2008 WH 3.0 CRD no start

[alexbrown64]

I’m assuming it’s cranking over ok, but just not starting?
Here’s an interesting thread on a similar problem to yours.

http://www.peachparts.com/shopforum/...placement.html

Like in the thread, I would be going over all your fuel lines and checking for loose fittings. You have had it running, so must be something simple like a wire got burnt or came loose, or your loosing prime.

I don’t know which hose provides fuel to the filter. Do you have the manual?

Cheers,

[Stewatpark]

In your photo of the fuel filter the top larger diameter hose is the diesel supply line from the fuel tank .

In your other photo the bottom steel line ( not the one that goes into the steel junction box ) is the diesel supply line from the fuel tank .

[giacomo.m]

Thank you Stewatpart and alexbrown64
the engine crank ok, but not starting and i can check the crossover injection line at rail for loose fitting....

Giacomo

[Stewatpark]

When the engine is off the fuel common rail loses the fuel pressure .

When the engine is being cranked the fuel common rail fuel pressure has to reach about 3600 PSI before the engine will start .

If air is leaking into the fuel system and there is air in the common rail the common rail can not easily attain 3600 PSI under cranking because the air is being compressed .

Some good information at - www.oregonfuelinjection.com . Article - Jeep diesel diagnostics , 2007-2008 3.0 l Jeep Grand Cherokee .

You need to crank the engine with a scanner hooked up and read the fuel common rail fuel pressure under cranking to see what is going on .

[giacomo.m]

It seems to me that the fuel common rail fuel pressure is fine, while I wanted to know if the fuel rail pressure volt must increase at the time of cranking and how I can measure the voltage on the injector connector not having an oscilloscope ....

Giacomo

[Stewatpark]

That photo appears to be with the engine cranking at 182 RPM ( should be above 200 RPM ) . The actual common rail fuel pressure reading is showing 30.5 PSI . The pressure should be 3600 PSI under cranking .

It appears that the problem is that the common rail fuel pressure is not building to the required 3600 PSI .

The stipulated cranking common rail fuel pressure required to start is reading 3625.9 PSI . This is just showing what pressure is required to start the engine .

Did you change the fuel filter recently ?

Did you read that article that I referenced above ?

Warn out injectors with excessive diesel leak back can also inhibit the common rail from reaching 3600 PSI under cranking .

Is the electric fuel pump in the fuel tank pumping fuel to the fuel filter and on to the high pressure fuel pump ?

From that article - " The fuel pressure regulator in the high pressure pump and the pressure regulating valve in the rail control rail pressure " .

[giacomo.m]

But the pressure read in the rail is not 3625.9 psi Fuel Rail Press. Stpt ....?
I have not replaced the diesel filter recently, but only the oil cooler
I checked the flow of diesel fuel out of the filter purge valve and it is ok, so pump ok....
so in your opinion the cause of the low pressure in the rail could be the fuel pressure regulator in the pump and the pressure regulating valve in the rail ?
thank you

Giacomo