Oh no! TD5 Misfire on one cylinder!

For the first time ever today - had a good 30 min run to work but when I stopped, the car was shuddering and making a more tractor-like noise than usual. Cylinder misfire! Revving in neutral didn't shift it. Stopped and started the engine and it cleared straight away.

Coming home tonight, same thing - arrived home and it started misfiring. Stop/Start cleared it straight away.

Guess I'm going to have to check for oil in the loom first, but weird how a stop/start clears it straight away

Sat here thinking of other things to check - MAF sensor, low pressure fuel pump, hopefully not a dodgy injector!! (££££££)

Just had a good look...

Took the engine cover off and around the injector loom plug it's very oily. Removed the plug and although the connectors inside didn't seem to be swimming in oil, the plug itself was well oiled. Cleaned it up as best I could and sprayed some wd40 onto the connector points and into the plug.

Engine started fine, and ran fine, but I'll suppose I need another long run to see what happens.

How do you stop the oil leak? New rocker gasket? It seems to be leaking a bit down the back of the engine too (very grimey, like around the plug.) It's oily and grimey around the EGR valve, where the leaking oil has spread over it.

sussed it.

The 'loom' at fault isn't the one I've just disconnected. That's the main engine loom. The one I need to replace is under the rocker cover. I then need to allow the engine loom to 'drain' of oil by cleaning it several times until it's fine.

Crap.

hi, mine's doing the same but intermitent !!
some days fine, others every time i start it seems to misfire but clears if i switch on and off..
sound like i should be checking my loom !!!

Oh dear!

Even if it turns out to be something else, my injector loom obviously needs replacing anyway. I wonder if the new one will leak with time


Check out this page, it's very good - tells you everything you need to know!

Just checked the ECU side of the loom ahead of ordering a replacement and there's no oil there at all! So it's not oil leaking into the ecu plug that's causing the misfire!!

What else can I check myself?

mines continuesly missing now .. did you get any further ??

Lots and lots of discussions with various mechanics.....

Basically I know for a fact now that I have an open circuit fault on cylinder 1 (injector 1) which only happens when the engine is fully warm. I have it on good authority that this is almost definately an injector fault, from his experience of seeing TD5 injectors fail under the same warm engine conditions only, and showing an open circuit fault code when they go. This is contrary to my earlier scepticism about a failed injector only showing symptoms on a warm engine, and not when starting from cold.

I am going to replace the injector loom as a 'fingers crossed' exercise, just in case it cures it (it needs changing anyway), and if the problem persists, it's a new injector for me! (Well, a refurb one, anyway)

Finding a mechanic with the correct system to program the new injector's calibration code into the ECU has been a pain. As has finding a refurb'ed blue top injector

James

simon j said:

mines continuesly missing now .. did you get any further ??

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PS - Did you check your loom at the ECU end?

James W said:

PS - Did you check your loom at the ECU end?

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James

I used a very good mechanic in fact hes classed as a master mechanic and all he has ever done is land rover so if you need his number he may be able to help.

Wanagetmuddy said:

James

I used a very good mechanic in fact hes classed as a master mechanic and all he has ever done is land rover so if you need his number he may be able to help.

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Where abouts in the country? Could be interested.

Cheers
James

James W said:

Where abouts in the country? Could be interested.

Cheers
James

Click to expand...

Hes based on the M5 j5 close there anyway Worcestershire


I tend to fix the 200tdi but with the td5 I tend to take it to him rather than any garage.

What I found with ours is when is working its a fantastic car when it goes wrong it can be expensive if donr wrong

have you changed your loom yet,
just curiuos as i plan to change mine in the near future...Si

simon j said:

have you changed your loom yet,
just curiuos as i plan to change mine in the near future...Si

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Hi there.. will try and summarise this saga as briefly as possible

• Vehicle misfiring continuously but only on one cylinder, never when cold, and only when up to full operating temperature (about 10-13miles)
• Slightly oily loom at engine end, but no oil at red ECU plug end
• Open Circuit fault code reading for cylinder one. Faults cleared and returned when misfiring again
• Decided that based on the evidence above, it was most probably a faulty injector. expert help advised that "failing when warm" is a common way for TD5 injectors to go.
• Also decided that seeing as the loom was leaking just a bit, it was worth a go at changing it because it's relatively cheap (~£30), I could do it myself (easy job) and you never know, it might fix it. If it didn't fix it (didn't really think it would to be honest) I would get someone who knows what they're doing (i.e. not me) to change the injector.
• Borrowed a torque wrench to change the injector loom myself before commiting to a new injector, but the torque wrench only went down to 20NM and I needed 10NM (If I recall correctly - might be 12)
• Got fed up with the whole thing, had a mardy on for a few days. Bought a refurb injector from the VERY helpful Keith at United Diesel in Shropshire and drove (phut-phut-phut) to Land Ranger in Deeside (The welsh one, not the Scotty one) and paid them to just change the whole bloody lot and give it back to me once it's working again.
• Drive around with mixed emotions:
  • Good times:
    • Car runs great now, no misfire and I swear it's smother than before even the misfire
    • I know the new loom will hopefully prevent future problems even if it wasn't the cause of this specific misfire
    • I now know loads about misfires on TD5s and feel confident in diagnosing any future problems
  • Bad times:
    • Wallet now lighter to the tune of £320
    • I now know loads about misfires on TD5 and my Disco 2 what's-going-to-break-next phobia is now running on DEFCON 3 (previously 4)

Hope this helps.

James

Sorted!!, Changed The Injector Loom And Now 100%