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2014 V7 ECU Dead short

My new ECU arrived yesterday, a day ahead of schedule. Woo hoo! The moment I had it unboxed I checked for an electrical connection between pin 9 and ground/pin7/pin23. Nope. Nothing. So 100% confirmed my old ECU is internally shorted to ground.

Now the big question: Will my new ECU go "poof" the moment I plug it in as I've thus far not found the reason the old one shorted out in the first place. Yikes!
 
I would do a continuity test on the wires associated with those pins first. Lot of work to be safe. It could have just been a marginal ecu to begin with from mfg.
Looks like you already had it all apart doing just that.
 
I would do a continuity test on the wires associated with those pins first. Lot of work to be safe. It could have just been a marginal ecu to begin with from mfg.
Looks like you already had it all apart doing just that.
Yep! Did that as part of the tear down and diagnostics. Checked that circuit from the fuse to the ECU for continuity, shorts to power, ground, or other circuits. As far as I can tell the harness is solid.
 
Anyone know if after installing the new ECU I'll have to do any sort of flashing to my specific serial number? Or can I just swap it in and do the throttle position calibration courtesy of my GTM flash tool?
 
Anyone know if after installing the new ECU I'll have to do any sort of flashing to my specific serial number? Or can I just swap it in and do the throttle position calibration courtesy of my GTM flash tool?
Swap, reset and go.
 
Update time! New ECU is in and the harness is installed. Fired it up and it runs! Not well, but it's running. One step at a time I guess. Now I've got a P0115 (engine temp sensor) error code. Some more diagnostics in my future I see.
 
Update time! New ECU is in and the harness is installed. Fired it up and it runs! Not well, but it's running. One step at a time I guess. Now I've got a P0115 (engine temp sensor) error code. Some more diagnostics in my future I see.
Good news, and well, you have a stock map again now, correct? It will only run as good as that allows unfortunately. Clear the error(s) and ride again. Could be an anomaly. If it appears again, replace the sensor.
 
Oh man, you guys will never let me live this one down... I had the temp sensor and injector connectors swapped. All good now. Runs like a top!

IMG 5682
 
This swap over would have occurred when the harness was replaced, I'm guessing. So is your original ECU is still toast?
Correct. I meticulously labeled and photographed the main harness connections, routing, every zip tie I cut, etc. All in an effort to get that harness back in exactly as it came from the factory. It was past midnight when I made those last few connections and being tired got the best of me I guess.

Yeah, the original ECU is toast. Got the new one off E-Bay for $149 and so far it's working fantastic.
 
Just in case anyone is curious. I found the culprit upon disassembly of the ECU to inspect the PCBA.

Failed component circled. Also, note the screw to the right of that component. Thats a mounting screw that holds the PCBA down to the cast metal enclosure. When that screw is snugged down the power in pin on the ECU shorts to ground. When I remove that screw the short goes away. Fun stuff. Hard to tell if the short to ground blew that component or of the component exploded and grounded out a copper trace.

MIU ECU Short
 
Thanks for the pic of the guilty party. Does it look like the component could be replaced and the ECU made functional again?
Possibly. I'd first have to ID that component and unfortunately the manufacturer's markings are all faded and right in the middle of the damage. I'd have to have an electronics expert reverse engineer what it is, then find a suitable replacement, then replace it on the board. I already have my $149 E-Bay replacement on the bike and running so this one will go in the spare parts bin for a rainy day. Not worth my time to try to save it!
 
Could you take the replacement ECU apart, or don't you want to temp fate.
I mean, sure. I could. But as you said, why tempt fate. The bike is running, the sun is out, the money on the new ECU is already spent. Why take the bike down to remove the ECU and open it up? Id rather be riding!
 
The blown component looks like a surface mount diode, two terminal device and an mark for the cathode

I Think it's an electrolytic Capacitor. I'm looking at one right now on a completely different circuit board (nothing to do with Guzzi's or ECUs) and the PCB has an identical shaped component labelled C88. Being electrolitic they need to be soldered in correctly hence the marking indicating the positive end of the cap, otherwise they blow up (but this can happen for other reasons too like age or excessive voltage). Looks like it blew up to me.
 
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