Fuel pump issue

[Greywolf]

Since I dragged the beast home - I have never yet heard a fuel pump turn on.

SO: Question #1



I have a Haynes manual with a picture in it so blurry it might as well have been left out...

I also need to run down what is drawing twelve volts from the battery with everything off
(I took the radio out, so that's not it)

[shadetree]

Depending on how the swap was wired in , that connection may no longer work .

[Greywolf]

Great...

I was just looking in the Capri EVTM, and the wiring looks the same MOSTLY as what is shown for the '91 Festiva.
I'm thinking to verify the FP relay, airflow sensor (the part of it that cuts off fuel pump voltage), and take readings at the tank to see if:
1) Voltage gets there.
2) There is a path to ground

After thinking it over, the only big difference is how the Inertial Switch is wired - either before or after the fuel pump.

The Capri version is that switched 12V in run or start goes through a 15A "ENGINE" fuse, then to the FP Relay. The Ground to energise the FP Relay is applied by the FP Switch in the "Volume Air Flow Meter" (MAFS, or AIR BOX!) and this is the part that the Fuel Pump test jumper shorts around. There is also a signal from the PCM, that goes off to the starter motor - so that must be for start up, and the same for Festiva.

From the output of the fuel pump relay, 12V goes to the Inertial Switch at the left rear of the car, and from there it arrives at the In Tank Pump.

NOW- the diagram shown in my Festy manual ('89 through '93, and the car is a '91) shows switched (IGN KEY) 12V going to the FP Relay. It has TWO relay windings, and one is supplied with 12V directly by the PCM (which has been swapped out in this car for a "Rocketchips" unit programmed for a B6T). The OTHER relay winding is grounded to an input to the PCM (original one) BY WAY OF the VAFM (MAFS) and also shows the test jumper and a ground to bypass it.
*MAFS = Mass Air Flow Sensor, it's what I'm used to calling them

I guess the only difference here is that the output of the FP Relay is shown going directly to the Fuel Pump, and the GROUND from the Fuel Pump is sent on to pass through the Inertial switch - which is likely how it is still wired.

The funky part of all this is going to be figuring out how the two different sequences of handling the signal were cobbled together by Frederick before he passed on.

~ and obviously it's too late to ask him about it.

I really need to get the PCM mounted someplace in the car, it's just laying on the floor on the passenger side.

[FestYboy]

Best bet is to work backwards. Start at the pump

[Greywolf]

To windy and cold out to do anything today - I think I have the flu or something anyway.

I can do a continuity check to see if the connector goes back to the right pins on the PCM I guess.
(I found the connector pinout in the EVTM yesterday and have been looking at it)

I'm really not happy with the way it looks hacked and slammed in - (the PCM) and I'll have to do something about it.

It might be the smartest thing I can do, re-check everything and see if the engine harness is going back to where it should at the PCM, get the PCM itself mounted in a safe spot, and then run down the chassis wires.

Out of all this research I think I see a simpler way to present what's what with the harness's.

The Capri PCM has a total of 38 actual connections (wires) in three connectors, 28 of them go to the engine bay and connect to the engine & systems or are test points - so those don't need to be fiddled with. (Except that the test points, MALF Indicator Lamp, and fuel pump jumper may be not hooked up - Hmm...)

That leaves ten chassis connections and the (noted) above

Yeah - I'm going to spend some time on this to make it right, I think I want my test connections and the fuel jumper inside instead of out in the engine bay.

I need to ripout an old A/C line anyway since the condenser was hacked out to make room for the intercooler. I suppose the evaporator can go too. Maybe that will open a space behind the glove box for the PCM