TD5 Missfire.

Afternoon all!
Got an odd one here, 2003 Defender TD5 with 260,000 miles on it & up to now, pretty much trouble free.
Fault that has developed recently is as follows.
Starts great & runs fine on all five for about 15Min until it starts to warm up, then a misfire appears. Have had various scanners on it & got a whole array of strange results. A whole lot about Aircon (which it doesn't have) various injector faults & crank sensor signal issues. Changed the crank sensor & cleared the faults. Started great Then the misfire came back on different injectors according to scanner. Cleared those & tried again, started great then misfire returned on different injectors according to the scanner. Only up to 2 injectors & can be any combination or a single one. Had a look at the plug into the ECU, bit of oil there but didn't look to dramatic.
Put a new Fuel filter on Aug 2024 so going to swap that incase we got some dodgey fuel from somewhere.
Must admit its got me scratching my head a bit, so much so, i am in danger of getting splinters under my fingernails if a scratch it much more!
Anyone got any ideas/suggestions on this one?
Many thanks all.

If there’s any oil in ecu, it needs the injector loom replacing and clean ecu port best you can

Thanks for that, Is the injector loom one piece to the ECU or is it broken down into several sections? Not a massive amount of oil in the ECU port or plug but already cleaned that out with Brake cleaner & Electrical contact cleaner.

The injector loom is in the top of the engine underneath the rocker cover, it's easy to change.

Sounds good & the sealed one looks like a godsend. Presumably, the residual oil in the harness from the injector loom to the ECU isn't to much of a problem? And i cant figure out why the problems only show up when warm & not from cold.

Paxmanmerv said:

Sounds good & the sealed one looks like a godsend. Presumably, the residual oil in the harness from the injector loom to the ECU isn't to much of a problem? And i cant figure out why the problems only show up when warm & not from cold.

Click to expand...

Don't know but you might aswell change it being pretty cheap.

Paxmanmerv said:

Sounds good & the sealed one looks like a godsend. Presumably, the residual oil in the harness from the injector loom to the ECU isn't to much of a problem? And i cant figure out why the problems only show up when warm & not from cold.

Click to expand...

If the harness is the issue, and it was my initial thought as well, oil can get into the ECU. I would take it out and stand it plug side down overnight on some paper towel and see if any oil comes out it. You can open it up as well, but I’ve never done it. I’m sure they open them up to chip them so it can’t be a big deal to do so.

Thanks for that, will give it a shot if a new harness doesn't cure it.