Hi, any help on this appreciated.
2011 Twin turbo diesel 4.4. Engine has an occasional misfire, as if holding back expecting to change gear. Indy could not trace, said leave to develop. Ihave it booked in to another indy 25th October to go through engine electrics, earths etc.
Away from home now, has not missed a beat for a month. Today started missing badly then later engine cut out altogether. Restarted in restricted mode.
Iid tool shows two faults, one is known P040D-00 (2F) Exhaust gas recircultation temperature sensor A - circuit high (indy broke sensor trying to remove it in July, don’t think it is a cause of misfire). One came up today, P0088 - 17 (6C) Fuel rail/system pressure - too high - General electrical failure - circuit voltage above threshold. That fault triggered at the same time as the engine stopped.
Could the second fault cause the engine failure or morelinely be a symptom of it? Any clues what it might be?
Faults were cleared, engine restriction went away, ran with no musfird for five miles back to the hotel.
The battery was good but replaced (95Ah Bosch) anyway in July as part of trouble shooting the occasinal misfire.
The alternator appears fine, voltage fluctuates as expected.
Any thoughts much appreciated, 250 mile journey awaits tomorrow!
Thank you in advance.

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Click image to enlarge

Monitor engine RPM with a diagnostic tool while idling or trying to start it as the symptoms suggest a failing crankshaft position sensor which won't produce any fault codes. RPM should not be zero at any time the engine is turning so if RPM drops to zero even just momentarily then replace the sensor.

The fuel pressure fault can be caused by a poor contact in a connector in an extension harness between the HPFP and the sensor, for which the fix is to bypass the connector.

LTB01083

Is it this: -

SITUATION:
A customer may express a concern that at low vehicle speed the engine hesitates or stumbles. In some circumstances as a result of the low vehicle speed the customer may report that the hesitation or stumble has resulted in the engine stalling. The engine will restart by cycling the ignition.
If the engine has stalled the customer may also express a concern that:
• The Touchscreen has changed and is now displaying the 4x4i – Terrain response/4x4 information.
• 'D' is flashing on the Transmission Control Switch (TCS) and Instrument Cluster (IC).

The failing sensor sounds plausible. Hopefully it will get me home. I’ll get it changed and get the fuel rail connection checked at the sametime next week.
Johnny

Good suggestion. However, it has missed when doing 60 or 70 and I don’t recall seeing the flashing D or terrain response changing. It was doing 50 when the engine stopped this time. If it happens again I’ll take a close note of the dash display.
If it is this what is the cause?
Johnny

Thinking back to yesterday the engine stopped a few seconds after starting yesterday, I thought it odd but no more of it.
When it cut out whilst driving I was doing 50, but it was down a steep hill so the engine may have been idling. And the fuel rail code was coincident with the stall time. I’m pretty sure the terrain response did not appear though.
Hmmm. Maybe I’ll get the fuel rail sensor work done and the crank position sensor done, I don’t like engines cutting out!

I wouldn't change the crankshaft position sensor without evidence that it is failing, which if the faultering is at idle would be easily determined if you have a diagnostic tool such as the IIDtool that can show live values.

Hi Graeme,
First of all I got home, 200 miles, without a hitch, not even a miss.
I called in to my new found indy and he agrees with you. He says in his experience sensors either work or don’t and was inclined to leave the crankshaft position sensor and focus on the fuel rail sensor. He said normally a crank sensor failure results in not starting.
I’m inclined to do both. No, it won’t prove what it was, but I can’t afford it to stop again so I’ve asked him to change both.
A few years back I had an occasional misfire on a petrol 4L petrol P38, a crank sensoe fixed that.
We’ll see the result next week.