Wildguzzi.com
General Category => General Discussion => Topic started by: Teddo on August 28, 2022, 05:30:28 PM
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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.
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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.
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+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.
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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 ?
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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.
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Right, starter motor works but no spark on either side, whats the chance of both coils bad?
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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
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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?
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Ok I thought you were thinking resistance, I'll ck for power to the coils..
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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 ?
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Try swapping around some relays
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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.
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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.
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Can't find any voltage going to the coils. ( probed the spades in the connector with key on) Also tried swapping the relays.
:thumb:
Time to pull out the wiring diagram and trace the circuit, but you're almost there!
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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
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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.
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Sensor looks fine - no obvious obstruction or misalignment - for 0336 SM suggests checking to see if "electric circuit is in good conditions"
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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.
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If you search posts by SmithSweede you will find a ton of info on that sensor including where to buy them cheap.
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I think it should have about 680 ohms resistance between the wires in the plug.
Tom
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How hard is it to borrow one and see if she fires ?
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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
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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?
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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
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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.
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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.
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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!
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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
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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!
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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.
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As I recall the plugs did seem pretty dry.
I'm thinking of replacing my fuel filter while I have the tank off (was a struggle getting that vent hose off!) with an all metal one - any suggestions?
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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.
Right, but if the CKP/CPS - ( meaning crank position sensor) is good, the ECU would trigger the fuel and spark, but if the coil is bad no big bang......
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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.
Still wondering why I don't get current to the coils - I would think that the coils are normally charged ( with key on ) and the ecu , via the CPS, would cut power for the spark, no? I visualize the CPS/ECU doing the job that points did.
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All the sensor does is pick up a gap in the teeth on the tone wheel which triggers the ecu to send signal to the coils.
I doubt both coils went bad at same time.
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All the sensor does is pick up a gap in the teeth on the tone wheel which triggers the ecu to send signal to the coils.
I doubt both coils went bad at same time.
Is the signal to cut power to generate the spark? If so wouldn't the coils be energized between signals?
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Right, but if the CKP/CPS - ( meaning crank position sensor) is good, the ECU would trigger the fuel and spark, but if the coil is bad no big bang......
The ECU triggers the coil BASED on the CKP signal.
The TWO coils likely did not go bad at the same time.
The ECU simply isn't triggering them, because...
Still wondering why I don't get current to the coils - I would think that the coils are normally charged ( with key on ) and the ecu , via the CPS, would cut power for the spark, no? I visualize the CPS/ECU doing the job that points did.
Partially agreed, yes, the trigger signal is ground by the ECU.
No it is not designed to be powered all the time key on/engine off.
See wiring diagram (and/or service manual):
https://www.thisoldtractor.com/mg_manuals/wiring_diagram_v7-iii-e4-stone.pdf
Power supply is 12 V - Red/Brown wire FROM the Injection Load Relay.
Ground is Orange/White (left coil) or Orange/Red (right coil) wire - both go to the ECU
I'm a little confused about what the third wire on the right coil does - "Power Ground 2" according to service manual - Blue wire (also goes to ECU).
Anyway the Red/Brown wire appears to power a bunch of things (both coils, both injectors, fuel pump, and both O2 sensors, presumably the heater circuits). BUT it only does so when the injection load relay is activated, and then it is providing power directly from the regulator/rectifier.
Which suggests you'll only see power to the coils when CRANKING or RUNNING.
At least that's what I'm reading.
Let me know if you still don't have the service manuals for the V7III. The link to a readable diagram is above.
Kev
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Kev - When I back probe the red/brown wire on the coil connector I get a small voltage - like .05 when cranking ( maybe a bad probe contact) - but ya your right, it only powers up when cranking (or running)
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Kev - When I back probe the red/brown wire on the coil connector I get a small voltage - like .05 when cranking ( maybe a bad probe contact) - but ya your right, it only powers up when cranking (or running)
Well that comes from the Reg/Rectifier - which in turn gets power from the stator. So, I wonder if it's time to check the stator coils?
There have been a number of V7III's that burned their stators internally with shorts. Which would drop output to nothing or close to nothing.
The whole system sorta shuts down if it's not getting power when the crank is spinning.
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Kev - When I back probe the red/brown wire on the coil connector I get a small voltage - like .05 when cranking ( maybe a bad probe contact) - but ya your right, it only powers up when cranking (or running)
Just checking in - anymore progress?
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Kev I just got the new cps - it measures 924 ohms - a bit more than what's specified in the service manual 680 +- 15%(102). Should this be a concern? I can't find any independent resistance info on this sensor- Bosch 0261210 (same as the old one). Maybe the sensors changed since the manual was written?
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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
Thats what I would be looking at
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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
Thats where I would be looking, the sensor signals the ECU to fire up the coils, injectors and fuel pump, attach a small lamp to the injection relay contact.
The timing sensor is not a Hall Effect like the ABS Sensors its a very simple coil wrapped around a magnet should measure ~680 Ohms
Its a spare you should have, the motor is dead without it.
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All the sensor does is pick up a gap in the teeth on the tone wheel which triggers the ecu to send signal to the coils.
