F200XTR HP Fuel Pump not activating

[boscoe99]

..........

[Andrew1970]

Yes understand the pump locations
just checked grounding now

At key switch ON the following occurs

LP Pump R/Y + L/W is grounded
HP Pump R/Y + L is not grounded

[boscoe99]

...........

[Andrew1970]

Sorry will clarify

LP Pump unplugged from harness
Harness plug R/Y + L/W = 12.5 volts
R/Y to ground on block = 12.5 volts
L/W to ground on block = few mV

HP Pump unplugged from harness
Harness plus R/Y + L = few mV
R/Y to ground on block = 12.5 V
L to ground on block = few mV

Further tests
On the main harness plug that connects to the Pump Driver/modules. With Driver disconnect from harness
R/Y to ground = 12.5 V
L to ground = 12.5 V
L/W to ground = 12.5 V

Do the last two readings make sense I thought these were connections to the ECU that con*****ed negative side circuit and yet when put to ground show a voltage. Am I missing something here ?

cheers

[Andrew1970]

Is the following assumption correct based on voltages going into and out of Pump Driver

LP Pump ECU has voltage to ground in (L/W wire )and no voltage to ground out hence LP pump is running continually at key ON

Does this indicate the Driver is faulty?

[Andrew1970]

Hello

Can I please have the experts check my logic on faulty finding the Driver Module

Expected conditions normal operation:
Key ON
- LP Pump not active (only active 10/20 second cycles during running below 1500 rpm, continually running above 1500 RPM, source service manual)
- HP Pump active for 5 seconds

Wire R/Y is 12V active wire
Wiring diagram contained above in Boscoe post

Testing:

At key ON

LP Pump
ECU Pin 16 - Control wire colour B/W
Test 1
Driver disconnected from Harness
Voltage across Harness Pins B/W & R/Y = 0 volts EXPECTED
Test 2
Driver connected to harness
At LP pump plug voltage across L/W & R/Y = 12.5 volts INCORRECT should be 0 volts

HP Pump
ECU Pin 17- Control wire colour L/R
Test 1
Driver disconnected from Harness
Voltage across Harness pins L/R & R/Y = 12.5 volts for 5 seconds EXPECTED
Test 2
Driver connected to harness
At HP pump plug voltage across pins L & R/Y = 12.5 volts for 0.5 seconds INCORRECT should be 5 seconds

Can I please have opinion that Driver Module is faulty confirmed ?

thanks

[boscoe99]

If the inputs to the driver are confirmed to be correct, and the outputs from the driver are confirmed to be incorrect, it would not be unreasonable to presume that the driver has failed.

Too bad that the service manual is so deficient in providing adequate test procedures. Typical crap Yam data.

[Andrew1970]

To complete the feedback loop a new Fuel Driver Module was installed and pumps etc all working correctly now. Thanks for the help in getting to the right answer with this one.

One further question there is a slight dripping of fuel coming from the Vapour Canister outlet when idling. Does this indicate the Canistar needs replacing

Andrew

[rodbolt17]

means the VST needle is leaking or the float is set way to low.
either way the charcoal canister is now done.
they don't tolerate liquid fuel well.

[Andrew1970]

thanks Rodbolt
Is there any performance issues or damage that can occur if motor is run until canister and possible leak is fixed

[rodbolt17]

other than an explosion of fuel vapors under the hood???
not much I guess.