DiscoHere Posted July 19, 2012 Share Posted July 19, 2012 Hi all My 2003 TD5 has started missing under load. I have been told it is the loom into the CPU (oiled up). What do you think and how do I fix it? Hugh Quote Link to comment Share on other sites More sharing options...
Julian Posted July 20, 2012 Share Posted July 20, 2012 I'm no expert, but I had this problem on my (late) Disco TD5. It was under warranty, LR4*4 said it was the injector loom and dispatched a mechanic to my house to replace it, (about a 1 hour job) It did not fix it so he drove it away and replaced the electric boost pump in the fuel tank - this did the job. Julian. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted July 20, 2012 Share Posted July 20, 2012 I read the title and saw the answer "Found under bonnet after short search" forming in my mind But on a more serious note, depending on what it sounds like I would also probably start with the injector loom (as it's cheap, and they go wrong anyway so never wasted) and then the fuel pump. The harness tends to cause an increasing miss as it warms up (ok when you start it, take it for a 5 mile run and it will be running on four, let it cool off for a few hours and it will be ok but then do the same again). However once it's missing, it usually does so even at idle no-load. The fuel pump is a pressure loss when on full load so it is usually OK on the flat and at idle but cane it up a steep hill (somewhere you can use full throttle in 3rd / 4th for a sustained period) and it will shake the vehicle with the vibration and power will drop off. The pump basically gets weak but £200 odd for a new pump will fix it. To change it you need to take up the carpet in the boot (not a 5 min job) and there's a plate in the floor which you remove and the pump is underneath. You'll probably need to clean lots of muck off the top of the tank so none falls in. Then there is an electrical connector and IIRC 4 pipes with quick release fixings, and a big plastic ring which according to the book needs a special tool but in practice can be removed with care by working your way around the lugs tapping it with a hammer and some sort of blunt drift (blunt cold chisel or very large flat bladed screwdriver). The connectors are easy to break off and then you need a new fuel pipe - you can get the tools to release these fittings on Ebay I think. Note which order they go (they don't run so good if the pipes get mixed up but I think they are normally colour coded) and then find yourself a BIG container (2 gallon plastic bucket is ideal) and once the pump is free, lift it straight up (getting the float out of the tank will be a fiddle) and slide the bucket underneath as there will be diesel in the swirl pot which will go everywhere in the back of the vehicle otherwise. Refitting is reverse of removal and then you need to bleed it. An 03 will have the auto bleed cycle built in so turn the ignition on, pump the pedal to the floor and back five or six times and one of the lights (engine I think) starts flashing. You'll hear the pump cycle on for about 30 sec, off for 5, on for 30, off for 5 and do this about five times. When it gets to the end of this cycle, depress the throttle to full and crank it till it starts (usually 10-15 sec, all being well). It's not a hard job but can be messy or inconvenient if you break something. Injector loom should be covered in the tech archive somewhere so look in there. The fuel pump might be as well (says he, after writing that lot ) HTH. Quote Link to comment Share on other sites More sharing options...
Julian Posted July 21, 2012 Share Posted July 21, 2012 Hi Bog Monster, you seem to know a lot about this issue. I've always been intrigued as to why the injector harness gives trouble on the TD5, I understand that it's oil working it's way along the wires, but why should that give trouble? - oil is a good insulator and the old electric welder sets used to run immersed in oil! I would go as far to say that oil on wires and connections is a good thing as it keeps the moisture and air out and thus helps prevent corrosion..... Julian. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted July 21, 2012 Share Posted July 21, 2012 I have no idea but all I know from years in the business is that it happens to all of them, whatever the tech bulletins say. Later ones last longer but they still fail. I think it may be an insulation breakdown but really not sure - everything you say makes sense and I never understood the physics I just know it was our first point of call with a misfire of a certain type and 90% likely to be right... Later engines they figured out it was better to put the wiring on the outside and the oil on the inside! Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted July 21, 2012 Share Posted July 21, 2012 One trick we have learnt is that after changing the engine harness is to deliberately destroy the oil seal where the wires leave the engine. Any oil that gets that far will then leak out and not carry on down the wires to the ecu. The harness from the engine to the ecu is expensive and we have never changed one - just cleaned up the oil from the ecu connections. We once had a Defender where the ecu (under the seat) was awash in oil but didn't have to change the ecu or the main harness after a cleanup. Quote Link to comment Share on other sites More sharing options...
simonr Posted July 21, 2012 Share Posted July 21, 2012 Jim, a better solution, which maintains the waterproofing is to clean all the oil out with contact cleaner (petrol, diesel or any other solvent in the field), then fill the plug & socket air spaces with petroleum jelly, so that when you push the plug in to the socket, the jelly extrudes out. This will stop the oil (dirty oil is slightly conductive) from providing an electrical path between the pins. This causes the ECU to mis read sensors etc, which is what causes it to run badly. I used this trick on mine 4 years ago and never had the slightest problem since. Si Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted July 21, 2012 Author Share Posted July 21, 2012 Hi all I got at the ECU and harness this morning with pure Alcohol and a brush......cleaned it all up and dried it with kitchen towel. All works a dream now. I guess I have to go and replace the injector harness now to prevent it happening again . Thanks for the advice Hugh Quote Link to comment Share on other sites More sharing options...
