PLEASE help with no spark

[Teddo]

After a couple years of ownership my beloved V7iii Racer won't spark! Just out of the blue. I was looking forward to a nice summer evening ride when it wouldn't start. Turns over fine, battery is strong, has not been wet - always keep indoors. I checked for spark by grounding the plugs, I've taken off the seat to check for anything obvious - all connectors are solid - fuses are good, tried rebooting the ECU by disconnecting the battery. Guzzidiag shows no faults. I'm now hoping someone out there could suggest a checklist for no spark. My knowledge of motorcycle electronics pretty much ends with 70's Hondas! I do want to do all I can before resorting to hauling it over to the dealer, I might learn something. I do have a multimeter. Any help would be greatly appreciated! The bike has less than 4000 mi and is always pampered - I just don't get it.

[lucian]

Check the easy stuff first, Kill switch ?  Side stand switch?  You can unplug the side stand switch , just follow the wire up to the connector. More knowledgeable folks on the newer small blocks will be along shortly.

[Huzo]

+1 to Lucian.
Losing both plugs is significant. As Lucian says, check those things. I would disconnect the side stand switch and rig the wires so the bike thinks the stand is retracted.
Also put 12 into the switch through a test lead and check it’s function.
I presume the switch has to be closed for the bike to start, but not necessarily.

Start on the kill switch and spray some contact cleaner in there before getting serious.

[Teddo]

Thanks guys for the quick response! I did try  with the side stand up and I figured it wouldn't be the kill switch since the starter motor works ?

[Kev m]

Thanks guys for the quick response! I did try  with the side stand up and I figured it wouldn't be the kill switch since the starter motor works ?

Motor spins and you're POSITIVE there's no spark?

Time to check the ignition coil primary circuit.

[Teddo]

Right, starter motor works but no spark on either side, whats the chance of both coils bad?

[moto-uno]

 Is there a crank position sensor on these bikes ? If so , and it's accessible , try removing it and checking for debris on it . Peter

[Kev m]

Right, starter motor works but no spark on either side, whats the chance of both coils bad?

I didn't mean to suggest they were bad per se (sorry I could have said that better). I meant you need to see if there's power on the primary circuit. What powers them/what brings them. Once you're sure that's not happening then you've further narrowed the problem.

It could be the engine stop switch, but I thought it wouldn't crank without that working. What part of that circuit cuts ignition?

Moto - you might be right but I would assume a problem with the CKP sensor would throw a code, no?

[Teddo]

Ok I thought you were thinking  resistance, I'll ck for power to the coils..

[Huzo]

Thanks guys for the quick response! I did try  with the side stand up and I figured it wouldn't be the kill switch since the starter motor works ?

Yeah good point.
I just checked with my V85 and with the kill switch “off” it will not crank.
With the side stand down, the bike will crank and start but will cut out if you engage a gear.
So.

IF your bike is the same, the plugs should spark with the stand in any condition.
Is there a single fuse protecting that circuit ?

[lucian]

Try swapping around some relays

[Vagrant]

Yes, swap the relays. Some ignition switches break wires off the back. Research it here. Rock the kill switch back and forth a few times too.

[Teddo]

Can't find any voltage going to the coils. ( probed the spades in the connector with key on) Also tried swapping the relays. Huzo I checked all the fuses for resistance they looked good.

[Kev m]

Can't find any voltage going to the coils. ( probed the spades in the connector with key on) Also tried swapping the relays.

 

Time to pull out the wiring diagram and trace the circuit, but you're almost there!

[Teddo]

Kev -Well according to the fuzzy diagram in the pdf SM the power seems to came from the  ECU or injection loads relay - whatever one that is?
OK an update - I reran Guzzidiag thinking I overlooked something an got a fault - p0336 invalid engine speed signal so I'll take a look maybe some obvious at the sensor

[Kev m]

Kev -Well according to the fuzzy diagram in the pdf SM the power seems to came from the  ECU or injection loads relay - whatever one that is?
OK an update - I reran Guzzidiag thinking I overlooked something an got a fault - p0336 invalid engine speed signal so I'll take a look maybe some obvious at the sensor

Boom.

Crankshaft Position Sensor is used to tell the ECU when to time both fuel and ignition. Without it the ECU cannot run and cuts power to the ignition and the EFI system.

[Teddo]

Sensor looks fine - no obvious obstruction or misalignment - for 0336 SM suggests checking to see if "electric circuit is in good conditions"

[Kev m]

Sensor looks fine - no obvious obstruction or misalignment - for 0336 SM suggests checking to see if "electric circuit is in good conditions"

A code simply means that component's circuit isn't giving the right signal to the ECU. So yeah, you don't just assume the component is bad, you first check the harness and the connectors for problems (loose/disconnected/corroded connectors and pins). But the sensor can be bad too.

