TD5 surging or misfire.

[theinspector66]

Good afternoon to you all,
I own a 2003 Land Rover Defender TD5 90.
About 18 months ago it developed a surging or misfire in the engine.
Thinking it was a sensor, I replaced them all.
I replaced all filters.
I replaced the fuel pump.
I changed the ECU.
No joy was had.
My local land rover mechanic, tested the injectors, we replaced the injector loom. We replaced the fuel pressure regulator.
No joy was had.
In desperation, we removed my engine and replaced it with another TD5. The problem continued.
We replaced the red wiring harness from the ECU to ALL of the sensors.
No joy was had.
I have recently replaced all of the fusible links and the spade fuses.
We have ordered all new genuine relays and these will be changed on Monday.

If you have had anything similar, please let me know, we are running out of options.
Thank you.

[Graeme]

What boost components, if any, from the original engine are still in use? Turbo to I/C hose? Turbo? Wastegate actuator? Does it have a boost modulator like the D2 TD5?

[Bazzle218]

I take it there are no codes coming up when you have had it read. Perhaps call in and have it read at Mark Dixon Autos. (matty) I know he has all the gear to read fault codes. He may be able to suggest something. Just throwing parts at it is going down the rabbit hole.

[scarry]

One of the TD5 D2s we had did that,it was the MAF or MAP sensor from memory.
Always did it at higher revs.

[discorevy]

In desperation, we removed my engine and replaced it with another TD5. The problem continued.
We replaced the red wiring harness from the ECU to ALL of the sensors.
No joy was had.


I've heard of the parts cannon, but this is next level stuff..... Parts ICBM maybe?

Through any of this, was there any fault codes, data logging or live value testing done?, if so, what fault codes, if any, came up?

[shack]

I've heard of the parts cannon, but this is next level stuff..... Parts ICBM maybe?


With failed guidance system.

[Markf]

Hmmmm. Seeing as you have replaced almost everything I can only think that it may be a blocked or crushed or crimped or something fuel line.
Another straw to clutch at could be the TPS (throttle pedal)
That's all I have to offer.

[gromit]

Bit of a long shot but......

We owned a Mitsubishi Delica some years ago that developed a 'misfire' which was worse first thing in the morning.
Whenever I got home and SWMBO made me take it out (vehicle still hot) I didn't get the problem.

Took it to a diesel specialist and after a test costing $200 was quoted $1K to remove the injector pump, $1K to fix it and $1K to re-install (The Delica is a pain to work on)

Searched the Delica forum and it turned out to be the alternator failing and sending electrical noise down the drive-by-wire system, apparently a common fault.
Worse after a cold start as the battery voltage had dropped and the alternator was charging.

Replaced the alternator and all came good.


Colin

[Tombie]

Bloody hell 🤣

Did you try another ECU?
Fuel pump flow and pressure checks?

Parts Cannon be damned!!!

[gruntfuttock]

I had something similar, but NOT the same, replaced injector harness plus other things, no good, finally I cleaned the wires between the injector harness plug on the motor and the ECU, and it came good.
Note to self, change harness every 100,000Kms

[fender95vnt]

I had a similar if not the same experience with my 2004 TD5 90.

Apparently the issue is the fuel map. There is a Landrover upgraded map which reduced the problem with mine significantly.

It has something to do with the emissions when idling so they run it on less cylinders when coming to a standstill to reduce the emissions.
I believe it was only on some of the later ones that had this particular map.
Hope this helps
Cheers