intermittent P0300 on my 2005 CRD

[seafish]

Was riding Giddyup home from work the other day and 3 miles from home she started to limp and stutter unless I kept RPMs very high and even then she was running rough. At idle she would almost die. But no CEL lit on the board.

I immediately though no power might be a boost leak, so I checked all hoses from intercooler to EGR valve and found with no leaks EXCEPT for a tiny one at or near the EGR valve.

Then I checked codes and got a pending P0300 for multiple misfires.
But I have NO idea how a P0300 for multiple misfires pertains to a diesel.

Please explain if you can…TIA

 

[seafish]

This morning I cleared the code and on a 5 mile test drive and she ran fine again.

Ideas??

 

[KJowner]

Air in the fuel system I'd guess.

 

[seafish]

Air in the fuel system I'd guess.

Source of air would be an unknown leak somewhere?? Or?

 

[seafish]

Time for the in Dodge Ram in tank pump upgrade?

 

[seafish]

@KJowner

This is what my Brave AI says…sounds about like what you said just with more details

"P0300 Liberty CRD Fuel Issue"​

The P0300 code in a 2005 Jeep Liberty CRD can be caused by air in the fuel system, which can lead to misfires and other engine performance issues.234 Symptoms of air in the fuel include rough idling, stalling, and a loss of power, especially when going uphill or under load.234
To address the issue of air in the fuel, you can check for leaks in the fuel system, particularly around the fuel filter head, as it is a common area for leaks in the Liberty CRD.234 Additionally, inspect the connections between the fuel lines and ensure they are properly sealed to prevent air from entering.234
If air is found in the fuel system, you can try bleeding the system using the hand pump and bleed screw on the fuel head to remove any air.234 If the problem persists, it might be necessary to replace the fuel filter head with a metal one, as the original plastic head can develop leaks.234"

 

[KJowner]

You could try poly tubing temporary plumbed in as fuel line, it's translucent so you can see bubbles, handy for locating leaks, you don't want to drop the fuel tank if you don't have to!

Like your link says the common leak seems to be the fuel filter, I've got the earlier Racor on mine so a bit less hassle, I see the Chinese have now copied them and are selling them on Amazon etc for less than 1/4 the price of a real one, might be worth a try, just remember you need one with the hand pump!

 

[WWDiesel]

Most likely you have air in fuel problems. If you have a leak on the OEM vacuum fuel system anywhere, it will suck air in, not leak fuel out. When this happens, it starves the CP3 injection pump for fuel preventing it from building the correct fuel rail pressure which greatly reduces engine power and, in some cases, will stop the engine from running totally.

Installing an intank fuel lift pump solves all air in fuel problems.

Most owners install the intank lift pump that was used in the early 2000's Dodge Cummins trucks. It is a direct drop in the tank replacement for the OEM fuel and fuel gauge module. All you have to do is add two additional wires to the harness from under the rear seat area to the top of the fuel tank. The vehicle is prewired for the lift pump, with a relay, and the correct logic in the ECM for the lift pump. The wires are already run all the way to under the rear seat to a connector, so you only have to add two wires. See this:> http://www.auerbach.ca/kj/lift_pump/default.html

The OEM fuel line fittings that connect between the fuel tank and the metal fuel lines on the frame are push on gasser type fittings and are not designed nor do they work well for vacuum fuel systems, they are designed for pressure fuel systems. So when used in a vacuum fuel system, they can and will allow air to be sucked into the fuel system.

Some owners have removed both of the push on fittings, one at the tank end, and one at the metal pipe end where it attaches to the frame.

 

[seafish]

Most owners install the intank lift pump that was used in the early 2000's Dodge Cummins trucks. It is a direct drop in the tank replacement for the OEM fuel and fuel gauge module. All you have to do is add two additional wires to the harness from under the rear seat area to the top of the fuel tank. The vehicle is prewired for the lift pump, with a relay, and the correct logic in the ECM for the lift pump.

Yesterday I ordered the Sasquatch in tank lift pump kit with their custom made 2005 wiring harness. Its a little expensive and if I had known their was only 2 wires to add, I might have just got the Carter Ram pump form Rock Auto for $120.

That said, the Sasquatch kit with harness is plug and play and comes with a great instructions, so I went with it for ease of install.