Defendern00b Posted January 28, 2022 Share Posted January 28, 2022 Hey folks, quick question... My starter motor engages as soon as I connect up the battery (even with the ignition off). Any suggestions here? I'm all out of holy water, so an exorcism is off the cards. Next logical step is a post in the forum! Currently I've got the battery disconnected to calm the beast, but as soon as I hook up the terminals the starter turns. If I flick on the ignition then it fires up straight away but the starter keeping turning. Sub optimal to say the least! It's a 90, 1991 200tdi. Appreciate any advice before I climb under there and find out whats going on (its cold, damp and dark out there so would like to be armed with guidance to minimise frostbite!!) Cheers Quote Link to comment Share on other sites More sharing options...
western Posted January 28, 2022 Share Posted January 28, 2022 Sounds like a stuck engaged soleniod or it could be a duff starter relay thats has fused itself in the power on position. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 28, 2022 Share Posted January 28, 2022 16 minutes ago, western said: or it could be a duff starter relay thats has fused itself in the power on position You could pull that relay out easily enough and that would prove or eliminate it as the cause. 1 Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted January 29, 2022 Author Share Posted January 29, 2022 Thanks for the quick replies. Things took a strange turn. I connected the battery and sure enough the starter came alive. Turned the ignition and it fired up, then the starter magically stopped engaging. Brilliant! One of those self fixing issues! Tested a few more starts and all was fine. Lovely. Lock up, head inside and put on the kettle. But then the alarm starts making some really weird noises. Like it's arming/disarming. I pop my head out to see a load of smoke, the stench of melting wires and plastic and a very bad feeling in my tummy. Whip the terminal off the battery, smoke subsides and I change my underwear. I haven't yet checked the damage, but something electrical is very unwell here. I'll follow leads from battery, earth's etc as well as check relay. Any thoughts on the culprit here. It was scary biscuits for a few minutes...expecting an electrical fire to take out the truck and the house with it!! Quote Link to comment Share on other sites More sharing options...
Escape Posted January 29, 2022 Share Posted January 29, 2022 😧 Good thing you caught it before it got any worse! As above, 2 likely suspects, either the starter relay or the solenoid on the starter motor sticking. In both cases current will flow and the starter will keep turning, causing the wires to heat up excessively. I hope the damage isn't too bad... Filip Quote Link to comment Share on other sites More sharing options...
western Posted January 29, 2022 Share Posted January 29, 2022 Hope the damage is limited, good you kept a eye on it while the kettle was on. Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted January 30, 2022 Author Share Posted January 30, 2022 Relay is tested and fine and on a positive note, the starter doesn't engage until ignition is turned now. Less positive, but also seemingly pretty minor is the wiring damage. In cases like this, is it feasible to salvage any of the wiring or will they just need replacing with a less toasty alternative? Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted January 30, 2022 Share Posted January 30, 2022 The first priority has to be to work out why it's gone so crispy if the relay is ok. Clearly all is not well in the solenoid at the very least. I would keep the battery disconnected (as you have been) until the cause is established even if everything now seems fine. Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted January 30, 2022 Author Share Posted January 30, 2022 For sure. Battery will stay disconnected until solenoid and cables are replaced. I'm wondering if the cause was a battery isolator switch that the previous owner installed. Tracing the battery cables from starter, I can see they're melted all around isolator too. I actually bypassed the isolator a few weeks back because the beast was lazy to start. Immediately better once the switch was out of the circuit Quote Link to comment Share on other sites More sharing options...
92a Posted January 30, 2022 Share Posted January 30, 2022 If that’s all that’s been damaged you might be able to get an engine loom from Autosparks , mine did something similar and melted the red and white wire into the main loom above the fuse box, you may have been lucky Quote Link to comment Share on other sites More sharing options...
western Posted January 30, 2022 Share Posted January 30, 2022 Get a new engine loom from Autosparks, ring & talk to them & state what amps your alternator 45/65 or 100. Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted January 30, 2022 Author Share Posted January 30, 2022 Thanks for the advice. Looks like this guy: https://www.autosparks.co.uk/land-rover-defender-90-110-engine-wiring-harness-3 Finally How can I tell the alternator ampage? Quote Link to comment Share on other sites More sharing options...
western Posted January 30, 2022 Share Posted January 30, 2022 Should be a label or metal plate on alternator, normally they were 45amp but 65amp was a option, This is the 65amp Alt engine loom with ring tetminals at alternator https://www.autosparks.co.uk/land-rover-defender-90-110-engine-wiring-harness-4 Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted January 30, 2022 Author Share Posted January 30, 2022 Perfect. That looks more like it. I'll check tomorrow in the light and get the parts ordered up. Are there any tips to make life easier when re-routing the new loom? No doubt it'll need the flexibility of a gymnast to work it through all the tight little gaps. Appreciate the help all. Quote Link to comment Share on other sites More sharing options...
western Posted January 30, 2022 Share Posted January 30, 2022 Its easy to route, just follow tje existing loom. Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted February 1, 2022 Share Posted February 1, 2022 Don't forget that the loom is only the victim of the fault, probably not the cause. You still need to identify and correct that. Mike Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted February 1, 2022 Author Share Posted February 1, 2022 Thanks. I'm pretty confident the isolator switch was the culprit. Since we got the defender it's always been lazy to start, despite a new battery, checking earth straps, confirming alternator is good etc. After the slow start, the battery light would come on at first, until giving it some revs. Then it went out and life was good. When I bypassed the isolator a few weeks back, it fired up immediately. Even on icy mornings. By then I suspect the loom damage was done and we were on borrowed time. Last week was likely a case of the knackered wires finally shorting out and getting crispier than a findus pancake. I've got a new loom ordered up and will change the starter solenoid and isolator too. Then we'll have a defender that fires up like it should at last! Quote Link to comment Share on other sites More sharing options...
Eightpot Posted February 1, 2022 Share Posted February 1, 2022 Last time I dealt with this kind of fault it was down to an overheated and melted solenoid on the starter motor. I suspect that may have been brought on by another fault but it was a few years ago - possibly a faulty ignition switch or wiring short that kept the motor spinning while the engine was running. Incidentaly, the wiring on that solenoid looks awfully close to touching the metalwork on the photo? Quote Link to comment Share on other sites More sharing options...
Defendern00b Posted March 13, 2022 Author Share Posted March 13, 2022 For those that need a little closure, the replacement loom and bypassing the isolator switch has solved the problem a treat. Now the old beast fires up straight away and has cured a problem with battery light staying on after startup that I never was able to shift before. The old loom and positive battery cable were toasted beyond recognition. Looked to be shorting on nearby metalwork too causing all my woes. Thanks all for the advice. 3 Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted March 13, 2022 Share Posted March 13, 2022 Here's a link to a good explanation of starter circuits that I came across recently. It explains the relationship between the starter relay and the starter solenoid. https://startersolenoid.net/starter-relay/ Mike Quote Link to comment Share on other sites More sharing options...
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