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[firefighter1023]

Hi dave.  I replaced fuel inlet and return at tank to check for air bubbles. Both have no air in then. Very strange.  So I am.confused becuase the fuel head is getting air .. I think it's showing a problem with the fuel head (maybe)  but strange how no air on return pipe. 

She revs to around 2500rpm on full throttle but won't tic over now.  It's making no sense.  I think I'm missing the obvious but can't for the life of me see it. 

Any further suggestions will be much appricated.  Thanks all.

[bgbazz]

Does your filter assy have the water bowl on the bottom? If so, check and make sure the drain cock on that is tight and sealing properly...obviously drain off any water that may be in the bowl.

[firefighter1023]

Hi baz.   Going to replace fuel filter head.   Got a p0051.  More problems. Lol.

[bgbazz]

That's a strange code to get....do you still have the old/original fuel filter head to check and try before you go and buy another one?

Another thing you might try...bypass the filter  by using a short piece of high pressure hose and jubilee clips...I've done this on a Caterpillar D8 dozer and the result was positive...just don't do it for too long!

[bigjeepzj]

 
I did that on a diesel XJ with a similar problem
then fitted a ford transit filer   

[firefighter1023]

Hi guys. 

Strange!  When disconnected inlet and return from fuel filter and fit clear pipe crank NO FUEL going through clear pipe.  No attempt to start ... but when I put back to fuel filter starts on revs for a min or so then stops.   Could it be the high pressure fuel pump. AGAIN.  Arrr.  Thanks.

[bgbazz]

Don't give up yet mate. Try this...

when you have the inlet pipe/hose disconnected from the filter head, using that piece of clear hose feeding into a jar or can, turn the ignition on, but do not crank or try to start the motor....fuel should be fed from the tank as soon as the ignition is on. The lift pump in the tank is electric and should be providing fuel.
Try that.

[firefighter1023]

Hi baz.

My jeep is uk version KJ Series. We don't have lift pumps in the tank mate.  I believe it's just the fuel pump on the engine.  I know when I have cleaned the tank I haven't seen a lift pump.   

[bgbazz]

   Mine was the UK series as well and it definately had a lift pump inside the tank, but if yours doesn't have it, then I am almost out of ideas. Revert to plan A and investigate the IP.


Have a look at that service manual pdf I sent you, go to fuel system and then to section 14 - 13 and see if yours is the same (mine was).

[firefighter1023]

Hi baz. 

Going to look at manual mate.  I think if all else fails a new engine ..    it's got me totally confused.  I am think sending it to stealaship for a diagnostics 1st before engine.  Becuase I have replaced everything on the engine now and all sensors.   Just a thought!  What about pcm/ecu failure ? 

[JamesH]

I'm clueless about Jeep diesels (except a tiny bit of WK diesel knowledge) but if Bazz is correct about a pump in the tank then my experience of these lumps on the petrol models is that they love to fail, either no providing enough or any pressure when ignition is turned on or the anti return valve gives meaning no pressure being held in the system. Like I started with, no actual knowledge of this model and engine but I really don't want you to go into the new engine purchase route when it could potentially be a £100 pump and a few hours of labour to sort out.

[bgbazz]

I would be exploring every possible option before I went down the new engine route...they won't come with all the peripheral stuff which can and do go wrong.

At the moment my thought are these....engine starts and runs from residual fuel in filter housing....when the motor is running, the Main pump causes enough vacumn in the line to get SOME fuel from the tank to the filter, but not enough to let it rev very high. My redneck experience says get a jerry can full of fuel and sit it on the roof of the vehicle with a hose connected to the inlet side of the filter...use it like a siphon and remove all the air first with the primer pump on the top of the filter housing. Start the motor and see what happens...it might take a moment or two to run smoothly, but will prove or disprove the feed theory from the main tank.

