TD5 misfire / smoke

[thermidorthelobster]

I've had some misfiring on the Disco when very cold over the winter, only on startup.  Once it warms up (10 seconds max) it's fine.

But this morning I started up and for a couple of seconds it was misfiring badly (I'm guessing 2 of the 5 weren't firing).  Then it went up to 4 out of 5 firing.

But as I drove off down the road I was belching out quite a lot of white smoke.  At the traffic lights it was enough for the car behind me to disappear in the cloud.  At the next set of lights it was running smoothly but spat out some black smoke just by way of a change.

Coolant is fine, so I don't think it's burning water.  I've had the ECU loom replaced cos it was leaking oil;  I haven't yet tried a different ECU as it's hard to predict when it's going to happen.

Any other points worth looking out for?  I'm taking it in on Thursday to get it looked at, but pointers welcome.  When I leave in the mornings the neighbours must think it's Del Boy's Reliant Robin.

[Hightower]

When I had these sorts of symptoms it was because the sensor on the inlet manifold was clogged up.  Poor old ECU didn't know what to do with the readings!!

[andycwb]

What was the diagnosis?

[thermidorthelobster]

I don't know yet, they've still got it.

Steve mentioned that TD5 head gaskets sometimes exhibit this sort of behaviour on their way out.  In which case hopefully they can just fit a new one without having to skim the damn thing.  But as of 16:30 they'd not got to the bottom of it.

They're also waiting for a new aircon pipe to be delivered, as one of mine had fractured.  I wonder where the fluid went?  :?

[andycwb]

Well I can answer the air-con bit: any liquid in the system will have evaporated, leaving just the residual oil behind.

Hope they get it sorted soon.

[thermidorthelobster]

Got it back.  Aircon is fixed.  The smoking is more of a mystery.  It doesn't look like it's the head gasket;  the only way to tell for sure is to take the head off and if you're going to do that you might as well replace it anyway.

It had a new MAF a few months back so they've swapped that for a KGU to see if that makes a difference.

They've also flashed the ECU to the most recent Land Rover map, and loaded the newest Autologic upgrade over the top.  It drives differently; the throttle is mapped more linearly, which made it feel more docile to start with, but actually the power's still there, it's just not quite as sensitive as it was.  This will probably prolong the life of the transmission.

Time will tell if the smoking's any different.

[smith335]

whats a  KGU ?
i had my maf sensor changed a few months ago, just wondered what the KGU is.
cheers

[thermidorthelobster]

Sorry, a term from when we used to manufacture servers.  "Known Good Unit."

[smith335]

thanks for letting me know,i thought it was some thing like that.
just could not get my brain working.
cheers