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Voltage to ECM?


CurtBrass

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What is voltage that I should be getting to the ECM? Coming out of the 30 Amp Main fuse A, I am getting 12+ volts at the red wire, but only 0.50 volts at both the Green/Red and Yellow/Red wires. 

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Why are you testing the ECU wires?  That's not part of any normal diagnostic procedure.

 

Ciao,

 

JZH

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I'm getting no power from the ECU to my Fuel Cut Relay and my Engine Stop Relay via the Black/White wire. I tapped the Black/White wire out of the ECU and no power there. So I checked the voltage in and only getting 0.50 volts at the Green /Red wire, which seems to be the only power source for the ECU.

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Based on the wiring diagram, at the main fuse the red and green/red share a common terminal at the main fuse so I'd go looking in there. I agree that you should be seeing 12v at the green red terminal at the ECU. 

 

VFR_Wiring_Layers_hires_full_(2).png

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image.png.551c9d5b127f966320a481836519bda6.png

Yeah, so when I test the output at the starter relay switch, I am getting 12+ volts at the red wire, but only 0.50 at both the Yellow/Red and the Green/Red. Perhaps the plug is fried, but I don't want to put put 12V to the ECU if it'll blow it out. So if anyone knows, I would really appreciate it.  

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On 29 April 2019 at 10:53 AM, CurtBrass said:

image.png.551c9d5b127f966320a481836519bda6.png

Yeah, so when I test the output at the starter relay switch, I am getting 12+ volts at the red wire, but only 0.50 at both the Yellow/Red and the Green/Red. Perhaps the plug is fried, but I don't want to put put 12V to the ECU if it'll blow it out. So if anyone knows, I would really appreciate it.  

Hi CurtBrass.

NO NO NO! That drawing is deceiving.  The 12v is ONLY at the Red Wire (and of course the R/W wire).  The G/R is a ground wire for the Starter Relay coil, via the Clutch Switch and Side Stand or the Neutral Switch. The Y/R wire goes to the Start Switch and is eventually the +12v for the Starter Relay coil.

 

The G/R wire is NOT Power to the ECM. ECM 12v power is fed from the Engine Stop Relay to B8 at the ECM (according to the schematic) a Bl/W wire.

 

What looks like a join or link between the Red and the G/R wires its NOT, its just showing a 4P Connector graphic!

 

Your Engine Stop Relay needs to energise BEFORE you see power at the ECM and Fuel Pump. So check your Kill switch and your Bank Angle Sensor. You Must get the Engine Stop Relay Energised at ignition switch on first.

 

So a WARNING - Do not go and apply 12v to the G/R wire in attempt to power the ECM. The G/R wire is telling the ECM status of the Clutch and Neutral Switch!

 

image.png

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Thank you! I’m glad that I waited for someone who knows their way around this! I’ll check through the bank angle and kill switch. 

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On 29 April 2019 at 7:30 AM, CurtBrass said:

I'm getting no power from the ECU to my Fuel Cut Relay and my Engine Stop Relay via the Black/White wire. I tapped the Black/White wire out of the ECU and no power there. So I checked the voltage in and only getting 0.50 volts at the Green /Red wire, which seems to be the only power source for the ECU.

Hi CurtBrass.

Glad I caught you before you were going to smoke up your ECM and wiring. I'm trying to work out exactly what your bike issues are?

Does it crank but not start? And definelty no Fuel Pump 2 second prime at switch on?

Firstly using the wiring diagram establish the correct voltages and operation of the Engine Stop Relay then move onto the Fuel Cut Relay. If you suspect a faulty relay you can swap it with any of the others, your Hi Beam Relay is a good one to grab.

Assume you have checked the relavent Fuses? 

The Bank Angle Sensor controls the ground side of the Engine Stop Relay coil, so it's easy to bypass the BAS for fault finding purposes. So here's another confusing thing about the Engine Stop Relay coil wires, the Black wire is the Positive and the Red/Orange is the Negative (Ground) provided by the BAS.!

Keep us informed with what you find.

Good luck.

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Hi Grum,

Thank you for all the knowledge. I'm a complete novice at this stuff, and this forum is an invaluable resource.

 

Here's a synopsis of my issue. Maybe more detail than necessary, but one of the details might be important:

- Last fall, a week before I was going to put it away for winter, my bike died on me. It would crank, but no fuel pump prime. 

- Replaced fuel pump fuse, blew immediately (I've spent a small fortune on 20 amp fuses trying to find the short).

- I had been blowing headlights during the summer, figured that it must be related.

- Following advice on this site, checked the stator and R/R. Both looked to be shot, and the connector was black and burnt, so replaced both as well as the battery. But they wouldn't be causing my short circuit, although bad voltage out of them probably contributed. 

- Also replaced headlight wiring with Eastern Beaver H4 assembly, headlights work when key turned on.

- I provided direct 12v power and ground to the fuel pump and it runs fine, but even when this is done it won't fire.

- The problem seems to centre around the engine stop relay. With the key turned on, I get 12+ volts at three of the terminals: Black, Red/Orange and Black/Purple. I get 0.0 volts at the Black/White terminal. I also get 12+ volts at all three wires at the Engine Stop Sensor (BAS). 

- I've tried three different relays at the Engine Stop Relay location, but I still get nothing at the Black/White wire. 

 

So, Is that right? Any thoughts on why I'm not getting any voltage to the Black/White wire? 

 

 

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10 hours ago, CurtBrass said:

- The problem seems to centre around the engine stop relay. With the key turned on, I get 12+ volts at three of the terminals: Black, Red/Orange and Black/Purple. I get 0.0 volts at the Black/White terminal. I also get 12+ volts at all three wires at the Engine Stop Sensor (BAS). 

- I've tried three different relays at the Engine Stop Relay location, but I still get nothing at the Black/White wire. 

You appear to have established a faulty BAS, OR its wiring.

 

As mentioned the BAS provides the Engine Stop Relay coil Ground via the R/O wire through the BAS to the Green ground wire of the BAS. Without this Ground line the Engine Stop Relay cannot energize.

 

Your statement " I get 12v at all three wires of the BAS" should NOT be the case, the Green wire of the BAS is GROUND! In fact the same Ground wire the Fuel Pump uses. You should ONLY be seeing 12v on the BAS at the W/Blk wire in normal operation.

 

With your voltmeter black lead ideally on the Negative Battery terminal and your red voltmeter lead probing the BAS Green wire you MUST see 0v. If NOT then unplug the BAS and make sure the Green wire is properly connected to Ground as it needs to be (continuity check to Ground). Irrespective of your meter results MAKE SURE the Green BAS wire is properly GROUNDED as this appears to be your Main fault.

 

To verify your Engine Stop Relay works you can simply probe a temporary Ground wire to the R/O wire. With Ignition On you should hear the relay energize and hopefully your Fuel Pump Prime! 

 

As previously mentioned. You will NOT have any volts on the Black/White wire until the Engine Stop Relay energizes, that's it's job!

 

Get back to us after these checks.

Cheers.

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I would maybe NOT overlook checking the proper mounting POSITION of the BAS first. Because if it's not mounted in its proper position (i.e. in its -or at least pretty close to its- proper angle), you may get strange and at least unexpected results anyhow...

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