dave t Posted December 10, 2008 Share Posted December 10, 2008 Hi Guys just like to say hello I just joined. I have a 1996 discovery 300 tdi which I just bought and it has a small problem with the glow plugs. The light on the dash lights for an instant and then goes out, I have changed the relay timer but its still the same. can anyone help please? Dave Quote Link to comment Share on other sites More sharing options...
BogMonster Posted December 10, 2008 Share Posted December 10, 2008 Put a voltmeter on the terminal of one of the glow plugs and get somebody to switch the ignition on - how long do you have 12V at the plugs for? Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted December 10, 2008 Share Posted December 10, 2008 Unless you are living in -15 degrees, the glowplugs on a TDi are mostly superfluous. I don't think mine are even plugged in. If you are not having problems starting, then I wouldn't worry too much. If you are having problems starting, then I'd suggest you look for another fault (timing maybe) Oh, and welcome to the forum - excellent choice of vehicle. Quote Link to comment Share on other sites More sharing options...
dave t Posted December 10, 2008 Author Share Posted December 10, 2008 Put a voltmeter on the terminal of one of the glow plugs and get somebody to switch the ignition on - how long do you have 12V at the plugs for? the voltage lasts the same time as the light, about half a second, just enough time to register on the voltmeter. I also noticed that very ocasionally the light will stay on for the normal time but only when the engine is warm thanks Dave Quote Link to comment Share on other sites More sharing options...
dave t Posted December 10, 2008 Author Share Posted December 10, 2008 Unless you are living in -15 degrees, the glowplugs on a TDi are mostly superfluous. I don't think mine are even plugged in.If you are not having problems starting, then I wouldn't worry too much. If you are having problems starting, then I'd suggest you look for another fault (timing maybe) Oh, and welcome to the forum - excellent choice of vehicle. it starts ok when its warm, hardly get time to turn the key and its running but when its cold firswt thing in the morning I have to crank it for 15- 30 second before fires. is this normal? The car has done 150k but have a full and complete service history and it runs and drives like its only done 50k thanks Dave Quote Link to comment Share on other sites More sharing options...
s11aun Posted December 10, 2008 Share Posted December 10, 2008 sounds to me like a faulty relay even though you have fitted a new one as the relay is the only thing that has the timer to keep the glow plug power there. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted December 10, 2008 Share Posted December 10, 2008 the voltage lasts the same time as the light, about half a second, just enough time to register on the voltmeter. I also noticed that very ocasionally the light will stay on for the normal time but only when the engine is warm That's a little interesting. I don't have a wiring diagram to hand, when I do, I'll look. A TDi in good nick should fire up right away from cold without plugs. Given that yours has done 150k there may be a number of things that aren't quite so perfect - probably cheapest to get the glow plugs going. Where are you in the country? Quote Link to comment Share on other sites More sharing options...
dave t Posted December 10, 2008 Author Share Posted December 10, 2008 That's a little interesting. I don't have a wiring diagram to hand, when I do, I'll look.A TDi in good nick should fire up right away from cold without plugs. Given that yours has done 150k there may be a number of things that aren't quite so perfect - probably cheapest to get the glow plugs going. Where are you in the country? I will try another relay could be just a bad coincidence that I picked up a faulty one I am just north of Lydney on the A48 to gloucester thanks for your help guys Dave Quote Link to comment Share on other sites More sharing options...
BogMonster Posted December 11, 2008 Share Posted December 11, 2008 I agree - check the relay and also the power/earth feeds to it as it takes about 100 amps so if something is not right it might affect proper operation Quote Link to comment Share on other sites More sharing options...
orangemach5 Posted December 11, 2008 Share Posted December 11, 2008 With regards to starting without glow plugs, we have had a 200tdi and 2 300tdi's (currently still have 1) and both start (ed) first flick of the key in the morning with no heat! Quote Link to comment Share on other sites More sharing options...
trailerfitter Posted December 12, 2008 Share Posted December 12, 2008 With regards to starting without glow plugs, we have had a 200tdi and 2 300tdi's (currently still have 1) and both start (ed) first flick of the key in the morning with no heat! My 200 tdi cracks into life fairly the same way, very simple affair not much wiring,... ..as for the 300tdi the timer relay isn't the only thing in the line with the heater plugs doen't it have a temp sensor on top of the cylinder head, under the rubber sound proofing and controls the time the relay is working for? How you considered taking out the glow plugs and checking each one in turn? Quote Link to comment Share on other sites More sharing options...
dave t Posted December 16, 2008 Author Share Posted December 16, 2008 My 200 tdi cracks into life fairly the same way, very simple affair not much wiring,.....as for the 300tdi the timer relay isn't the only thing in the line with the heater plugs doen't it have a temp sensor on top of the cylinder head, under the rubber sound proofing and controls the time the relay is working for? How you considered taking out the glow plugs and checking each one in turn? Ah temp sensor I didnt know that, I bet thats what it is. I have checked the glow plugs and they are all working thanks for that Dave Quote Link to comment Share on other sites More sharing options...
dave t Posted December 16, 2008 Author Share Posted December 16, 2008 Thanks Trailerfitter you were bang on with the temp sensor, was a dirty connection! cheers Dave Quote Link to comment Share on other sites More sharing options...
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