Hi all I am new to the site and I am in the UK with a UK spec wrangled jk 2.8 8crd. My problem is if I try to rev the jeep it just coughs and splutters like it is choked, knocks (diesel knock) and puts out plumes of bluey white smoke. I have checked the turbo, egr, throttle body, turbo actuator and turbo hoses and all are ok. If i unplug any one injector it will misfire and rev as best it can and No smoke or knocking. Reconnect the injector and the problem is there still. If i try to drive it it goes into limp mode and I get turbo under boost code. I have put a new fuel filter on and the stock filter head was dry, that is no signs of leakage. The filter is located under the driver side in front of the fuel tank. If i unplug the Mercedes logo sensor, I believe it's a map sensor it revels a little better but still chokes and knocks. I did a spill back test and all injectors were identical in how much they spilled back. The knocking under load suggests running lean. I am not getting any codes unless I unplug things. The fuel rail pressure tops out at 14000psi and slowly drops to about 11000psi. I've read it should get to 23500psi. Quite a drop. If the rail pressure relief valve is failing would it not set off a trouble code? Also the fuel quantity solenoid or moron valve was failing again would I get a code. No codes except under boost if I press the throttle. If i feather the throttle i can get it to rev to 3500rpm and No more. So to me it looks fuel related in some way. Anyone had anything similar happen? Any thought would be appreciated as I am running out of ideas. By the way when I can get it to rev to 3500rpm it sounds sweet as you hear the turbo boost and if I press the throttle full there is no change in revs. All said I can't drive it as it goes into limp mode as soon as you press the throttle hard.
Regards
Jeff.
I have had it 8 yrs and this is the first fault I have had with it.

Well, first question, do you have a lift pump in or near the tank? After it has been running for a minute, if you pump the plunger on the fuel filter head and open the bleeder, do you get any air out of it? Air-in-fuel problems are usually where we start with issues like this and work our way up from there. This could have been caused by a sudden break or crack in one of the fuel supply lines, even if it isn't leaking externally.

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2006 Limited CRD: Frankenlift II, Fumoto Drain Plug, DIY Stage 1 Tune, In-Tank Lift Pump

Yeah there is a lift pump in the tank. The stock fuel head does not have a priming plunger. Apparently it's self priming. From all the research I've done there ate subtle differences. The lift pump works too as I changed the filter a couple of days ago and it started up straight away and I let it idle for at least 10 minutes. The problem was still there. Any ideas would be greatly appreciated though

I do not understand you saying that the fuel filter is on the driver side in front of the fuel tank or is this part of a Lift Pump setup?

Your RHD CRD should have the fuel filter head which is a Raycor filter head....may be slightly different to the USA models...the owners there fitted a slightly different Raycor head I believe...in the engine bay on the LHS up against the firewall. The CRD TECH ONLY site has a writ-eup on how to install the Raycor Head and how to prime it.

Have you replaced this filter and when you pump the plunger to get air out does the plunger action get hard?

That said air in fuel problems would probably not give the symptoms that you have and normally do not post codes.

The MAP Sensor is on top of the intake manifold just to the left of this fuel head as you look back towards the rear of the engine.

Read SAMS NOOB GUIDE for nice pictures of where everything is located and for advice on how to remove and clean the MAP Sensor...treat it with care and spray it with Brake Cleaner.

Also check the write-ups on how to check if the Turbo Vane Actuator is operating properly.

Edit to add: I see that you have just posted some new info on your Lift Pump and the Fuel Filter Head....I have never heard of a self priming head....could you maybe post pictures?

Try the ausjeepoffroad.com site.....they will have lots of members there with the identical Jeep as yours!

Maybe your EGR is jammed in the open position....check for advice on how to do this...my 2002 Export CRD has a different system.

Also there is an FCV flap inside the throttle body that can jam shut....this flap can be removed.

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2002 Export CRD

Note that his is a JK Wrangler, so it will be a bit different than the setup on a Liberty.

Good point! Hopefully some of the setup will be the same

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2002 Export CRD

How do I post a picture on here. All are on my phone
Regards
Jeff

i have no expertise with UK CRD model but im guessing that something is restricting fuel delivery ? so get in touch with BOSCH fuel injection shop to choose the best idea , it my be just simple as faulty fuel rail pressure sensor ? or MPROP valve , or injectors need to be tested ? i know some fuel injection shops are tight lipped , they dont want to tell us short cut fixes

Thanks for the reply I am going to test the rail pressure relief next and probably replace the end prop valve then if that doesn't work pull the injectors to get them tested.
Regards
Jeff

Your original post states that you are getting a p0299 underboost code. Start there by replacing the MAP sensor on top of the engine.
Apparently you are able the read fuel rail pressure. Although it seems low, this is a characteristic of limp mode.
Dont go digging into the injection pump, injectors, or fuel rail yet.
Start on the low pressure side.

Open the bleed screw on the fuel filter head. Pump the hand primer. Anything other than a solid stream of fuel squirting out means that you have a air in fuel problem.

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U.S. Army Retired

Low fuel pressure might be because it is in limp mode. Need to fix the cause of limp mode first.

Here is a pretty good reference on troubleshooting the fuel system on our Jeeps: https://oregonfuelinjection.com/service ... agnostics/

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My collection of CRD's:
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2006 Light Khaki Metallic Clearcoat
2006 Inferno Red Crystal Pearlcoat
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2006 Gold Limited
2015 Black Ecodiesel
2015 Black Ecodiesel 2

You have to save them on a hosting site that allows 3rd party linking, such as Postimage (free) or other.
Then put the link between the bracketed commands "[ img][ /img]"

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