simonr Posted July 21, 2012 Share Posted July 21, 2012 Hugh, Try the petroleum jelly - then don't bother replacing! If you are anxious, keep a can of contact cleaner and a pot of jelly in the glove box. Might be worth telling your wife/GF what they are for before she makes any 'assumptions' !!! Si Quote Link to comment Share on other sites More sharing options...
sierrafery Posted July 21, 2012 Share Posted July 21, 2012 see this http://www.discovery2.co.uk/Injector_harness.html Quote Link to comment Share on other sites More sharing options...
BogMonster Posted July 21, 2012 Share Posted July 21, 2012 Or our own Tech Archive http://forums.lr4x4.com/index.php?showtopic=42788 Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted August 22, 2012 Author Share Posted August 22, 2012 Having read the replies and listened to the advice I decided to renew the Injector loom. I ordered it from Alive Tuning an it was delivered as promised almost immediately. The job took no more than 1 and 1/2 hours from start to finish including clean up, I did take a lot of time trying to get the rocker cover on so maybe there is a trick in that. Anyhow the car is now going much smoother and quicker. Overall it appears to be much more responsive but unfortunately it is still missing intermittently and for no reason. I have driven over 50 miles since I renewed the loom and it appears to go very well for ages then misses a few times. Any suggestions as to what might be causing it ???????????? Hugh Quote Link to comment Share on other sites More sharing options...
fozsug Posted August 22, 2012 Share Posted August 22, 2012 A sticking wastegate on the turbo will cause this, or possible fuel pump on the way out. Maybee The turbo wastegate modulator Unlikely but could be the MAP sensor , give it a clean up. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted August 24, 2012 Share Posted August 24, 2012 You could have an air leak at the filter. Maybe you should get it on a pooter but that doesn't really help for intermittent problems which can be a person I'm not that keen on to find and fix. Try changing the injector copper washers - that has fixed a few misfires and such that I remember. The job is a pain though. ps I didn't write 'a person I'm not that keen on' at all Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 24, 2012 Share Posted August 24, 2012 You didn't. Careful, or you'll get moderated Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted August 25, 2012 Share Posted August 25, 2012 Well, I did replace the 'a' with an '@' Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted August 27, 2012 Author Share Posted August 27, 2012 Right I am putting it on a Computer tomorrow.. I will let you know the outcome (before I sell it) Hugh Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted August 28, 2012 Author Share Posted August 28, 2012 Problem solved ???? I brought my Disco to the independent LR specialist I use and he promptly told me within a minute that the problem was the drivers accelerator not sending the correct signal to the engine. He tested the pump and the injectors along with a few other items. He reset the accelerator sender unit and I now driven about 70 miles with only 2 or 3 hiccups. That tells me he is right in his assessment but unfortunately i will probably have to replace the unit in the near future. Does anyhow know what is involved? How likely is it to cut out fully in the middle of a journey? I have no doubt it will not be simple task and I will probably have to give it to someone with the necessary computer to sort out. Hugh Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted August 28, 2012 Share Posted August 28, 2012 Driver demand problems usually result in the engine going back to idle and refusing to rev up until its been shut down and restarted - so I'm thinking its unlikely to be that.The best way to check that conclusively is to scope the outputs at the ecu connector.Usually one trace will give a dirty output. A sticking wastegate will make the ecu cut fuelling when overboosting,but not cause misfiring - just flat performance and is easy to check for, more than 230Kpa is overboost under full load. Where any faults logged ? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 28, 2012 Share Posted August 28, 2012 I concur with Mr V8 above ^^. DD faults usually lead to an impotent pedal and a warning light on the dash. Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted August 29, 2012 Author Share Posted August 29, 2012 Thank you Bog Monster and Mr V8. I did get such occurances a few weeks ago but put that down to a faulty battery that has since been replaced and apparently resolved the issue. If i do have to change the pedal and sender unit what is involved? Is it as straightforward as taking one out and putting a new one in? Hardly.............. Quote Link to comment Share on other sites More sharing options...
DiscoHere Posted October 1, 2012 Author Share Posted October 1, 2012 Just to update everyone. I replaced my accelerator pedal today and had it re introduced to the ECU (computer dating is alive and well). I have driven it for a over 100 miles and not even a hesitation. Hopefully all sorted now. BTW I confirmed the problem in my own mind by driving with cruise control engaged.....no problems but they reoccurred the minute I disengaged it Thanks for all the suggestions Hugh Now to sort the heated seat............. Quote Link to comment Share on other sites More sharing options...
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