Narrowing down cause of vibration - can I pick your brains please?

My TD5 90 had steering wobble, which I think is now resolved by new swivel bearings and steering components. However, it has recently developed a vibration which I can feel throughout the vehicle.

Symptoms:
- vibration under load (acceleration) in 3rd, 4th and 5th gear. Not in 1st or 2nd - even high revs in 2nd getting up to around 50kmph.
- vibration reduces massively when not accelerating though not entirely.
- when under load engine loses power for a split second sometimes though not always
- sometimes the above feels worse, other times not

Reading online it seems it can be either the drive-train or the engine. Prop-shafts have been replaced recently for brand new ones but I don't remember feeling this vibration after collecting the car initially. The car was remapped at this time as well.

Just an hour ago I checked the red ecu connector and it is covered in oil...could this therefore be the cause of the above problems? I took it apart, sprayed some cleaner in and try to start engine but couldn't. I've taken out the ECU and dried with a cloth as best as I could and left to dry until the morning. I will give it a go tomorrow.

I'm thinking about buying a stock ECU to have in reserve, is there a reputable company I can buy from?

What are your thoughts on the above and what would you suggest I do/try next please?

mikerajjers said:

Just an hour ago I checked the red ecu connector and it is covered in oil...could this therefore be the cause of the above problems? I took it apart, sprayed some cleaner in and try to start engine but couldn't. I've taken out the ECU and dried with a cloth as best as I could and left to dry until the morning. I will give it a go tomorrow.

Click to expand...

Engine Harness is the problem from the engine oil leaking into the harness that trickle through to the ECU plug. Replacements are cheap enough. If you went down the cleaning the plug route it wouldn't last long and return. TD5 are known for this issue with case history. Props might have a balance plate to remove vibrations. Also tyre could be out of true or lose of lead weight.

Yes, I suppose it could be something to do with the oil in the electronics. Sometimes as well as showing 'peak charge long' errors on the Nanocom, when the loom is filling up with oil it runs a bit rough with consequent vibration.

I've often thought of getting a spare ECU to have as an emergency one. Trouble is, they're a bit expensive. Just google the relevant part number and there's generally a variety of second hand ones on Ebay plus supposedly 'new' ones from the usual major Land Rover parts suppliers. Or I could see about getting my duff one repaired I suppose.

Change the injector harness, clean out the oil from the red plug and remove the rubber seal (from the red plug) so the oil drains away and does not get into the ECU.

That should cure the fault although it can take a couple of weeks for the oil to stop appearing at the red plug.

lightning said:

Change the injector harness, clean out the oil from the red plug and remove the rubber seal (from the red plug) so the oil drains away and does not get into the ECU.

That should cure the fault although it can take a couple of weeks for the oil to stop appearing at the red plug.

Click to expand...

Brain was on sabbatical Injector Harness was meant say is the problem as the oil seeps through to the ECU causing the erratic faults.

I've ordered a new harness and gasket. Hopefully that will improve the ride. I'll check the drivetrain as well though.

My red plug was full of oil, l decided to dismantle the ECU (not so easy to get the lid off) and it was completely dry inside no oil at all.
But l had experienced no running faults.