docc Posted March 16, 2020 Posted March 16, 2020 Pretty sure it is not that the ECU had such a high ground demand, but that major ground demands (starter!!) were not being met and found their way back there. Also, be sure to add a ground strap from your regulator to the engine (timing chest). Make sure all your grounds, and connections, are clean, tight, and "treated" . . . Caig DeOxit®, baby!
MartyNZ Posted March 16, 2020 Posted March 16, 2020 2 hours ago, guzziart said: I'm trying to understand why the ground wire at the ECU burned. How did high current flow from the ECU housing (that is mounted on electrically insolated vibration Imagine some previous owner is removing the battery; he starts undoing the +ve terminal first. Then the spanner slips and touches the ECU. 12v goes to ground through that little wire. Sparks or melting wires get your attention. Don't ask how I know. 3
LowRyter Posted March 16, 2020 Posted March 16, 2020 I'd take my fuse holder apart but the left side allen head is stripped out. Guzzi fasteners drive me nuts.
docc Posted March 16, 2020 Posted March 16, 2020 9 hours ago, LowRyter said: I'd take my fuse holder apart but the left side allen head is stripped out. Guzzi fasteners drive me nuts. The fuse block will actually pry up out of the rubber insulators without using the fasteners. A little at a time, back and forth between them. 1
LowRyter Posted March 16, 2020 Posted March 16, 2020 7 minutes ago, docc said: The fuse block will actually pry up out of the rubber insulators without using the fasteners. A little at a time, back and forth between them. Thanks Docc. Even though I was fearful of breaking the whole mess, I was well on my way of doing that but the bike finally restarted and ran. Glad to know it's possible to do that. (I have a feeling I'll be attempting a lot of bike "maintenance" over the next few months. You guys might be the few folks I'll be communicating to as well.) 2
guzziart Posted March 16, 2020 Posted March 16, 2020 Hi, Thanks for the comments! Docc: I'll be sure to double check all the ground connections. And, I'll ground the regulator case, thanks, I was wondering about that. I ohmed out the green ground leads from the VR to the case and got no continuity but didn't reverse the leads, forgot we're dealing with diodes, reverse polarity, etc. FWIW, my owners manual schematic indicates a vr housing ground while the schematic from the shop manual does not indicate the vr housing as being grounded...confusing but I'll ground it. MartyNZ: I think your right although I don't see any evidence of arcing at the ECU housing. Now I am trying to determine how far into the harness the damage goes. I hope it is confined to the foot or so of wire from the ecu to the batt neg. At this point, I guess I'll pull the bag mounts & tail section and begin cutting the harness open to assess damage. LR: I'll be sure to take a look underneath the fuse block asm. I pulled all the fuses, they were all clean and showed no sign of being stressed. Well, out to the garage I go, Thank you! Art
guzziart Posted March 16, 2020 Posted March 16, 2020 7 hours ago, guzziart said: Hi, Thanks for the comments! Docc: I'll be sure to double check all the ground connections. And, I'll ground the regulator case, thanks, I was wondering about that. I ohmed out the green ground leads from the VR to the case and got no continuity but didn't reverse the leads, forgot we're dealing with diodes, reverse polarity, etc. FWIW, my owners manual schematic indicates a vr housing ground while the schematic from the shop manual does not indicate the vr housing as being grounded...confusing but I'll ground it. MartyNZ: I think your right although I don't see any evidence of arcing at the ECU housing. Now I am trying to determine how far into the harness the damage goes. I hope it is confined to the foot or so of wire from the ecu to the batt neg. At this point, I guess I'll pull the bag mounts & tail section and begin cutting the harness open to assess damage. LR: I'll be sure to take a look underneath the fuse block asm. I pulled all the fuses, they were all clean and showed no sign of being stressed. Well, out to the garage I go, Thank you! Art Hi, Well, I got off easy with my burned wiring. I began cutting open the wire harness from the ECU and as luck would have it, only the one length of wire that runs from the ECU to batt neg was burnt...about an 18" length. So, I replaced the multi wire ring termiinal at batt neg, ran a fresh wire to the ECU ground with a new ring terminal and tied the timing sensor ground shield into it too. Marty, I think you suggested a piece of inner tube to aid in shielding the corner of the ECU closest to the batt + terminal, I did that too. I didn't realize something you said earlier until I began writing this just now. After I repaired the wiring, put the battery back in, I noticed the spanner laying next the the tool pouch so, I shoved it underneath the tool pouch rubber band to better secure it. You mentioned the possibilty of the spanner bouncing around and contacting the batt+ and shorting against the ECU or other ground in that neighborhood. In retrospect, that might be what happened....damned spanner! Docc, I rechecked all the grounds and added a ground to the VR housing to the timing chest. Thank you for your help & insight. Stay well! Art I 1
Tomchri Posted March 17, 2020 Posted March 17, 2020 1 hour ago, guzziart said: Hi, Well, I got off easy with my burned wiring. I began cutting open the wire harness from the ECU and as luck would have it, only the one length of wire that runs from the ECU to batt neg was burnt...about an 18" length. So, I replaced the multi wire ring termiinal at batt neg, ran a fresh wire to the ECU ground with a new ring terminal and tied the timing sensor ground shield into it too. Marty, I think you suggested a piece of inner tube to aid in shielding the corner of the ECU closest to the batt + terminal, I did that too. I didn't realize something you said earlier until I began writing this just now. After I repaired the wiring, put the battery back in, I noticed the spanner laying next the the tool pouch so, I shoved it underneath the tool pouch rubber band to better secure it. You mentioned the possibilty of the spanner bouncing around and contacting the batt+ and shorting against the ECU or other ground in that neighborhood. In retrospect, that might be what happened....damned spanner! Docc, I rechecked all the grounds and added a ground to the VR housing to the timing chest. Thank you for your help & insight. Stay well! Art I Someone suquested to leave the ground out from the harness, to avoid what happen to your bike. So I did a separat ground from the ECU to an extra ground terminal. Shoud be some pictures of it in the latest battery discusson Cheers tom.
footgoose Posted March 17, 2020 Posted March 17, 2020 On 3/15/2020 at 8:32 PM, docc said: Pretty sure it is not that the ECU had such a high ground demand, but that major ground demands (starter!!) were not being met and found their way back there. Also, be sure to from your regulator to the engine (timing chest). Make sure all your grounds, and connections, are clean, tight, and "treated" . . . Caig DeOxit®, baby! "add a ground strap" got a photo of this procedure Docc? (you spoiled us) #2--- how do you guys highlight bits of posts like I see sometimes in color?
Chuck Posted March 17, 2020 Posted March 17, 2020 #2--- how do you guys highlight bits of posts like I see sometimes in color? Hmm, Dunno. Aha, got it. Copy it to the clipboard, paste it into the post. Highlight it, go to the underlined A above, and you can change size and color.
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