skishop69 Posted August 11, 2017 Share Posted August 11, 2017 Loaded voltage drop tests do not apply to circuits that have a dead short. Only to circuits that may not be supplying the correct amount of power to their respective components due to wiring or terminal issues. You need to test for a short to ground just as Scott described. Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 But the fuse does not blow with the ign relay removed, correct? Even with the key on? Quote Link to comment Share on other sites More sharing options...
skishop69 Posted August 11, 2017 Share Posted August 11, 2017 Put a new fuse in. Find which large gauge wire at the relay has 12v on it with the key off. The other large gauge wire will have no voltage on it with the key off. This is the power out of the relay. Test THAT wire to ground with the meter and see what the resistance is. Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 (edited) OK, I found a part of a basic schematic. The fuse that is blowing is number 11, a 15 amp? If so, disconnect the ignition coil and condenser and try it. Edited August 11, 2017 by Subaru Scott Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 White/black ignition relay wire shows 750 ohms Fuse 11 is 11.8 volts when battery is 12.2 or 12.4 Fuse 11 blows every time like this: turn key, there's always a delay of like 2 seconds then the ignition relay clicks and the fuse blows instantaneously. Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 OK, if the fuse does not blow with the ign relay removed, it looks like something funny is going on with the ECU. Is the fusible link still good? Quote Link to comment Share on other sites More sharing options...
skishop69 Posted August 11, 2017 Share Posted August 11, 2017 +1 However... You could have a dead short in the relay windings. Rare, but I've seen it. Either way, the relay, ECU or the circuit to the ECU is shorted to ground. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 (edited) Thanks guys - you got it. It was the igniter or its wiring....I'll check that tomorrow. The fuse that is blowing is number 11, a 15 amp? If so, disconnect the ignition coil and condenser and try it. Yes fuse 11 15 amps. disconnecting the igniter (is that the same as condenser?) and the fuse doesn't blow any more. Woo hoo! So now I have to figure out if it's the wiring or condensor itself. Probably the condensor? I've got a bunch I can just sacfrifice one to test. But the fuse does not blow with the ign relay removed, correct? Even with the key on?I went and checked before I did the coil/igniter. The fuse does blow with the relay removed. I was using a larger complete schematic that was just the smallest one I could take a picture of. Edited August 11, 2017 by idosubaru Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 +1 However... You could have a dead short in the relay windings. Rare, but I've seen it. Either way, the relay, ECU or the circuit to the ECU is shorted to ground. We got it - it was the igniter on the coil bracket. I guess i never said or maybe tested it incorrectly, what happened with the relay removed. or maybe I accidentally tested that with the igniter disconnected? Also that schematic I posted isn't good - it's incomplete and doesn't show that entire circuit for some reason, I only posted it to show the relay as the main schematic is two page fold out and hard to follow. Thanks for the guidance. You would have figured this out in like 11 minutes haha. Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 Awww man... I was just getting fired up for the hunt of something really crazy going on there Like I said, electrical is my favorite, and especially diagnosing problems. Just a lot harder to do without the car in front of you... Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 Thanks again guys. Huge help. I'll finish tomorrow but I think the wiring for this igniter has wires spliced into it for a large box that is for the Hella headlights. Like you said - look for the wiring work! Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 They tapped power for the driving lights off the ign coil?!? That would be the problem. Cut that loose from there and I bet it runs fine. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 Good news/bad news - new coil and igniter and it runs fine. black fusible link smokes and within seconds it's burning skin but didn't blow. Swapped another and same thing. Never blew and car idle fine for a minute or two. When this whole incident started it blew a fusible link. My plan: See if it does it only when running or also just ignition ON. Then pull all the cabin fuses and see if it still does it and introduce one at a time. Can I use my multimeter? My meter fuse is only 10amps so I imagine I'll blow that if I try to measure amps for testing this "draw" like I would a battery drain? So Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 They tapped power for the driving lights off the ign coil?!? im not sure what it is now but not lights. It's a large box by the lights, an aftermarket ignition box? installed a stock coil and bracket and wiring and disconnected that box (I think it's all gone) Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 Are there any other wires going to the mystery box? Search out any non-stock wiring and focus on that! