanks to the club and pro wiring courses. What I'm a little foggy on is the fuel pump and how I should properly wire it to the PDM/ECU setup.

I plan on separating the fuel pump from the rear harness. I understand I need a 12v and ground connected to the fuel pump (12v coming from the PDM). As far as sensor wires and anything else, what would I need. Also, can I simply run the sensor/signal wires from the PDM and have the ECU trigger everything through a CAN Bus to the PDM? Will the fuel level sensor need to be run to the ecu? or can it run to the PDM?

I'm new to all of this so any help and proper explanation would be greatly appreciated.

-Kenny

Hi Kenny, I'm unfortunately not familiar with the specific PDM you're running but within reason they are all pretty similar. The fuel pump will need to be provided a switch 12V from the PDM and normally I use a good chassis ground near the actual pump for the earth. The fuel level sender is not really anything to do with the ECU and this only operates the level gauge on the dash. Depending how serious you're getting I'd be inclined to leave this part of the factory harness as is. In stock form the STi has a fuel pump speed controller which you'll be bypassing too so this cleans things up a little bit.

What is possible regarding CAN switching is going to depend on the capabilities of your PDM. Fortunately the Link has a very configurable CAN bus so there's no problems setting up messages for the fuel pump, fans etc and sending the to the PDM but you'll just need to check what the capabilities of the PDM are. Most will allow CAN switching so as long as the unit offers that feature you just need to configure the messages from the Link to suit the format and address structure the PDM is looking for.