GRiSO Relay not sending juice (different issue)

Hi, I see the stelvio relay thread, but my issue is a bit different.

I cut the gps lead to attach my garmin zumo xt. when I wired it up and turned the bike on, fuse B blew. I fixed it multiple times and then eventually capped the gps lead, and the fuse still blows when bike keys on. I can get the faint click from the starter relay, but nothing goes to the solenoid. I would find it hard to believe it is starter interruptus based on the fact that I have not had any other issues and the timing would be very coincidental.

Does anyone have any thoughts?

Also a weird thing, the lambda sensor was unplugged but bike was running great with aftermarket exhaust. Is this OK?

Check the polarity of your connections. You may have them reversed!

kiwi dave wrote:

Check the polarity of your connections.  You may have them reversed!

perhaps I did when they were connected, but since then I have capped the connection, so shouldn't that solve it?

For lambda part of question......

a) you can switch off/on lambda control on any map incl OEM quite easily (using eg TunerPro).
b) Could also be a 3rd party improved map like Mark's that disables lambda to fix low rev jerkiness but is tuned to your aftermarket exhaust etc...

if it runs fine, not worth chasing; else read the map & ask Mark for a better one for your situation !

aria wrote:

kiwi dave wrote:

Check the polarity of your connections.  You may have them reversed!

perhaps I did when they were connected, but since then I have capped the connection, so shouldn't that solve it?

I agree with the polarity check
assuming you had no issues with blown fuses prior to cutting the connector, I would guess that you have a short where you made the cut.
maybe there is a stray strand that is going to ground? or could you possibly have knicked the wires when working on it?



try pulling all available slack away from the bike and separating the conductors from each other - give it a good look over hopefully you'll find the culprit.

if this doesn't clear it up, you should use a multimeter to confirm the fuse in question is protecting the GPS circuit (ohm it out)- it's possible they aren't related.  maybe you disturbed something else that was on the edge of functioning when you were working with the harness

Did you try unplugging the Lamda sensor again?
I am having trouble making sense of this problem since my diagram has the fuses numbered.
[You must be registered and logged in to see this link.]
And its 4 AM here LOL
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In the light of day I found another diagram that labels fuse 2 as B so why does that fuse blow?
It's the same yellow wire I call the weak yellow feed, downstream of the ignition switch, assuming it blows when you turn the key On it must have a short in one of its circuits.
The number plate light is at the rear, it could be a wire shorting to ground in the fender area or the light itself.
The yellow also goes to the key switch and the left hand bar switch
Then it used to go to the two start relays.
Is it possible someone has done the Startus Interuptus fix and left the original yellow feed to short to ground, look around the relay area and see if you can find it.
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If it blows when you push the Start button, the solenoid pulls 40 - 50 Amps for a split second, the fuse needs to be a 15 Amp or a 20 if the SI fix has been done.

aria wrote:

perhaps I did when they were connected, but since then I have capped the connection, so shouldn't that solve it?

Not if you've done some damage.  The ECU probably doesn't like reversed polarity connections, the easiest way to prove may be trying a known good one as a substitute (and hope any damage that has occurred doesn't take this one out as well).

Its pretty hard to put the power on the ECU backwards it has a special relay to prevent that happening.
Relay (28) has a diode in series with the coil (doesn't really show it on the schematic I attached) but it's shown on the Black & White drawing I downloaded this morning.
If you accidentally reverse the battery a "Safety Diode" prevents the relay coil energizing and that prevents the other Injection relay energizing as well.
You could draw a diode inside the relay pointing to terminal 85, easy to verify it's there if you have a meter with diode test.
Look at a similar bike from the same era and it will show the diode.
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The first fuel injected bikes from Guzzi used all the same type of relay but the critical ones had an external diode to chassis serving the same purpose.
For some reason Guzzi went away from that idea and provided a different type of relay with the diode inside, a mistake IMHO, now you need two spares.
Here's an earlier bike that clearly shows the Safety Diode (48), it's more obvious. [You must be registered and logged in to see this link.]
Even the very first bikes with the old P8 ECU had this feature but on those the diode was inside the ECU, I have replaced a couple of those when they got blown accidentally.

Kiwi_Roy wrote:

Did you try unplugging the Lamda sensor again?
I am having trouble making sense of this problem since my diagram has the fuses numbered.
[You must be registered and logged in to see this link.]
And its 4 AM here LOL
--------------------------
In the light of day I found another diagram that labels fuse 2 as B so why does that fuse blow?
It's the same yellow wire I call the weak yellow feed, downstream of the ignition switch, assuming it blows when you turn the key On it must have a short in one of its circuits.
The number plate light is at the rear, it could be a wire shorting to ground in the fender area or the light itself.
The yellow also goes to the key switch and the left hand bar switch
Then it used to go to the two start relays.
Is it possible someone has done the Startus Interuptus fix and left the original yellow feed to short to ground, look around the relay area and see if you can find it.
--------------------------
If it blows when you push the Start button, the solenoid pulls 40 - 50 Amps for a split second, the fuse needs to be a 15 Amp or a 20 if the SI fix has been done.

Thanks, I did unplug the lambda sensor again. If it were the startus interruptus, would it blow when keyed on?

The fuse B blows once the key is turned on. The taillight and turn signals work, does that rule them out? Perhaps it is the ignition

No Startus Interuptus is more a lack of current caused by too much resistance rather than too much. You can check if its been done by removing the Start relay and seeing if the terminal 3 is alive with the key turned Off, If alive it's been done, of course the extra relay socket would be a dead give-away.
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Theres not that much on fuse 2.
I think the wire is Yellow, you can check on that at the fuse.
The Numberplate light (18), pull that apart and inspect the length of wire where it passes along the rear fender, this is the most likely place for it to short.
It also goes to the key switch and the left hand switch to power up the pass light, I doubt it would be there, you can unplug the connector under the tank to isolate that.
Then it used to go to pin 3 of relay 2 and pin 30 of relay 3.
I asked if someone had done the Startus Interuptus fix, if they did it's possible there's a lose yellow wire around the relay area shorting to chassis.
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Often when looking for a short in the wiring I use an old sparky trick substituting a high wattage lamp for the fuse. A couple of wires soldered to an old headlight bulb plugged into the fuse holder.
When you have a short on the circuit the lamp glows at full brightness, wiggling wires eventually you will lift the short and the lamp will go out or dim, its very visual and no fuses are harmed in the process.
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Something else you can do is Ohm the circuit out, remove the fuse and plug your meter into the load side of the fuse and chassis, it should read a few Ohms being the Plate lamp but I suspect its a dead short to ground.