evanmc Posted October 22, 2019 Share Posted October 22, 2019 1985 110 2.5NA Most unfortunate -- when I started my vehicle yesterday, the passenger compartment filled with smoke, and when I could get to the engine bay, I found the engine harness on fire. Aside from the fact that this is a not-so-subtle reminder that I should keep a fire extinguisher on board, my question here is possible causes. But first, some background. This harness is only a year old -- I purchased one from autosparks in 2018 to replace my last one that caught on fire (yes, this has happened before). In that instance, my alternator had fouled to the point that was the source of the problem (I believe), so I had that one rebuilt, replaced the wiring harness, and all was well for a year. Seems like there are two possibilities for this last burning: the harness shorted out against the block (a crack in the insulation? I certainly can't tell anything now that it has burned up) or the alternator is fouled again. Is my thinking wrong here? Is there a way for me to test the alternator to see if it is OK, or do I need to remove it and take it to my local alternator shop? I purchased this harness -- I did have to replace the loops on the alternator end with female connectors to fit my alternator, but I assume that was the correct one otherwise. https://www.autosparks.co.uk/lr423-land-rover-defender-90-110-engine-wiring-harness.html -Evan- Quote Link to comment Share on other sites More sharing options...
western Posted October 22, 2019 Share Posted October 22, 2019 What amp output was the alternator? That loom you linked to is for a 45amp alternator, with a option to upgrade to 65amp. Quote Link to comment Share on other sites More sharing options...
evanmc Posted October 22, 2019 Author Share Posted October 22, 2019 I'll need to check. Don't know off the top of my head, and perhaps that is my problem -- if I bought too small of a harness for my alternator output. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 22, 2019 Share Posted October 22, 2019 LR don't fuse the main feed (brown wires), that's what nearly got Nige's 90 where the loom chafed behind the dash. I'd have to re-glance at the wiring diagram but there's certainly scope for a midi-fuse or two in the system to remove some of the risk. Quote Link to comment Share on other sites More sharing options...
evanmc Posted October 22, 2019 Author Share Posted October 22, 2019 Good suggestion -- i can certainly put some fuses in (where along the harness?) And here's where I have a somewhat dumb question -- if I want to get things running again fairly quickly, can I just run some (reasonably large) wires between the starter and alternator? The remaining wires on the harness look undamaged (I believe the harness also has wires to the starter and fuel solenoids?) I'll replace the whole thing, but the timing here is bad in that I need to get it registered before the end of the month. -Evan- Quote Link to comment Share on other sites More sharing options...
monkie Posted October 23, 2019 Share Posted October 23, 2019 Did this happen when you held the glow plugs on? It is easy to not spot a possible short to the engine on the glow plug feed wire. When you tightened the terminal screws on the glow plugs one of the terminals could have rotated slightly to make contact with the head. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 23, 2019 Share Posted October 23, 2019 14 hours ago, evanmc said: Good suggestion -- i can certainly put some fuses in (where along the harness?) And here's where I have a somewhat dumb question -- if I want to get things running again fairly quickly, can I just run some (reasonably large) wires between the starter and alternator? The remaining wires on the harness look undamaged (I believe the harness also has wires to the starter and fuel solenoids?) I'll replace the whole thing, but the timing here is bad in that I need to get it registered before the end of the month. -Evan- I can't recall the exact routing but between the starter and the two or three large brown wires which go into the dash (and power everything from there) is a good spot for a moderately sized midi fuse - I used 2x 20A blades (one per brown wire) on the ambulance because I had the space in an extra fusebox; If the only burnt wire is the alternator one then just replacing it with one that's at least as big as the old one (bigger won't hurt) should get you going - just be aware you need the warning lamp wire (brown/yellow) to excite the alternator so if that's damaged you need to replace that too. Quote Link to comment Share on other sites More sharing options...
smallfry Posted October 23, 2019 Share Posted October 23, 2019 I thought the alternator output went direct to the starter solenoid, and the main vehicle live feeds came from the same solenoid terminal ? Long time since I have seen one though. I would be inclined to take the vehicle live feeds direct from the battery and put some fuses in. A thought though, do you have a rodent problem ? Quote Link to comment Share on other sites More sharing options...
evanmc Posted October 24, 2019 Author Share Posted October 24, 2019 Yes, the power feed from the alternator goes to the starter solenoid, and the main feeds for the vehicle are on the same terminal. I just took a look at the chard remains. It looks as if I did route two large wires from my alternator to the starter instead of using the wires in the harness. It was one of these wires that caught on fire, burning all the way from alternator to starter. In the fire, the glow plug wire insulation was burned off at one of the cylinders. so that looks like it was collateral damage, not the cause. The only alternator wire in the harness I am using is the one leading to the third terminal on the alternator (I am assuming that is for the warning light) I did find that around the starter there was substantial amounts of oil covering everything -- including the starter solenoid. Yes, we do have rats, but I haven't seen any evidence of them. Certainly a possibility -Evan- Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 24, 2019 Share Posted October 24, 2019 Also be mindful of the dash lighting too... that is un-fused... ask me how I know this. Mav Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 24, 2019 Share Posted October 24, 2019 2 hours ago, Maverik said: Also be mindful of the dash lighting too... that is un-fused... ask me how I know this. Yep, the whole Series lighting circuit is un-fused... because glass fuses start to smoke at around 15A. You can whack a blade fuse in there somewhere and it will at least keep the overall lot from catching on fire if there's a short, although it's not as nice as putting properly rated fuses in each circuit. Quote Link to comment Share on other sites More sharing options...
Arjan Posted October 24, 2019 Share Posted October 24, 2019 Quite normal for Series to have all (as in : 2or3) glass fuses out and to find everything works... There is a reason why I make my own looms..... Quote Link to comment Share on other sites More sharing options...
Waldorf Posted October 24, 2019 Share Posted October 24, 2019 I like the idea of using garden hose for that! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 24, 2019 Share Posted October 24, 2019 21 minutes ago, Waldorf said: I like the idea of using garden hose for that! Old coolant or hydraulic hose can be tough as hell for protecting wires where they run near sharp things or risk rubbing... but it's a bit cumbersome for the majority of the loom. I'd be concerned about the fact all the fuses are 20A, suggests there may be some slightly under-protected circuits there. Still better than 99% of wiring done by LR owners though, neat and tidy and fused! Quote Link to comment Share on other sites More sharing options...
toenden Posted October 24, 2019 Share Posted October 24, 2019 11 hours ago, Maverik said: Also be mindful of the dash lighting too... that is un-fused... ask me how I know this. Mav And the great ting about said dash light is, that it actually origins from the UNPROTECTED side of the fusebox, for some great reason... ask me how I know aswell... /Mads Quote Link to comment Share on other sites More sharing options...
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