[Dave69]

common rail diesels have lift pupms in the tank to prime the main fuel pump.

the jeep should be fitted with one unless they have a revolutionary design that no one else has for common rail use

[JamesH]

Sounds like the pump is definitely worth changing (assuming it's not too expensive)

[bgbazz]

common rail diesels have lift pupms in the tank to prime the main fuel pump.

the jeep should be fitted with one unless they have a revolutionary design that no one else has for common rail use

Totally agree with you Dave69....using a siphon to keep the filter charged with fuel will indicate whether the lift pump is faulty or not ( when he used the clear pipe, he stated that NO fuel was visible...that's a very clear clue by itself). Not forgetting that the height difference between the bottom of the tank, where the lift pump is located, and the filter head is something like 30 inches!

Maybe the main pump or the fuel pressure sensor is faulty and that remains to be seen, but if the lift pump in the tank is playing up and the supply of fuel to the filter head and onwards to the IP is unreliable or seriously depleted, no amount of fiddling is going to cure the problem until fuel supply is rectified.

[Mike Pavelin]

common rail diesels have lift pupms in the tank to prime the main fuel pump.

the jeep should be fitted with one unless they have a revolutionary design that no one else has for common rail use

....like for example the KJ CRD, which has a Bosch CP3 pump with both lift and high pressure pumps integrated in one unit?

[firefighter1023]

Mike .. you are correct.  There is defo no lift pump in the tank.  I have stripped the tank and no pump.   

Just a thought for you all pcm/ecu fault.  

[firefighter1023]

Grrrrr.   Tried they hose from the high pressure fuel pump to a can of fuel and still no start.   Air and fuel going back to can when stop cranking ..... could this mean another high presure fuel pump.   Arrr. Hope not.   

[bgbazz]

    The hose was supposed to feed fuel from the can down to the filter head, then to the pump...if the air is cleared and everything runs as normal, that indicates a possible leak between tank and filter head....if air bubbles persist, bypass filter head and connect hose direct to pump feed...no air and proper running indicates possible filter head leak.

Work on from there...

[firefighter1023]

Sorry for the late reply.  Been a busy week.  One quick question.  Engine is ice cold but the odb reader is saying engine coolant temp and air intake temp is 215 degrees.... very strange.  Could this be a source to the problem.  ?   ...  I really need this lady fixing for the winter.     ....   Thanks again guys for all your help.  I really do appricate it.   

[bgbazz]

  ...that's very strange! Disconnect the battery for 30 mins or so, reconnect and try the scanner again. (make sure you have your radio security code handy).

If that doesn't change things, I have no idea where to go after that.

[firefighter1023]

I totally agree.   Very strange them readings.  Possible case starting problem.  I have tried and still same reading.  Fried pcm/ ecu maybe. !!? 

[Jonny Jeep]

temp sensors are normally high resistance when cold, low resistance when hot. The temp you have indicated would indicate a possible short between the two wires going to the sensor. I wouldn't think it's the sensor itself as they normally go open circuit when they fail.

I don't know where the temp sensor is on your engine but if you locate it you can measure the resistance between it's pins. This chart is the one for TJ intake air and coolant temp sensors. It should be in the ball park of what your sensor should show. If the computer thinks temp is high it could be running lean.

PM sent which may also help.

[firefighter1023]

Thank you very much baz for that information.  I will check it tomorrow and report back to you mate.   I think all mechanical issues have been covered.   Think more electrical now.  Hope so.  Get her back on the road ready for the snow.    thanks for helping me with this problem.  I really do appreciate it.   

[scrw]

Oh been here with CRDs. Deffo NO lift pump in the UK KJ tank. It is worth fitting one, I fitted one & wired into the fuse box by passenger feet, US KJs have a tail on the loom for a pump, UK ones don't.
Pump I fitted


ALSO, fit a clear filter higher than the filter head, means you can see if you are getting air in the lines as they work upto there



Next off clean the MAP sensor in the inlet.

The following link should be all you need to know to get your jeep running, its a goldmine of info

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=54207