2011 JK 2.8 CRD - Hard To Start

[kim.beveridge]

Hi. Yep glow plug goes out after couple of seconds only.


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[Stevil]

Have you tested the intank fuel pick up pump ??

Most of ur symptons fit this fault

[kim.beveridge]

Hi. I haven tested t specifically. I can hear it working but maybe it has some problem. How can I test that it is working adequately.


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[Stevil]

Tank needs to be dropped out and pump tested, u should be able to hear it when u turn ur key on before starting

I had a rusty connection on mine and when i hit a bump my card would stop briefly stop running hit another bump and be fine

When i stopped it wpuld crank but not start, jeep failed to diagnose the problem it was just 1 day i stuck my hand ontop of the tank as i suspect wiring wss the problem, yep my crd cut out.

Just an idea and def worth checking, our motors need this pump to keep pressure up its not just for starting, if its got an issue it could.cause what ur problem is. Its a Delco pump and pretty much fitted in ecwry chrysler diesel jeep going around

[DarrenR]

As already mentioned...
not having a diagnostic tool and someone that actually knows how to look at the data is a problem.

Typically on a problematic JK CRD (I basically only work on Jeep, Land Rover diesels) taking it for a drive and recording data is the only way to do it on any common rail diesel. Fuel pressure issues, as in a faulty fuel pressure regulator and or fuel pressure sensor are a common one, as is the fuel pressure solenoid on the back of the high pressure pump, not just JK but all modern common rail diesels I work on, I keep them all in stock. But fuel pressure issues will cause a fault code related to the lack of pressure etc.

Another oddity on a JK is a poor earth, follow the earth lead down from the battery and remove clean all fixing point. A (often just loose on the body) poor earth will cause this odd starting on a JK CRD, it can also throw up a fuel pressure fault at times too.

My "guess" is the earth issue.

Just a side note...
Take care when doing any work on the high pressure side of the fuel system when running, the rail & injector pressures on any common rail diesel run at idle round 3000 - 5000psi, which is enough to inject diesel fuel into your skin.

Regards
Daz

[DarrenR]

Originally Posted by kim.beveridge

So I also started getting this hard to start issue. Read some of the past topics on the forum which helped.

I did a test this morning by listening for the fuel pump with ignition on. Pump was working but went for a long time (at least 10 to 15 seconds) before it turned off, then I tried to start and started first time like it should.

Does this mean that fuel system is loosing pressure over night and that's why it is taking that long to bring the pressure back up?

Or.

Fuel priming pump is on way out and taking long time to get system up to pressure ?

Or.

Some other fault causing pressure loss over night?

Thanks
Kim


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Kim,
Is your hard starting issue on a JK CRD or the mighty KJ? if JK then see my previous post, if KJ ..... u should really go and ask in the KJ part of forum where all the cool kids hang out!

Your general questions; (generally answered)
*Pump runs for 15 - 20 sec - Then it turns off if the engine hasnt started, by design, thats correct.
*Fuel pressure drop off on engine shutdown happens a few seconds after, keep in mind the fuel system on a common rail is a constant return to tank loop, the injectors take what is needed.
*Fuel pressure on the low pressure side comes up within a few seconds of ignition on.
*Fuel pressure on the high pressure side (output on high pressure pump, common rail, injectors) comes up as the engine is cranked, once pressure is within spec the injectors are fired by the engine computer.
*So as above, when all off, pressure will drop off to zero.
*if you mean pressure loss as in you think its sucking in air thus making hard starting in the morning, then yes the "lift" pump or "low pressure" pump in the tank maybe loosing prime, was pretty common on Jeeps of old such as the WH grand cherokee, and others, not so much on JK.
*Glow plugs continue to be turned on and off as required even after light has gone off and also while engine is running.

Regards
Daz

[Stevil]

Darren would it be possible for gunk to partially block the pick up pump in the fuel tank ?