BillB+23 Posted December 31, 2011 Share Posted December 31, 2011 the title says it all really Intermittent rough running Discovery 2 TD5. It started a couple of weeks back and was OK most of the time but sometimes I'd start the car and it felt like it was only running on 4 cylinders, you could can really feel the "misfire" (I realise its a diesel so its not quite like that but that the bet explanation of the feeling) whilst in Drive (its and auto) with stationary with the brake on and pulling way the vibration is quite pronounced although it can also be easily noticed in neutral. This was a rare occurrence for about a week and had to relation to engine temperature. although often if the car was left off for a few minutes it would go back to normal. however the problem is getting worse in that more often than not its running rough. I checked the tinterweb and thought I'd nailed the problem, oil in the ECU wiring they all said, not being adverse to twirling a few spanners I checked it out expecting to find a nice simple problem I could sort out. Both connectors were spotless I disconnected and reconnected just to be sure but both were in perfect condition but the problem remains, the car is drivable but somethings a miss. Ant ideas before I book it into the garage? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted December 31, 2011 Share Posted December 31, 2011 Yes. Change the injector harness anyway - oil or not. They break down in some way with age and heat and give a misfire exactly like you describe - gets worse as the engine gets hot, and gets worse with the passage of time. £40 ish for a new one and from what you say you should be able to change it yourself - it's just a case of popping the rocker cover off and unplugging it. Only 'care point' is make sure the gasket is correctly located where it goes round the back of the cover when you refit, or you'll end up with a mutha of an oil leak. 95% likely that this will sort it and in any case you need to definitely rule it out before spending time on anything else. Dud injector is another possibility though they usually break and stay broken, and injector washers generally cause a non start (or engine stop) as well and you haven't mentioned that. Quote Link to comment Share on other sites More sharing options...
davyd8899 Posted December 31, 2011 Share Posted December 31, 2011 Injector harnees as bog monster said sound the most likely as it happened on my disco. After changing this if you still have a problem, try changing the diesel filter. Also on the TD5 there is a 1 way valve on the pipes going into the diesel filter. I had the same thing on my old TD5, could not find anything at all with it, was going to by pass the filter to see if this made a difference, thats when i found the valves on the pipes. Took the valve out and presto, 1 normal running TD5!! However they do need replacing as diesel then heads back into the tank from the filter, thus creating starting issues if left standing for a period of time Quote Link to comment Share on other sites More sharing options...
bear Posted December 31, 2011 Share Posted December 31, 2011 Fully agree with BogMonster. Had exactly the same on mine (04 TD5). Only occured when got up to temp and even when I checked the continuity of the wiring on the old one is was ok - no apparent breaks in wires Regards & Happy New Year, Griff Quote Link to comment Share on other sites More sharing options...
BillB+23 Posted January 3, 2012 Author Share Posted January 3, 2012 Thanks I'll give the harness a go and report back Quote Link to comment Share on other sites More sharing options...
BillB+23 Posted January 5, 2012 Author Share Posted January 5, 2012 My apologies of this ends up getting posted twice, I'm not familiar with how long it usually takes to authorise posts. Before i do this work and having checked for the wiring looms there are 2, the one that goes to the ECU and the one that is actually located under the rocker cover. I'm pretty sure you mean the one that connects to the ECU, I'd link to Ebay but I'm not sure of that allowed. Can someone confirm which one I should go for first, I appreciate this might not fix it but at about £40 its go to be worth a try given the number of reports of problems in this area. Quote Link to comment Share on other sites More sharing options...
stuck Posted January 5, 2012 Share Posted January 5, 2012 I'd start with the one under the rocker cover as that is subjected to the worst of the heat & vibration. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted January 5, 2012 Share Posted January 5, 2012 Had something very similar on mates TD5. Only started when running for a while and quite fast (thin oil). Turned off engine and restarted and OK for a while then bad again. Continued in similar vein but interval where it ran well got shorter and shorter. Eventually took rocker cover off and ther was oil in all 5 injector connectors. Quick blast with brake cleaner and a dab of Vaseline (why would someone have Vaseline on a laning trip??) and she was back to normal. Has done many miles since and still fine AFAIK..... Quote Link to comment Share on other sites More sharing options...
BillB+23 Posted January 6, 2012 Author Share Posted January 6, 2012 Sounds exactly like the same symptoms as mine, I'll do your fix first (I'm sure I can lay my hand on some Vaseline !!) and if it continues to play up I'll replace the loom. Quote Link to comment Share on other sites More sharing options...
BillB+23 Posted January 8, 2012 Author Share Posted January 8, 2012 Had something very similar on mates TD5. Only started when running for a while and quite fast (thin oil). Turned off engine and restarted and OK for a while then bad again. Continued in similar vein but interval where it ran well got shorter and shorter. Eventually took rocker cover off and ther was oil in all 5 injector connectors. Quick blast with brake cleaner and a dab of Vaseline (why would someone have Vaseline on a laning trip??) and she was back to normal. Has done many miles since and still fine AFAIK..... Did this and just come back from test drive (read irresponsible thrashing round the back lanes ) she runs as smooth a silk now, at least if the problem starts up again I'll know just to get a new loom, there was oil in all the connectors. Thanks so much guys, I'm more used to spinning spanners on 2 wheeled machinery so the help is really appreciated Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted January 8, 2012 Share Posted January 8, 2012 Glad to be of help Quote Link to comment Share on other sites More sharing options...
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