Defender TD5 Injector Harness Replacement

[Rannsachair]

The TD5 Defender I have run for the last 15 years finally succumbed to the dreaded oil in the harness fault: started to misfire and I found oil at the ECU plug under the drivers seat.

It is a common fault and a relatively cheap fix: about £30 for a new harness and rocker gasket.

So disconnect battery and off with the acoustic shield and breather pipe:

Remove the rocker cover bolts and cover:

old harness just unclips in seconds:

New harness in:

New Rocker gasket:

then torque the rocker cover back down, breather on, acoustic shield back, reconnect battery:

Started first time, easy enough job, took just over 30 minutes not rushing, rain just started as I put the cover back on the engine. Lets hope this one is good for another 18 years.

 

[Rrobson]

Ah the old td5. I only had a brief experience with one of those in a discovery, it sounded half decent for a diesel but it was gutless.
Btw who’s daft idea was that to run the injector wiring through the middle of the rocker cover???

 

[awemawson]

It's a stupid design - oil pools round the output seal which should face upwards even if the cable run isn't as neat.

I had mine done about 3 years ago

 

[armalites]

Lets hope this one is good for another 18 years.

Don't leave it that long, just change it every 2-3 years. They don't cost much

 

[Kayos]

I found it a nice easy job, threw the old loom id kept "just in case" last week.

Sold the D2 6 months ago

 

[armalites]

If you read the tech bulletin it says something along the lines of "If the customer doesn't want to spend too much money you can clean the loom and seal the top of the connectors and reuse"

 

[m_c]

We used to just unplug the loom, clean out the contacts with brake cleaner, refit it, and it would last another couple years before any misfiring returned.
That was on working defenders that were out at least 5 days a week.

 

[Bullet2012]

acoustic shield

I always knew it as the beautification cover.

 

[Wozzaaah]

Did ours (D2) a few months ago, nice simple job and we’ve had no problems since.
Also fitted a new MAF sensor, anyone that tells you it’ll run as normal with a dead one is lying. Yes it will run ok but it’s a proper night and day difference when you fit a working one.

 

[dobbslc]

@Rannsachair
How does replacing the harness under the rocker cover fix the oil that's got into the ECU under the seat? Don't you have to also replace that or clean it?
Just interested

 

[Wozzaaah]

If you’re lucky it’s only made it’s way TO the ECU and hasn’t actually seeped inside it.

 

[armalites]

Did ours (D2) a few months ago, nice simple job and we’ve had no problems since.
Also fitted a new MAF sensor, anyone that tells you it’ll run as normal with a dead one is lying. Yes it will run ok but it’s a proper night and day difference when you fit a working one.

It does make a big difference, they sensor can obviously be still within measurement tolerance but so far out it will run like a dog. If you disconnect them they go to a default setting and often when you have a failing one just unplugging will transform it.

 

[Wozzaaah]

Ours was completely dead and had been for some time. It was picked up during a service but as it ran “fine” I just ignored it.
Finally decided to fit a new one and was astonished at how much better it pulls. Again, people say don’t fit cheap ones but I got one on eBay for under £20 and it works fine.

 

[armalites]

We can all argue the logic the injector harness design and from experience some vehicles suffer far less than others but the reality is the part costs £30 and you can do one in 30mins easily if needed. A bit more fiddly on a D2 but as there's less room.

I would tell anyone who buys a TD5 to just change it no matter what. They can cause all manner of bizarre issues, may be a little misfire but can cause bad start or no start and cutting out.

It's even more surprising on a D2 because the ECU sits at the same height as the rocker cover so the oil wicks along the loom,through two connectors down the block and back up to the ECU. I've seen one where the oil had been change and it wicked that quick the the oil in the red connector was clean.

You can take the orange seal out of the ECU plug which will allow it drain a little but I'll say it again the loom is £30 change it

 

[armalites]

Ours was completely dead and had been for some time. It was picked up during a service but as it ran “fine” I just ignored it.
Finally decided to fit a new one and was astonished at how much better it pulls. Again, people say don’t fit cheap ones but I got one on eBay for under £20 and it works fine.

I suspect there are loads of people driving around with under performing engines, flags no errors and if you hadn't had one before you wouldn't know. It's like you've had remap done when you change one that was faulty.

I've read that over oiled K&N filters can cause issues with them.

 

[armalites]

@Rannsachair
How does replacing the harness under the rocker cover fix the oil that's got into the ECU under the seat? Don't you have to also replace that or clean it?
Just interested

Hopefully it doesn't get into the ECU just into the connector.

I take the orange seal out(it will swell if you don't), take the plastic guide piece out and hose the connector out with brake cleaner. Make sure the ECU connectors pointing down so the fluid runs out and hose that out too. If you want to get it really clean then you'll sometime need to do it several time over a period of a few days of driving.

