Freelander TD4 Engine Knocking Noise.

Hi All

I started having a problem ith my 5 years old (circa 75,000 miles) 2.0 litre TD4 last year, when after a long drive (Harrrogate to Norwich and Back) I noticed a knocking noise/rattle in the engine bay. I took it to our local Landrover Specialist http://www.discovery-centre.com/.

They told me that they could not find a fault and to let it develop as it was intermittent. After a month or 2 it started to get worse and the car became virtually undriveable. The knocking began when feathering the engine, but got to the stage where white/black smoke was belching out of the exhasut with a continuous rattle/bang as soon as the accelorator is pressed.

I returned to the garage and they found a fault on 2 injectors which were replaced. I collected the car and drove off pleased with the job done.

Then, the problem returned and was as bad as ever.

I returned to the garage, who were amazed, and had the car for a few days, before ringing me with no real answer. The fault codes were being showen either stationary or whilst beign driven, but the noise was still there.

The owner suggested I replace the other 2 injectors and hopefully that would solve the problem. Again picked it up, and all seemed ok, but after a day of light driving, it returned.

The garage suggested a software upgrade, and that ddin't help.

I think they have tried hard to solve my problem, but are at a loss as what to do.

My car is now sat on the drive, as I limped home today with smoke pouring out of the back of the car and the sound of a machine gun coming from under the bonnet.

Any ideas please???

I forgot to mention, when the noise happens, you can feel it through your accelorator!

update....a neighbour who is a mechanic has told me that it is not running on all cylinders and suggsted a compression test?

Of the garage have done a proper diagnostic they would have checked compression - it assesses the load on the starter motor to see if the compression is down - clever eh!

I have just had mine diagnosed - useful exercise - no faults do some piece of mind. Did your garage do this ?

be VERY careful doing a compression test on a doozil.
A leak-down test is betterer.

I don't know if they did a compression test or the leak down test, but I will ask them tommorow.

The Mad Hat Man said:

be VERY careful doing a compression test on a doozil.
A leak-down test is betterer.

Click to expand...

What do you mean by that? My guy had a computer that fitted on the steering wheel then he hooked up to the diagnostic plug and went through a series of procedures on was compression test where hr simply cranked the engine over and it resulted in a reading for each cylinder - easy

What is a leak down test and how is it done?

not sure if this will help you, but here are some simple things to check:

1) When i had the same symptoms as you - black smoke, machine gun sound - it turned out to be caused by my fuel rail pressure sensor and wiring harness (not sure why or how...the cleverer ones here might be able to explain). So, why not try removing the connector, cleaning the contacts a little (i also very gently bent the pins on the sensor a little so there was more contact), and seeing if that helps. Takes about 5 mins to do.

2) The smoke is a bit suspect, but for noises, the crankshaft pulley tends to be a real amplified baby rattle. Taking the splash shield off (5 mins) will let you check its condition.

let us know how you get on

angeloc said:

What do you mean by that? My guy had a computer that fitted on the steering wheel then he hooked up to the diagnostic plug and went through a series of procedures on was compression test where hr simply cranked the engine over and it resulted in a reading for each cylinder - easy

What is a leak down test and how is it done?

Click to expand...

ooooo - explain how he can do that then? what pressure sensors did he use? you can read cylinder pressure thru the diagnostic plug? crikey - yu learn something new every day






or he was telling yu a load of bollix!

The Mad Hat Man said:

ooooo - explain how he can do that then? what pressure sensors did he use? you can read cylinder pressure thru the diagnostic plug? crikey - yu learn something new every day






or he was telling yu a load of bollix!

Click to expand...

From what I understand and in simple terms there is a measurement made of the load put on the starter motor as it turns over the engine - in this cycle the engine is prevented from starting ( perhaps the injectors are switched off) this is compared against a value - I suspect some sensing of the state of the starter motor must be made and then the difference on load equals the state of the compression - this is done in a matter of a couple of minutes and comparative readings are presented - if one is down it would show up as a lesser reading.

I think that is what he was saying to me - the kit is not cheap though - thousands of pounds.

I go along with Defunct, check out threads for the crankshaft pulley. It does make a heck of a clatter and is purely mechanical so it cant be found with a computer.

The Mad Hat Man said:

ooooo - explain how he can do that then? what pressure sensors did he use? you can read cylinder pressure thru the diagnostic plug? crikey - yu learn something new every day






or he was telling yu a load of bollix!

Click to expand...

Nah not bollix....

You can use crank sensor impulses to measure the time taken for each compression stroke.

The ECM does the same on power strokes to correct imbalances between cylinder outputs and compensates by fractionally altering individual injector opening times.

Chaser said:

Nah not bollix....

You can use crank sensor impulses to measure the time taken for each compression stroke.

The ECM does the same on power strokes to correct imbalances between cylinder outputs and compensates by fractionally altering individual injector opening times.

Click to expand...

Well cool eh! And in my youth we just stuck our thumbs over a spark plug hole!!!