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V11 Will not start


milo
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It is helpful to distinguish, when a V11 "won't start", whether it *clicks/whirs, cranks, or that there is > nothing < at all.

Both @LaGrasta and @milo's V11 crank, but don't fire (if I understand correctly). A V11 with a faulty Run Switch or bad Clutch Switch/bullet connectors doesn't do anything on start attempt?

Also, just because the battery has been removed for storage = nothing electrical can go wrong? I would venture that connections can continue to corrode and degrade while rodents can change your wiring without asking. Rude little shits. :bbblll:

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9 hours ago, milo said:

... voltage drops from 12.5 to 4.5V  as soon as i turn on the ignition so looks like i'll be having another Guzzi electrical fault finding session... can't imagine what could have happened to the electrical system in the intervening period.

Electrical connections will degrade over time, and any 12v system is vulnerable to increased resistance from corrosion. Oxygen and Humidity cause this. Imagine how much more trouble a vintage 6v system was. I'd disconnect the ground lead to the gearbox first. Get clean shiny metal to metal faces, re-assembled with grease. Battery terminals next. A voltage drop to 4.5v means a bad battery &/or bad connections.

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Just to recap on my original post with more detail , before i attempted to start the bike I fitted a NEW ODYSSEY PC545 Battery , NEW PIERBURG - 7.21287.53.0 fuel pump , NEW set of Bosch relays , checked the BCM air filter that didn't have a spec of dust on it , emptied the tank and filled with new fuel , checked the plugs were sparking , checked that there was fuel pressure at the injectors which there was then i attempted to start the bike, cranks over perfect but won't start as there is no fuel getting injected.

MartyNZ - Been there myself with the old 6V bikes forever cleaning the terminals but the V11 although not the best connectors are fairly tight and well sealed but not to say i haven't had the odd wiring issue in the past as with all Italian bikes, also the bike has always been kept in underground parking so not a hint of humidity or oxidation to be found on it , what i've disconnected so far has all been really clean connections . 

As there are quite a few leads connected to the battery i thought i'd start at the source to check for faults so i removed the 3 negative leads and reconnected one at a time and found with one of the leads disconnected i had a constant 12V at the injectors with ignition on, when i connect the third wire it drops again to 4.5V. The wire in question is a bundle of 3 one of which goes to the ECU relay then the other two not sure as yet (maybe ECU also) but need to do more tests to verify.

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I'm no expert, but that kind of voltage drop smacks of "dead short." :o

Could there be something awry with the four hidden spade connectors beneath fuses one and two (injection/ ECU)?
 gallery_328_223_160743.jpeg

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The three negative ring terminals on the battery are: 1) the largest/ main ground to the back of the gearbox (be absolutely certain this connection to the gearbox is cleaned bare and sealed!), 2) the start/charge/lights harness, and 3) the (completely separate) Fuel/Ignition harness through fuses 1 & 2 --> Relays 4 & 5.

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Open circuit voltage should always be system voltage. So if you measure the ground for the injectors (and whatever else) it should show battery voltage when disconnected but nearly zero when attached properly. That is, testing from ground wire to ground. Whatever voltage you see between the ground wire and ground is resistance, and to be eradicated as a connection fault.

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So the 3 wire bundle negative terminal i was looking at, one goes to ECU relay then diagnostic plug then the other two go direct to the ECU so basically without this negative on the ECU its turned off and i get 12V at the injector plug, things didn't really seem to add up but I read somewhere when looking for injector info that some systems only have +12V at the injector when cranking or running but looking at the Guzzi diagram it would appear that the coils, fuel pump and injectors should all have 12V when the relay closes. So i reconnected the ECU negative, cranked it over and i'm getting 10.2V at the Injector when cranking so i led myself astray chasing the low voltage fault. Next i looked at the injection relay and if moved around pulled out a bit i get 11.2V at the injector when cranking so almost there , i've got a spare relay base somewhere so i'll try fitting that next time. 

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Or take the cable lugs  (connectors) out from the r base and squese them for a tight fit. Caig Deoxit and white vaseline is medisin. It's a good idea to remove the ground coming from the harness, going to the outside of the ECU. A separate ground is adviseable.  Better relays when time comes to. Your close, and learning to know your bike. 

Cheers Tom.

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  • 4 weeks later...

Been away with work for a while so just got back to the Guzzi , i bench tested the injection relay and found it to be faulty so replaced with another new one and all ok with the voltage now, the relay was a brand new Bosch but not the first time i’ve fitted an electrical component out the box and it didn’t work. But the bike still won’t start. 

 

Going back to my original question from this post “ Is there a way to test the injectors or ECU signal? “  When the ignition is turned on there is 12V on the injection relay circuit for a second, the fuel pump turns on for a second then stops because its voltage feed is dropped to 3.5V by the ECU. So to test the voltage for the injectors there is 3.5V at the plug with ignition on and 12V intermittently when cranking. 

I took the injectors out and connected a 12V battery with a push button to test. Pushed the button for a second , nothing , pushed for two seconds, nothing , pushed for three seconds the solenoid clicks , again for three seconds it clicks then two seconds it clicks then one second it clicks then immediately , so on/off a few times and works fine. I filled the injector body with fuel put 3bar air pressure on it pushed the button and got a nice perfect spray pattern , did it a couple more times then repeated the same process with the other injector. Fitted the injectors , a couple of crank overs to prime then it fired up and went onto a nice steady idle, so works great now. 

So the fault was the injector solenoids had been sat for too long and they just needed a bit more than a quick flash of 12V to kick them of their seats again. 

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