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Old August 12th, 2017, 09:17 PM   #35
DannoXYZ
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Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by gitter View Post
ok so i unplugged the gauge cluster.

left coil still plugged in, unplugged right coil ( green/red) cranked it over, 'noid light lit up.

Right coil plugged in, left coil (black/red) unplugged, cranked it over, 'noid light didnt light up.

does that point to a faulty ecu? if so, how does that point to a faulty ecu?
  • Testing grounds seems to indicate some sort of short on black-wire.
  • Disconnecting gauge-connectors removes short on black-wire
  • You've verified that the black-wire is intact from ECU-connector up to space-connector @ coil.
  • Noid-light shows signal on green wire at coil and at ECU connector
  • Noid-light shows NO signal on black at coil and at ECU connector.
I think this process of elimination and boolean-logic narrows down problem to no signal coming out of black terminal at ECU.

Here's final test & confirmation of bad ECU:

1. unplug both spark-plug wires from plugs
2. disconnect gauges
3. disconnect black wire spade-connector from left-coil
4. connect empty left-coil signal terminal to right-coil signal terminal (green). You can use a test-lead with alligator clips and back out green spade-connector slightly.
5. use 'noid-light and test right-coil when cranking
6. use 'noid-light and test left-coil when cranking

Do you get flashing at both coils now? If yes, plug spark-wires back in and run bike. Does it run on both cylinders? Only do this short-term, 10-15sec. max.

Now, you still have wiring issue, and it very well could be that short damaged ECU driver on left side. So we want to track down that short and fix it otherwise new ECU will be damaged as well.

Last futzed with by DannoXYZ; August 13th, 2017 at 09:12 AM.
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