SLROC Forum

Hello,

  my Defender Td5 wouldn't start tonight - it turned over fine and was on the very edge of "catching", but just wouldn't fire...

  A mechanic came to have a prod and a poke and showed me how to prime the fuel system (you press the accelerator 5 times...I never knew that!) and, on the third or forth go at priming it and turning it over, it fired.  The mechanic reckoned it could be leaking injector seals letting air into the system - I recently had the fuel-pressure-return valve replaced after it started leaking all over the road, so it wasn't that...

  Having done a bit of reading, it seems this is a fairly common problem, but people also talk about the "harness" and the air-flow-valve at the same time...so, I was wondering what this problem was most likely to be, what the symptoms of a dodgy air-flow-valve are, what the "harness" is full stop (I see now people mean the wiring harness - mine's oily, but nothing excessive) and what I should start throwing money at to try and fix my poor old Defender?

  Other things I've noticed recently that might be related (or might not) are it's quite hesitant pulling away from junctions unless I really slip the clutch and rev it and my temperature gauge randomly flicks from about nothing to just under a quarter most of the time...  I've not noticed any changes in the oil or coolant levels at all...

  Any thoughts will be very gratefully received

Thanks,

Paul

Hi Paul,

I believe that the ECU wiring loom should have no oil on it at all, even slighlty oily means that its leaking down the loom, this can cause some of the cylinders to misfire, meaning, difficulty in starting, less power especially when your just pulling of or when the engine is under load as not all the cylinders are firing to turn the flywheel, Its pretty easy to replace the loom and it may solve the problem, plus if its leaking some oil now it will generally just get worse over time, just a thought.

I think replacement looms are between ?50 - ?80 quid, plus maybe a new rocker cover gasket as well for a few quid.

Hope this helps,

John

Paul, TD5 injectors are buried inside the cylinder head,the diesel is fed through a gallery inside the head to surround each injector with fuel,I would say there is no chance of air leaking into the system due to the pump pressure,the most common fault is diesel leaking past the o ring seal on the injector and then into the sump causing the oil level to rise. This would not prevent the engine starting but if oil has travelled up the injector wiring harness all the way back to the ECU  that is more likely to cause problems. Check the ECU plugs under the drivers seat,clean out any oil found with a solvent spray and allow to dry.

Thanks for your help, chaps.

I thought a bit of oil was acceptable, but I'll do as you say, clean the plug to the ECU and see if that improves things...

Thanks,

Paul

Hi,

You should also clean the connector where the loom comes out of the rocker cover (under the plastic engine cover), this has caused me the same problems in the past.

cheers,

 

Hello,

  right, thanks for that - I'll have a go at that one too, then.

  Having now taken the connectors out of my ECU, I've found one (the red one) pretty much swimming in oil, but the other one fine.  I've got my ECU out, sitting on its end on some newspaper to see if any oil comes out of it, but none has so far...

  I've liberally sprayed everything with contact cleaner, so once it's dry, I'll put it back together and see what happens...

  Thanks for your help,

Paul

Hello,

  well, after leaving it to sit for a week on my drive, I got round to fixing my Defender today.

  Having cleaned out the ECU connector and having left the ECU to stand on its end in case any oil had got into it, I decided none had, so just stuck it back in.  I did fit a new injector harness (and rocker cover seal), which turned out to be for the best, as the old harness connector had clearly given up blocking any oil at all...



  Now, here's a "funny" thing (not the sort you laugh at...) - when I fitted the new harness, the plug-end wouldn't fit into the head-casting.  When I compared the new harness with the old one (presumably the original, so fitted by LR themselves), the plastic of the connected had been cut away slightly (I could see the knife-marks!) to make it fit.  So, add to the list of tools required for this job 1x Fretsaw...



  Plug modified, it fitted fine, the rocker-cover-seal is pretty easy to fit too, the cover went on with no drama, so I went on to fit an EGR bypass kit in case that was causing the refusal to start...fitting that was a bit of a drama due to rusted in bolts, but I fitted it in the end and, remarkably, the engine started first time with no spraying of oil, grinding of valve-gear, leaking of exhaust fumes or any of that...I was actually quite surprised!

  I can't feel any difference at all in the performance with the EGR bypass in place, but it does seem to idle smoother...although that could be due to the gallon or so of oil (well, it looked like that much) I extracted from the ECU wiring...hopefully it'll start as happily again tomorrow

  Cheerio,

Paul - waiting for the next thing to fix...