How to Test Low Pressure Fuel Pump?

[jlglr4]

Wondering if anyone here knows how to test the low pressure fuel pump, or how to measure pressure on the low pressure side of the fuel system. Does anyone know if there is a pressure test port somewhere on the low pressure fuel lines?

The GAP tool has readouts for the fuel rail sensors, but that only gives the pressure on the high pressure side of the system. There also is a field in live values for the “desired” value of the low pressure pump, but this does not give any info on what’s actually being supplied. The folks at GAP have confirmed this - said that Land Rover doesn’t provide any values they can access for this parameter. They pointed me to this procedure for the LR3: https://disco3.co.uk/forum/robbies-guide-low-pressure-fuel-system-130062.html?highlight=fuel+pump, which is a great write-up, but I don’t see a corresponding Schrader valve on my 2016 SCV6 engine.

 

[gsxr]

Resurrecting this old thread. I have the same questions:

Does a test port exist for the low pressure side? I don't want to go on a snipe hunt.

GAP IID only shows fuel rail (high pressure) data. Seems like a pretty big miss, since there is a low pressure sensor that transmits a low-pressure data value to the ECU - why can't the ECU share this value?

Also curious if the dealer diagnostic tool (SDD) is able to display live data from the OBD-2 port, and it's just a limitation of GAP-IID. Not that I want to spend $500-$700 for SDD, but I would like to know what SDD can do, that GAP cannot.

 

[scapistron]

Poke around in the "service/test" menu you should find a fuel priming function.

Run the truck until it dies. If it won't restart run the fuel priming function and try again. You should be able to hear the pump prime.

 

[gsxr]

Update... there is no test port on the LR4 with V8 engine (probably not the SCV6 either). No way to attach a gauge without getting really creative and inserting a custom-fabricated "T" into the quick-connect fitting ahead of the fuel tank. Also doesn't sound like SDD can read the sensor, so that's a bust as well.

@scapistron - thanks for the tip about the fuel prime function in the service/test menu! I was not aware of this. It was helpful after replacing my fuel pump (details in this thread). Note that the pump is NOT quiet, and if you don't clearly hear the pump engage and run for about 30 seconds while this function is enabled, something may be wrong with your pump. Don't ask how I know.