Is it fuel lift pump or fuel injection pump problem?

[sky2you]

Hi,

My 2004 Cummins ISB engine truck got 128 094 fault code.
"Fuel Delivery Pressure Data Valid but Below Normal Operating Range"
Is it fuel lift pump or fuel injection pump problem?
Please advise.

Thanks in advance,

[Rawze]

I would think if it is on when engine is running, it would be a delivery problem, but i am not familliar with ISB.

[sky2you]

(04-26-2016 )Rawze Wrote:  I would think if it is on when engine is running, it would be a delivery problem, but i am not familliar with ISB.

Thanks Rawze,
Does "delivery problem" mean that I need to check whole fuel supply system?

[Unilevers]

i believe that code pertains to the lift pump and supply circuit - not the high pressure side.

[hhow55]

My take is, like the code say's, Fuel Delivery Pressure Data Valid but Below Normal Operating Range

The pressure is below normal operating range, which make's me think it would be on the pressure side and not the suction side. Just my 2 cent's

[Hedley]

try a different fuel filter, you may be using a fuel filter that filters more microns than your engine is designed for, check with fleetguard for the correct filter for your application.

[sky2you]

It is bad fuel lift pump.
I have checked inlet fuel line of fuel filter and turn key on and see if there is any pressure, also I have touched the fuel lift pump which is located behind ECM cooling plate on ISB engine, to see if it is running when turn key on, too. Both test results are failed so it is bad fuel lift pump.

After replace the fuel lift pump, the problem is fixed, no more 128 094 fault code anymore.

Thanks for your help.