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 Thank you all very much. Alternator is putting out 16+ volts. Does that mean the voltage regulator failed? So I guess it failed, blew out two fuses, a fusible link and the igniter? Appreciate it guys! I learned some about testing that'll help next time. Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 11, 2017 Share Posted August 11, 2017 Yup, 16 volts too high. Better check all your light bulbs too! Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 11, 2017 Share Posted August 11, 2017 Yup, 16 volts too high. Better check all your light bulbs too! yeah that would explain the hot and smokin black fusible link. that's the one ALT charge goes through. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 11, 2017 Author Share Posted August 11, 2017 Copy thanks, will do. The transmission is only staying in first gear. It runs and drives and i drove it to my office, but I can only manage this for a short period. Also the blinkers don't work and the blinkers and AT control unit share the same fuse - so I'll be tracing that tonight. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 14, 2017 Author Share Posted August 14, 2017 (edited) Yup, 16 volts too high. Better check all your light bulbs too! Good call, the blinkers aren't working, but they were before this incident - but how did they blow if no lights were on when this happened? I guess maybe it overcharged previously when I did use the blinkers? There are three bulbs not working up front and two are buried under the fender with no easy access. The transmission is only staying in first gear. It runs and drives and i drove it to my office, but I can only manage this for a short period. I swapped the transmission computer and it shifts perfect - why didn't the fuse blow before damaging the TCU? Edited August 14, 2017 by idosubaru Quote Link to comment Share on other sites More sharing options...
Subaru Scott Posted August 14, 2017 Share Posted August 14, 2017 Fuses and circuit breakers are kind of funny when it comes to an overvoltage incident. They only blow/trip when the amperage is too high. I worked in a bike shop in the 80s and when a regulator would fail, sending the voltage to 16-17 volts, it would wipe out every bulb on the bike but never blow a fuse. Same thing in your house when there is a voltage spike, the breakers will not trip. Only when amperage, or amount of current is exceeded. Now, when your regulator failed, it just went full field, so volts and amps were unregulated. If a device or component will USE more amps than the fuse can handle, it will blow. A battery will take all the amps you can throw at it, which is why your black fusible link was smoking. Other devices will not use all the amps the system is rated at, unless they have a failure. Your TCU uses hardly any amps, so no chance of blowing the fuse. Obviously, it couldn't take the voltage, which is a shame but at least you had a spare. A testament to how tough Subaru ECUs are! Was that an aftermarket alternator? Glad you got her going again! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 14, 2017 Author Share Posted August 14, 2017 Got it - bulbs are rather fragile Was that an aftermarket alternator? I think so, it's very clean and appear newish. I think there's a mitsubishi logo on it, i think they're sometimes an OEM supplier? I'm not sure I have another spare alternator - though I'm pretty sure I've got on somewhere, but I'll need another option at some point. I know nothing about the one on there now. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 14, 2017 Author Share Posted August 14, 2017 at least i figured out the alternator and TCU on my own, after all that hand holding you poor souls had to do in the beginning. ha ha thanks Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 14, 2017 Share Posted August 14, 2017 There are three bulbs not working up front and two are buried under the fender with no easy access. If you are talking about the front corner markers in each fender, they are easy to pop out for bulb changing. slip a thin flathead screwdriver into the center of the space at the front between the bumper. there is a tab that if pressed down back will alloy the front of the lens to slip out, then pull the whole thing forward to slip the rear tab out of the fender. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 14, 2017 Author Share Posted August 14, 2017 If you are talking about the front corner markers in each fender, they are easy to pop out for bulb changing. slip a thin flathead screwdriver into the center of the space at the front between the bumper. there is a tab that if pressed down back will alloy the front of the lens to slip out, then pull the whole thing forward to slip the rear tab out of the fender. Yes I am. Wow, thanks a ton Gloyale I was dreading that. I'll practice on parts car/stash first. It's been 10 years since I think i've removed one. Quote Link to comment Share on other sites More sharing options...
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