Bont Boy · Apr 12, 2019

I'm desperate for some help here. My 2005 freelander TD4 will start and idle fine but as soon as you try to increase the revs, it cuts out. The day before the problem started, I had removed, overhauled and re-fitted the starter motor. I'm sure this is just a coincidence. I have taken the starter motor back out and checked that nothing around it has been disturbed. I've tried a new crank position sensor and fitted 4 new injectors. I didnt really suspect the injectors as prior to the issue it had not been smoking or having any running problems but leak off test showed 1 and 2 injectors leaking so I replaced all four with a set that I had. The fault remains exactly the same.
Any ideas?

Thanks,
Bont Boy

Nodge68 · Apr 12, 2019

How about checking the condition of the connections on the fuel rail sensor?

Bont Boy · Apr 12, 2019

Thanks for your reply. They look ok. I have previously fitted the wiring loom overlay. I guess the sensor could have failed but wouldn't it bring up an engine management light?

Nodge68 · Apr 12, 2019

Bont Boy said:
I have previously fitted the wiring loom overlay.

Was the sensor replaced at the same time as the overlay harness?

Bont Boy said:
I guess the sensor could have failed but wouldn't it bring up an engine management light?

Not always.
Can you get the live data for the fuel rails?

andyfreelandy · Apr 12, 2019

Mine had the fuel pump relay drop which cut the engine at a certain number of revs. The fault was the crank sensor so check wires not damaged when you did the starter and see, by listening, if fuel pump relay cuts. It is by driver's knee.

Bont Boy · Apr 12, 2019

andyfreelandy said:
Mine had the fuel pump relay drop which cut the engine at a certain number of revs. The fault was the crank sensor so check wires not damaged when you did the starter and see, by listening, if fuel pump relay cuts. It is by driver's knee.

Thanks. I'll give that a try first thing tomorrow. Was yours able to idle ok?

Bont Boy · Apr 12, 2019

Nodge68 said:
Was the sensor replaced at the same time as the overlay harness?

Not always.
Can you get the live data for the fuel rails?

I didnt replace the sensor when I replaced the overlay about 18 months ago. It has been running fine. I'm going to run a diagnostic on it hopefully tomorrow so I'll get live data then.

andyfreelandy · Apr 12, 2019

Bont Boy said:
Thanks. I'll give that a try first thing tomorrow. Was yours able to idle ok?

Mine reved to about 4k then cut but as you worked on starter and space is tight check the thin wires are ok for similar if not identical fault.

Bont Boy · Apr 12, 2019

andyfreelandy said:
Mine reved to about 4k then cut but as you worked on starter and space is tight check the thin wires are ok for similar if not identical fault.

I have checked wiring and replaced crank sensor but will certainly check again. I was considering replacing o-rings in the fuel pressure regulator. Do you know if low pressure trips the fuel pump relay too?

andyfreelandy · Apr 12, 2019

If common rail goes low pressure I believe lp pump is cut by ecu to protect hp pump running with insufficient fuel and damaging it. Live data would help you if you can get a suitable diagnostic tool.

Bont Boy · Apr 12, 2019

andyfreelandy said:
If common rail goes low pressure I believe lp pump is cut by ecu to protect hp pump running with insufficient fuel and damaging it. Live data would help you if you can get a suitable diagnostic tool.

So the o-rings in the fuel press regulator could still be giving me the problem then? I’m plugging it into diagnostics in the morning so hopefully will know more then. Thanks for your help

Nodge68 · Apr 12, 2019

Bont Boy said:
So the o-rings in the fuel press regulator could still be giving me the problem then?

Normally if the HP regulator O fails, the engine won't start. The HP regulator stops fuel pressure bleeding back to the return line when activated. This is why a split O ring stops the rail pressure from building, preventing the start, as the HP fuel is always bleeding back, regardless of the regulator function.

I'd look at the live data for the low and high fuel rails. As Andy said. If the low rail drops below a set threshold, the ECU kills the injectors, to avoid HP pump damage.

Bont Boy · Apr 12, 2019

Nodge68 said:
Normally if the HP regulator O fails, the engine won't start. The HP regulator stops fuel pressure bleeding back to the return line when activated. This is why a split O ring stops the rail pressure from building, preventing the start, as the HP fuel is always bleeding back, regardless of the regulator function.

I'd look at the live data for the low and high fuel rails. As Andy said. If the low rail drops below a set threshold, the ECU kills the injectors, to avoid HP pump damage.

Thanks for your reply. Do you know what the LP and HP pressures should be?
I guess it could be LP pump or filter then.

Nodge68 · Apr 12, 2019

Bont Boy said:
Thanks for your reply. Do you know what the LP and HP pressures should be?
I guess it could be LP pump or filter then.

The LP rail should be around 350 Kpa, preferably 360 Kpa at idle.

The HP rail will be 25,000 Kpa to 28,000 Kpa at idle.

Bont Boy · Apr 13, 2019

Ok. This is my idle data.

And this is a capture of just before it cuts out at 1000 revs.

Any thoughts?

andyfreelandy · Apr 13, 2019

Engine speed is lower in 2nd photo!! What happens as it cuts?

guineafowl21 · Apr 13, 2019

andyfreelandy said:
Engine speed is lower in 2nd photo!! What happens as it cuts?

I was thinking the figures were slow to update. Perhaps scan again and leave more time?

Bont Boy · Apr 13, 2019

andyfreelandy said:
Engine speed is lower in 2nd photo!! What happens as it cuts?

As soon as I press the accelerator it cuts out. If I’m very gentle I can get revs to rise to just under 1000 before it cuts out. Sometimes it starts “hunting” and if I press pedal then, it makes no difference to engine speed.

guineafowl21 · Apr 13, 2019

Can you cut out some of the readings, such as temperature and pedal demand, so that the interesting figures update faster? Try that, and gently revving. Perhaps a video?

marjon · Apr 13, 2019

Would something show up better on a graph?
It seems to show you have that option.
J

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