HELP! Breva 750 won't run!

[thechief86]

Hey folks, I have a 2004 Breva 750 that I ride every day, and usually do about 600 miles a week.
I rode 1100 miles in 4 days for the 4th of July, and then rode to work today. When I stopped for gas on my way home, I noticed one spark plug was loose, and I had some new ones in the saddle bags, so I installed them. When I went to start the bike, it would fire, then die after 1 second and not start back. If I cycled the ignition, the fuel pump would prime and do its thing, and it would fire, then immediately die.
I swapped the old plugs back in, no change. Unhooked the battery, no change.
Had it towed home by a friend, then tried turning it over with a spark plug grounded to the engine, and what I found was that it has spark for about 1 second, then doesn't. Test probe shows that the fuel pump is working, as does the wet plugs and smell of gas from the exhaust.
Should I be looking at coils, or the ECU? Does it have a separate CDI box?
I have very little money at the moment, as my wife and I are having a baby next month.

2004 Breva 750, k&n style air filter, slip-on mufflers, power commander III. I get the same results with the power commander uninstalled.

[thechief86]

[oldbike54]

 Plug wire caps ?

 Dusty

[thechief86]

I'd love it if that were the issue, but those are in great shape.
I was wondering if maybe I had pulled on the plug wires too hard when I swapped the plugs, but I couldn't imagine that causing a consistently repeatable problem that is the same on both cylinders?
Same logic on the coils, as I would think it would at least run on one cylinder. I would be surprised if both coils crapped the bed at the same time...

[Arizona Wayne]

There's an item at the middle/back of all the relays/etc. under the seat rubber mounted that has 2 wires.  1 is black/white.  Did you for any reason futz with it? If it is installed upside down your bike will not run.  I learned this the hard way. 

[Kiwi_Roy]

Could it be the timing sensor (2) not picking up that the engine is turning over and shutting off the spark?
Try to monitor the ECU power relay, see if it's dropping out.

I think Wayne is referring to the bank angle sensor (42).
Update, Thanks Wayne, the bank angle sensor is either open or closed try unplugging then shorting it out

http://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif

I very much doubt there is anything wrong with the ECU, more likely to be something you disturbed.

[Arizona Wayne]

Could it be the timing sensor (2) not picking up that the engine is turning over and shutting off the spark?
Try to monitor the ECU power relay, see if it's dropping out.

I think Wayne is referring to the bank angle sensor (42).

http://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif

Yeah, that's what I'm referring to.  Cost me more $ than I want to admit. 

[CalVin2007]

 Also check/disable the kill switch and sidestand switches....you never know.

   Terry

[pete roper]

Was it a hot day? My guess phase sensor.

Pete

[thechief86]

There's an item at the middle/back of all the relays/etc. under the seat rubber mounted that has 2 wires.  1 is black/white.  Did you for any reason futz with it? If it is installed upside down your bike will not run.  I learned this the hard way. 

DING DING DING! We have a winner! I don't know how I overlooked this.
The power commander is mounted directly under this switch behind the battery. When I pulled the power commander out to fiddle with the fuel map, I put the bank angle sensor back in upside down.
I flipped it this morning and the bike runs like a top again. It's very out of character for this bike to be anything but perfect. For 20k miles I have only done regular maintenance such as tires, brakes, oil changes and a battery, and it has been the most dependable thing I've ever owned. Since I got this bike, I haven't driven either of my cars  more than once or twice a month, lol.
Thanks a lot! Even.a simple issue like this was much easier to deal with thanks to this forum.
Now to find someone to get power commander fuel maps from....

[sign216]

You're making me laugh.  I was searching my mind for the problem, and it's just an upside down sensor.

I just made a map for my 09 V7 on MyECU.  Not sure if it's compatible with the Power Cmdr system, but you could look at it.

[pete roper]

It's got a bloody arrow on it and the legend 'Up'. Glad you fixed it easily.

Pete

[thechief86]

Yeah, I noticed the arrow when I checked to see if that was the problem. Since I had messed with spark plugs and the power commander, I thought I had somehow fried the coils or ecu... everybody's a dummy sometimes.

Sign216, tell me more about your ecu map deal? Pm if you don't want it in this dumb thread haha

[Noguzznoglory]

Just for my own edification, what is the purpose of the bank angle sensor?

[CalVin2007]

 It disables the fuel pump (except for "initial prime" function) and spark if the bike tips over. A safety thing...

[thechief86]

In case you crash or drop the bike, it tells the ecu to kill the ignition so it won't keep running and screw something up.

[oldbike54]

 So all you really needed to do was ride upside down  Is there an arrow on new bikes that indicates this side up ?

  Dusty

[Noguzznoglory]

Ash. Same function as the ASD circuit on emi autos

[Arizona Wayne]

1 time before I ended up paying a dealer to find my problem I got the bike to run with that sensor upside down.   It ran fine until I got to  low revs like turning around and it died again.  Ended up needing a tow then.  Pete says there's an arrow on it but the whole thing is black and it's not easy to see.  I had no idea what that item was for.