2G fuel pump will not turn on

[leecastillo]

Im having problems getting my fuel pump to turn on. To make a long story short, I have a 98 eagle talon tsi awd that has been sitting for the past year and a half while being built. I originally had a black box ecu (shown in pic 1). I did not want to to go with the tuning that they offered so i called Tom over at ECM link and he got a me a 2g ecu modded for a97-99/W v3 full.Now I am not discrediting ecm link or Tom nor am I blaming them for my issue.

Here is my issue, the fuel pump
(255hp) will not work while plugged into the car. My first step was to check voltage at the wiring harness at the fuel pump hanger with the key in the on position and while using link to activate the fuel pump. I also checked the voltage with link off at the fuel pump and both times it was 9.$$volts(shown in pic 1).

My next step was to pull the fuel pump hanger out and inspect the wiring, all the the power and ground wires had continuity to the power and ground pin shown in pic 2. Next I pulled the fuel pump out and used alligator clips to connect them to the top of the fuel pump to a battery and the fuel pump turned on. I then reconnected the fuelpump back in the hanger and did the same at the connector shown in pic 2 and again the fuel pump turned on. Knowing this, I reconnected the hanger back in the car and it once again still would not turn on. So i then traced down the MPI/MFI relay and replaced it
and still the fuel pump would not turn on.

Next i started looking at the ecu making sure every thing was plugged in tightly.
I looked at a pin out diagram of the ecu and found the fuel pump wire (pin 8 red and white color wire) shown in pic 3

and the wire for the MFI relay control (pin 38 light green color wire ) shown in pic 4. Both of these wires, with
the key in the on position, shown 11.$$ volts. At this point, I do not know what else to check.

I would like to jump the fuel pump relay or check continuity between the wires, but I do not know how. If you have any insight on my issue or a possible solution, feel free to comment below. All help is greatly appreciated and thanks for your time.

 

[Spyderman7]

That sucks.I would of done everything you did and for it to still not work is confusing.

I would just wire it to a toggle switch with 12v trigger or relay and call it a day.Unless someone else knows what is going on??

 

[wrencher]

The injector/coil power section of the MPI relay is controled by that Blu/Grn wire in terminal 38 of the ECU connector. ( the MPI relay is a dual relay, one for inj/coil power other for fuel pump)
The ECU grounds the relay's field coil to activate the "contacts" in the relay to power the componets wired to it.
If you see voltage near battery voltage there on the ECU relay control wires for the MPI relay, the relay is not activated.
You are geting the supplied voltage to the power side of the coil thru to the ground side of the circuit to the ECU. Otherwise an inactivated circuit = open -volts will be high.
Activated/relay on -the voltage will be low- like .2-.3 volts or less.

According to my wiring diagram, the fuel pump control portion of the MPI relay is controlled by a white/red wire on terminal 8 of the ECU.

The black / blue wire is the powered output from the relay to the pump.
The ground is a constant hard wired ground to the hangar's connector check it also.(black wire)

if you where to disconnect the ECU connectors & ground that white/red wire (ensure it's the correct one) with the key on the pump should run if the circuit is sound.
That would confirm the ECU is not commanding the relay on.

There is also a fuel pump check connector. This is located on the center of the firewall.
It is wired into the output from the relay to the pump. It is also a black/blue wire.
Supply it with power the pump should run.

 

[leecastillo]

hey guys thanks for all the helpful info I ended up going all back though the whole fuel eletrical system and i think the MPI relay was not pluged in all the way so all is in working order fuel pump kicks on whitout a issue

again thanks for the help Lee