rdw Posted August 10, 2009 Share Posted August 10, 2009 Hi everyone, My 2003 TD5 diesel auto was recently given a 72k service by a non-LR specialist. Not long after - approximately 60 miles or so - the engine developed a misfire. It was not immediately apparent at the time. The car starts on the turn of the key and runs fine, but after around 2-3 miles the misfire starts. It feels as though it is not firing on one of the cylinders and consequently at certain speeds 55/60 MPH causes a tremendous vibration throught the car. If it is left for acouple of hours, the cycle starts again i.e runs fine for 2-3 miles, then continously misfires. My wife took the vehicle back to the garage, typically it was running ok at the time- but a new fuel filter was fitted. This did not cure the problem and so it went back again. The mechanic plugged it in to his diagnostic machine and no fault codes were present. He doesn't know. To this end, he has booked the car in to a diesel specialists this week for a diagnostic check on their systems. After reserching this forum, I have checked the wiring harness to the ECU and this is dry and clear of any oil residue. I am wondering, is the misfire, the car actually going in to limp mode for someother reason ? Are there any issues with non OE fuel filters ? Any help would be greatly appreciated Regards RDW Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 11, 2009 Share Posted August 11, 2009 Change the injector harness (the bit that runs inside the head - from the plug on the head to the 5 x injector connectors), the engine running OK from cold and then a progressively worse misfire as it warms up are classic symptoms and not necessarily due to visible oil ingress - I think the insulation on the wiring breaks down or something, not really sure but a new harness will almost certainly fix it. The problem doesn't trigger fault codes in the ECU it just runs like a bag of bolts especially caning it up a hill but when fully warm it will sound like it is running on 4 cylinders even at idle. Les Henson has a good post in the tech archive on changing the harness see here http://forums.lr4x4.com/index.php?showtopic=42788 Quote Link to comment Share on other sites More sharing options...
saltyoldseadog Posted August 11, 2009 Share Posted August 11, 2009 Ah, the wonders of modern technology! A friend of mine had all manner of problems with his new TD5. The computer said the engine was fine but he, the driver knew it wasn't and it took him a long time to find someone - NOT the main agent - who could interpret the computer information properly and use it to diagnose and fix the fault(s). "Computer says NO," isn't always the answer! My own solution to this, as something of a technophobe, is to run a 200 TDi. It's very reliable and simple enough for my chap to fix it when something goes wrong. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 11, 2009 Share Posted August 11, 2009 I think many people believe that the computer is a "silver bullet" which you plug in and it will always tell you what is wrong regardless of whether it is an engine fault or a puncture. Sadly (for those of us that have to take the flak) it isn't like that at all in the real world and while a computer is often essential for modern diagnostics, the hot squidgy connection between the keyboard and the floor is just as important! Quote Link to comment Share on other sites More sharing options...
andyb Posted August 11, 2009 Share Posted August 11, 2009 the hot squidgy connection between the keyboard and the floor is just as important! In IT Tech Support circles this is PEBKAC (Problem Exists Between Keyboard And Chair) Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 11, 2009 Share Posted August 11, 2009 We refer to it here as a vehicle having a bad connection between the seat and the steering wheel but much the same logic Quote Link to comment Share on other sites More sharing options...
rdw Posted August 11, 2009 Author Share Posted August 11, 2009 Yes ! Purchased the injector harness - Bearmach, Maidstone £40 + VAT and fitted it this afternoon. Hey-presto - no misfire ! A massive thank you BogMonster and also Les Henson for the great 'how to' guide. Just as a note, although I had previously checked the harness to the ECU and found this to be clear, when I disconnected the harness at the injector end and let the connector hang down, I was suprised at how much oil dripped from the wiring sleeve ! Clearly the seals had failed. I think the wiring harness to the ECU will be my next job. Thanks again RDW Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 11, 2009 Share Posted August 11, 2009 Forget the wiring harness to the ECU it is never normally needed - just clean out the plugs either end (the red one at the ECU and the one that goes into the head) every week or two until oil stops coming out and it should be OK. I use electrical contact cleaner, others use brake or carb cleaner but any of them are basically just a Foff powerful solvent that will get rid of the oil. The injector harness is usually the first port of call on any Td5 running like a POS, whatever the official tech bulletin says about VIN ranges the truth is that ANY Td5 can and will suffer from the problem and it always causes a misfire. Glad you got it fixed and very happy to help Quote Link to comment Share on other sites More sharing options...
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