diesel rough idle

[barty]

Hi, any pointers why my freelander td4 has started to run rough at idle, it really shakes the whole car now. sometimes it ticks over nice and smooth but other times its rough
Thanks

[dave21478]

Well, you tell us nothing about the car, so....start at the basics. Service it. Filters, oil etc. Unrelated to idling, but probably needs changed anyway....remember the wee filter that looks like an inline petrol filter from a lawnmower (Thats exactly what it is!) that hangs down the back of the engine under the brake servo. One end is connected to a rubber hose, the other end is left open to air.
Also, remember the wee breather filter that is inside the rocker cover. Take off the torx screws holding the inspection plate down behind the injectors. This is VITAL as if it gets blocked it raises crank case pressures and causes all sorts of problems. Fit a new replacement or better yet, bin it all and fit the parts from a BMW 320D - part number is easily found on the landrover forums.

After that, look at the air flow meter, fuel pressure sensor and wiring harness, clogged up EGR valve, injector leakback....... There is an awful lot to go wrong on these engines.

[retrowrongun]

Once you have checked the basics and also ruled out dodgy injectors try this
Reach under the induction hose which feeds the air filter box just above and behind the EGR valve there should be a multiplug. This is the fuel rail pressure sensor, disconnect it.

Start the engine, it should start with the plug disconnected.
If you have a smooth idle then you are likely to have the same issue that I had

Stop the engine and reconnect it, as I was advised not to drive the car with it disconnected.

What has happened is the contacts in the plug have corroded and giving the impression of lower fuel pressure, the ECU compensates by overfueling then as the idle revs increase it cuts the fuel, causing the engine to hunt for a stable idle.

Now ring your local Landrover dealer and ask for a Fuel Pressure Sensor Overlay Wiring Kit for the TD4 Freelander, also ask them if they could give you the technical bulletin which details the procedure. Cost of the kit was about £35 including VAT.
Its quite easy but you need to cut a hole in the Engine Management outer box to route the wires through and also replace 3 pins in the ECU connectors, it took me 30 minutes to do.
I have heard on other forums people spending weeks/months and several hundred pounds trying to fix this issue. Do this first.

[barty]

Hi, thanks for the responses, the car as stated is a freelander Td4 2005 which I'm told has the BMW diesel engine. I bought it from a dealer a few months ago and was told it would be serviced before i took it ?. It runs fine but its just the tick over thats has the problem.
retrowrongun, thanks for that info, i have heard of this kit before but i thought i would see if anyone else had any ideas first

[Kierenbrown]

DMF?

[sowen]

Sept 16, 2013 17:18:51 GMT retrowrongun said:

Once you have checked the basics and also ruled out dodgy injectors try this
Reach under the induction hose which feeds the air filter box just above and behind the EGR valve there should be a multiplug. This is the fuel rail pressure sensor, disconnect it.

Start the engine, it should start with the plug disconnected.
If you have a smooth idle then you are likely to have the same issue that I had

Stop the engine and reconnect it, as I was advised not to drive the car with it disconnected.

What has happened is the contacts in the plug have corroded and giving the impression of lower fuel pressure, the ECU compensates by overfueling then as the idle revs increase it cuts the fuel, causing the engine to hunt for a stable idle.

Now ring your local Landrover dealer and ask for a Fuel Pressure Sensor Overlay Wiring Kit for the TD4 Freelander, also ask them if they could give you the technical bulletin which details the procedure. Cost of the kit was about £35 including VAT.
Its quite easy but you need to cut a hole in the Engine Management outer box to route the wires through and also replace 3 pins in the ECU connectors, it took me 30 minutes to do.
I have heard on other forums people spending weeks/months and several hundred pounds trying to fix this issue. Do this first.

I've never heard of this, and have had a hunting revs issue on my 75 with the same engine for a few years now. I cleaned the contacts last night and it didn't hunt on the way to work today, hopefully that is the issue I've been having

[retrowrongun]

Nice one sowen hopefully have helped someone then lol

[sowen]

Sept 17, 2013 13:04:05 GMT retrowrongun said:

Nice one sowen hopefully have helped someone then lol

I hope so, it's been to a garage and put on the diagnostics, for them to charge me the privilege of telling me what I already know doesn't work, and yet it continued to hunt and sometimes 'missfire' entirely. Time will tell I guess

[retrowrongun]

Please update the thread if it solves your problem as will help others in future and glad to help mate

[barty]

I was about to try this today but rain stopped play. Got a busy day tom but if i get time ill try this. Let you know if it works