smo Posted March 18, 2008 Share Posted March 18, 2008 My TD5 (D-Lander) is refusing to start, it was working, and now it doesnt. In the process of trying to find the problem (which i may or may not have) i discovered the chassis is earthed as you would expect but the Engine, Gearbox and T-Box are LIVE! The problem is isolated when i unplug one of the multi-plugs on the loom, it appears to feed the O/S of the engine, possibly the injector harness??? Does anyone have any ideas as to what to do, this may or may not be why she wont start when she used to! Quote Link to comment Share on other sites More sharing options...
malpasman Posted March 18, 2008 Share Posted March 18, 2008 Hi, Will the engine crank over on the starter motor? If not, check that the engine to chassis or engine to battery earth is in place, is clean and tight. Alan Quote Link to comment Share on other sites More sharing options...
smo Posted March 18, 2008 Author Share Posted March 18, 2008 It used to.....until yesterday!! The battery earth is fine, as are most others - there is no engine - chassis earth, never was (as of yet! but it used to run like this) and i dont really want to add one whilst one is earth, and the other is live introducing a direct short! Quote Link to comment Share on other sites More sharing options...
malpasman Posted March 18, 2008 Share Posted March 18, 2008 Hi, It sounds like the engine to chassis or engine to battery earth has become disconnected. You need a sound earth on the engine to chassis to battery for the starter motor current to return to the battery. It sounds like this has become disconnected. The reason that the engine appears to be live is that it is rubber mounted, the current has to complete a circuit. If you put a voltmeter on the engine and on the body, you should have zero volts. If you have a voltage reading, the voltmeter is bridging the fault i.e. no earth. What work has been carried out since the fault occured? Alan Quote Link to comment Share on other sites More sharing options...
smo Posted March 18, 2008 Author Share Posted March 18, 2008 Hi Alan, It hasnt become disconnected, there never was one - i built the car from scratch, its never had one and its been running a fair bit recently so clearly didnt need one!! Surely with a live engine and a earth chassis if i connect them i get a direct short - the engine shouldnt be live??? Between the engine running and then failing - the ecu has been moved which involved 2 holes and disconnect/reconnect. Since it failed all batteries, earths, lives, feeds, fuses, relays, switches, plugs and connections have been checked and rechecked. Quote Link to comment Share on other sites More sharing options...
malpasman Posted March 18, 2008 Share Posted March 18, 2008 OK We still need to establish if there is continiuity with the earth between the engine and chassis. Have you got a multimeter? If so, put it on ohms and place one lead on the engine and the other on the chassis, we are looking for a low resistance 1 or 2 ohms, if highter than this, there is a problem with the continuity. We need to establish this, before we can go any further. Alan Quote Link to comment Share on other sites More sharing options...
smo Posted March 18, 2008 Author Share Posted March 18, 2008 Ok - will do that, thanks Alan Just put a meter on it - nothing 0 ohms Quote Link to comment Share on other sites More sharing options...
malpasman Posted March 18, 2008 Share Posted March 18, 2008 Hi, I will have to start my 12 hour lambing shift soon, so will be away from the computer untill mid morning tomorrow. I have known throttle, choke, and heater cables to act as an earth between the engine and chassis before now. I have seen smoking throttle cables with the starter motor struggling to turn over the engine. Is it possible that the return current has been using another path as above, but this now has been disturbed? Will have a think about the problem overnight and get back to you tomorrow. Alan Quote Link to comment Share on other sites More sharing options...
western Posted March 18, 2008 Share Posted March 18, 2008 & the park brake cable can act as a earth path too. Quote Link to comment Share on other sites More sharing options...