I just replaced a wheel speed sensor on the Jeep. Just went udders skywards last Tuesday, no rhyme or reason. Same idea a simple hall effect sensor.

[Vagrant]

If you search posts by SmithSweede you will find a ton of info on that sensor including where to buy them cheap.

[Tom H]

I think it should have about 680 ohms resistance between the wires in the plug.

Tom

[Huzo]

How hard is it to borrow one and see if she fires ?

[lucian]

I think it should have about 680 ohms resistance between the wires in the plug.

Tom

This^ but also you can check to see if it generates ac voltage when you crank the motor over , Should be 1 to 2 volts.
 Also ,the injection relay may be under the tank on the viii

[Teddo]

Well the crank sensor appears to be open - I get nothing when probing for ohms across the 3 spades in the plug - I'll shop for a new one. But does that explain getting no voltage to the coils? Also why P0336 and not P0335?

[Tom H]

If your is the same as like a '15 and don't mind a used one, try Mark at Moto Guzzi Classics in Signal Hill Ca..

If all the relays are good, battery good, connections clean and tight it should run. If this sensor goes bad, the ECU does not know when to add fuel or spark.

I doubt both coils would have gone bad. You can pull a plug cap and stick your meter in it and the other lead to ground, you should have about 8 ohms resistance, at least my EVT does. That might tell you if a coil has gone bad.

Good luck,
Tom

[Teddo]

My bike is a different generation - V7iii - I found a new one at AF1 racing for $33.80 plus shipping. (OEM Aprilia Crank Position Sensor - 6389915). I hope this doesn't wind up as just a spare. Thank you guys for all your help! I'll check in when I get the part.

[Chuck in Indiana]

Looks as if you have found the problem. I *assume* the sensor gap needs to be checked when installing the new one? I have *no* experience with the modern small blocks.

[Tom]

Crank position sensors when they go out aren't visible for failures.  The engine speed signal showing as the code would indicate a replacement needed.  Good luck! 

[lucian]

Well the crank sensor appears to be open - I get nothing when probing for ohms across the 3 spades in the plug - I'll shop for a new one. But does that explain getting no voltage to the coils? Also why P0336 and not P0335?

 The three wire sensors need 12 v power to test , you need to determine which wire is power + by back probing the connector with a paper clip or needle inserted to the back of the connections. with key on one wire should show 12 v.  Next set your meter to ohms and check  which of the other two wires  is common to ground, The remaining wire is the signal wire which should show 1-2v when cranking  the engine. When checking the sensor for resistance, you need to check between the signal wire and  the ground wire

[Bulldog9]

If your is the same as like a '15 and don't mind a used one, try Mark at Moto Guzzi Classics in Signal Hill Ca..

If all the relays are good, battery good, connections clean and tight it should run. If this sensor goes bad, the ECU does not know when to add fuel or spark.

I doubt both coils would have gone bad. You can pull a plug cap and stick your meter in it and the other lead to ground, you should have about 8 ohms resistance, at least my EVT does. That might tell you if a coil has gone bad.

Good luck,
Tom

You raise a good point. If it is just coil circuit, I would expect the ECU to pump fuel for startup. In this case, the plugs would/should be wet. 

If they are wet, it is unlikely the CPS or ECU, but power to the coils. If the plugs are dry and no clear gas smell, I'd look first at the CPS then ECU.

I've read in a couple places about the wires breaking off the back of the ignition switch.

A sudden change tells me it is likely the sensor, but I've not had to chase these things down on my bikes, so am unfamiliar with the wiles of the V7 ECU & such.  This forum will help you track it down!

[Kev m]

You raise a good point. If it is just coil circuit, I would expect the ECU to pump fuel for startup. In this case, the plugs would/should be wet. 

If they are wet, it is unlikely the CPS or ECU, but power to the coils. If the plugs are dry and no clear gas smell, I'd look first at the CPS then ECU.

I've read in a couple places about the wires breaking off the back of the ignition switch.

A sudden change tells me it is likely the sensor, but I've not had to chase these things down on my bikes, so am unfamiliar with the wiles of the V7 ECU & such.  This forum will help you track it down!

Most EFI systems that don't have a redundant way to track engine speed to determine ignition and EFI timing will CUT both ignition and fuel with a CKP sensor failure. It stops triggering the ignition coils and stops fuel injectorv pulsing.

So no wet plugs.