 

[Rannsachair]

@Rannsachair
How does replacing the harness under the rocker cover fix the oil that's got into the ECU under the seat? Don't you have to also replace that or clean it?
Just interested

I was lucky, there was just a little oil in the plug on the ecu, I sprayed the plug and the plug connection with the ecu with brake cleaner, certainly seems to do the trick. The harness in just the source of the oil as you say. if you do not catch it quick enough, it can fry the ECU

 

[Wozzaaah]

I suspect there are loads of people driving around with under performing engines, flags no errors and if you hadn't had one before you wouldn't know. It's like you've had remap done when you change one that was faulty.

I've read that over oiled K&N filters can cause issues with them.

I think ours was probably dead when we bought it. I'd always thought it was a bit flat but having never driven one before I just thought it was normal.

 

[moose]

Oh the TD5, of all the cars I have had the TD5 Disco is by far the worst, in it defence it might be that ours had been so badly neglected but, had misfire changed the leads as above still happened, but it did need changing, there are three small vacuum pipes, to the front right of the head, changed, sorted no more misfire, Also a known fault exhaust manifold warping and pulled studs out of head, I did that , head the manifold machined, new bigger studs tapping the head etc. Had a noise which was getting worse, from front of the engine could not find it. tried taking rocker cover off, disconnected drive belt, etc.

So after losing patience. Took the rocker box cover of yet again and found sticking up a errant slipper guide for the cam chain obviously not attached, to replace the cam chain on the TD5 the front of the engine has to come of as you would expect, but also the cylinder head, I kid you not, had the work done not cheap, there is a known fault that for some reason people have reported that once the head has been off and put back on engine has starting issues yep totally agree.

Having used it for a year, pulled out on to a road, went 40m and the engine went bang, would not start etc, I was on a fast A road near a bend, not happy, rolled away from bend, better but still fast road, called AA took them 4.30 hrs to move us but that is a different saga.

Because of what we had done to the car, welded rear 1/4 chassis, steering pipes, and box, and a lot of other things decided we had to keep car, bought a 2nd hand engine from Land Rover Show Kelmarsh, had the car and engine taken away and swopped.

When the guy took the knackered engine out the amount of fluid inside believe it hydraulic it self, not sure why.

New engine (to me) much better than the old but now have misfire again, replaced the cables as above done the vacuum pipes as above, still have it. I have many Land Rovers so its not that I am against them but the TD5 engine when running properly it is fairly handy.

Misses has said she won't drive the disco now, seems to have a fault on the steering, possibly a wheel bearing etc!

 

[Rannsachair]

Oh the TD5, of all the cars I have had the TD5 Disco is by far the worst, in it defence it might be that ours had been so badly neglected but, had misfire changed the leads as above still happened, but it did need changing, there are three small vacuum pipes, to the front right of the head, changed, sorted no more misfire, Also a known fault exhaust manifold warping and pulled studs out of head, I did that , head the manifold machined, new bigger studs tapping the head etc. Had a noise which was getting worse, from front of the engine could not find it. tried taking rocker cover off, disconnected drive belt, etc.

So after losing patience. Took the rocker box cover of yet again and found sticking up a errant slipper guide for the cam chain obviously not attached, to replace the cam chain on the TD5 the front of the engine has to come of as you would expect, but also the cylinder head, I kid you not, had the work done not cheap, there is a known fault that for some reason people have reported that once the head has been off and put back on engine has starting issues yep totally agree.

Having used it for a year, pulled out on to a road, went 40m and the engine went bang, would not start etc, I was on a fast A road near a bend, not happy, rolled away from bend, better but still fast road, called AA took them 4.30 hrs to move us but that is a different saga.

Because of what we had done to the car, welded rear 1/4 chassis, steering pipes, and box, and a lot of other things decided we had to keep car, bought a 2nd hand engine from Land Rover Show Kelmarsh, had the car and engine taken away and swopped.

When the guy took the knackered engine out the amount of fluid inside believe it hydraulic it self, not sure why.

New engine (to me) much better than the old but now have misfire again, replaced the cables as above done the vacuum pipes as above, still have it. I have many Land Rovers so its not that I am against them but the TD5 engine when running properly it is fairly handy.

Misses has said she won't drive the disco now, seems to have a fault on the steering, possibly a wheel bearing etc!

Yikes, mine has been trouble free bar a new turbo and fuel pressure regulator, though I on do 4k to6k miles a year and change all filters and fluids every year. I did away with the EGR system not long after I got it and I have a no Cat Janspeed big bore stainless exhaust. I understand the later engines have less issues.