Porny Posted March 18, 2008 Share Posted March 18, 2008 The problem is isolated when i unplug one of the multi-plugs on the loom, it appears to feed the O/S of the engine, possibly the injector harness??? Does anyone have any ideas as to what to do, this may or may not be why she wont start when she used to! What colour is the plug, and the wires into it?? Sounds like you got a chaffed cable somewhere, or lacking in earths. Also check for a good earth at the ECU - the pins into the ECU and in the blue bus bar type thing - that has ignition live one side, and earth the other. Ian Quote Link to comment Share on other sites More sharing options...
smo Posted March 18, 2008 Author Share Posted March 18, 2008 Alan - thanks for your help, good luck with the lambing overnight! Alan/Western - it doesn't have heater cables, choke cable, transmission brake cable or throttle (that's fly-by-wire) so cant be any of those. I dont think anything has been disturbed, it ran saturday, we went out for lunch - it rained so i didnt touch it in the afternoon, was out marshalling sunday and monday i moved the ecu and it stopped working!!! Quote Link to comment Share on other sites More sharing options...
smo Posted March 18, 2008 Author Share Posted March 18, 2008 What colour is the plug, and the wires into it??Sounds like you got a chaffed cable somewhere, or lacking in earths. Also check for a good earth at the ECU - the pins into the ECU and in the blue bus bar type thing - that has ignition live one side, and earth the other. Ian The plug is grey - its at the back of the engine and feeds the injector rail/starter/alternator side, i will check the wire colours in the morning as i have to remove panels/covers to see and its dark and cold and late!!! The ECU is earthed via a black wire with a ring terminal coming from the loom next to it, i dont have a blue bus bar (do i)??? I could well be lacking in earths, as i only have the main battery to chassis and some local ones that terminate stuff, but no major block to chassis type earths. Its still doing the same symptoms of turn ignition fuel pump comes on but turn to crank and nothing happens... Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted March 19, 2008 Share Posted March 19, 2008 You can't beat having as many earth cables as possible. Way back when, my Defender scared me to death when the temp gauge went into the red. I eventually twigged it was something to do with the lights being on. I earthed the engine to the bulkhead, and most of the problem went away. The temp and fuel gauges still rise a little bit with the lights on, but at least I know what the cause is now! ps. That problem was traced with help from fellow forumeers - I found that it is a common Defender trait. Quote Link to comment Share on other sites More sharing options...
SteveG Posted March 19, 2008 Share Posted March 19, 2008 Simon, yes you really need to get all the earths sorted out. The TD5 ECU is very temperamental with poor earth connections as it needs a good reference point for sensor readings etc. Have a look in the electrical diagrams and make sure that every ECU earth point is connected. Cheers Steve Quote Link to comment Share on other sites More sharing options...
malpasman Posted March 19, 2008 Share Posted March 19, 2008 Hi, I take it the fuel pump is mounted in the tank or at the back, if so the current for the fuel pump is returning via the chassis earth. Why is the engine appear to be alive? The best way to explain this is to carry out a small experiment, using a battery, 12 volt lead lamp and a multimeter. Connect one lead of the lead lamp to the pos terminal on the battery. Connect the other lead of the lead lamp to the pos terminal of the multimeter. Select a range to display 12 volts dc on the multimeter. Connect the neg lead of the multimeter to the neg terminal of the battery. The multimeter should read 12 volts but the lead light will not be lit. Connect the lead light terminal with the multimeter connected, to the neg terminal of the battery. You should see the 12 volts reading collapse and the lead light should be lit. How will this help us? If we substitute the engine for the bulb and without an earth connected the engine is reading 12 volts. If we connected an earth to the engine, the voltage would collapse and the circuit made. This is a difficult fault to explain without being able to demonstrate all the parameters, I hope it makes some sense to you. OK I am off to bed for a few hours will be on line later. Alan Quote Link to comment Share on other sites More sharing options...
smo Posted March 19, 2008 Author Share Posted March 19, 2008 Ok - Good news, and bad news! Fitted a couple of FAT earth leads (thanks Matt) and now the engine will turn over, bad news is the fuel pump refuses to work anymore! Quote Link to comment Share on other sites More sharing options...
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