I doubt both coils went bad at same time.
If there is no power to the coils it indicates the sensor is not sending pulses and the ECU is not turning on the power to the coils and injectors.
I installed an LED on the Injection relay the first change I got. The gap between the sensor and phonic wheel is also very important, I measure that by placing a blob of epoxy or JB Weld on the probe tip then bolting the sensor in place. After allowing time for the epoxy to set you cn take the sensor out again and measure the thickness of the epoxy with vernier callipers to get the gap setting.
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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?
This document describes the sensor on page 13, also shows the gap setting
http://www.dpguzzi.com/efiman.pdf
https://www.thisoldtractor.com/guzzi007/schematics/2015_V7_II_Racer_ABS,_V7_II_Special_ABS,_V7_II_Stone_ABS.gif
The crank position sensor sends pulses to the ECU, the ECU use these pulses to trigger the sparks and the injectors
When the ECU is missing these timing pulses it turns off the injection relay to turn off injectors and coils.
A great aid in troubleshooting is a lamp monitoring the relay, I add one to all my injected Guzzi's (pin 1 - pin 2 of the fuel pump connector in this case.)
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Kiwi - Thanks so much for your help - the cps looks clean although the gear ring does look a little offset from the hole - like Smithswede mentioned - did that ever get resolved? Air gap looks good. The reason i got a new cps is that my old one measured open. I'm just wondering now why my new one measures 924 ohms and not 680? I do notice there's different types of cps on the Guzzis, mine mounts with one bolt where I see that others, I assume on older bikes, mount with 2 bolts - maybe the resistance changed with the upgrades? I really like the idea of that relay light, is there a picture of how you did that? Thank you for that pdf - great info! You're right Guzzis are making us into electricians
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Sorry, late to the party today. Though I don't have the data to say whether or not you should doubt the new part for sure, I kinda feel it's more likely the impedance of the meter is different and the new one is probably good.
That said, I'm still curious if the issue isn't the CPS signal but possibly the stator not providing voltage for the coils. I thought the diagram suggested that the ECU only gets involved when breaking the ground to trigger the coil, but the power to the primary side came from the stator. No?
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That said, I'm still curious if the issue isn't the CPS signal but possibly the stator not providing voltage for the coils. I thought the diagram suggested that the ECU only gets involved when breaking the ground to trigger the coil, but the power to the primary side came from the stator. No?
And THIS is why I was asking if the plugs were wet or dry................ .
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And THIS is why I was asking if the plugs were wet or dry................ .
And again, I'm pretty sure they would have been dry either way.
No current to plugs and injectors = dry
No CPS signal = dry
If I'm reading the WD correctly the injectors can't pulse if the plugs can't fire, but I also believe the ECU WON'T pulse the injectors if it doesn't get a signal from the CPS.
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And again, I'm pretty sure they would have been dry either way.
No current to plugs and injectors = dry
No CPS signal = dry
If I'm reading the WD correctly the injectors can't pulse if the plugs can't fire, but I also believe the ECU WON'T pulse the injectors if it doesn't get a signal from the CPS.
Right, so if plugs were wet, it would likely be more in the power to coils, and less the sensor. That's all I was saying.
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Pretty sure the plugs were dry, bone dry now
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Right, so if plugs were wet, it would likely be more in the power to coils, and less the sensor. That's all I was saying.
I'm not 100% sure but I don't THINK so.
If the sensor fails the ECU will not provide ground to pulse the injectors OR fire the coils. So even if the fuel pump runs while priming and cranking, no pulsing of injectors = no fuel spray.
Since both ignition timing and fuel injection timing is controlled specifically based on engine rpm, no rpm signal because of a bad CKP would mean the ECU wouldn't try to activate either.
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SUCCESS! the bike runs...... it was the cps after all. Bugs me that it would fail so soon (<4k mi). I'll be carrying a spare and a 10 mm socket in my back pack from now on.. Thank you guys for your guidance!
I'd like to see that Kiwi light.
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SUCCESS! the bike runs...... it was the cps after all. Bugs me that it would fail so soon (<4k mi). I'll be carrying a spare and a 10 mm socket in my back pack from now on.. Thank you guys for your guidance!
I'd like to see that Kiwi light.
:thumb:. :thumb:. :thumb:
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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 crank sensor tells the ECU to power up the ignition coils and Injectors
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SUCCESS! the bike runs...... it was the cps after all. Bugs me that it would fail so soon (<4k mi). I'll be carrying a spare and a 10 mm socket in my back pack from now on.. Thank you guys for your guidance!
I'd like to see that Kiwi light.
Here you go, 3 lights, one for each relay under the tank, Start Relay, Injection Relay, Headlight Relay
[img width= height= alt=DSCN0506" border="0]https://i.ibb.co/Z8MX0JZ/DSCN0506.jpg[/img] (https://ibb.co/Z8MX0JZ)
I use type 194 miniature 12V wedge base lamps and solder the wires directly onto the base
https://www.superbrightleds.com/led-light-bulbs-universal-finder/wedge-base-bulbs/194-led-bulb-1-led-miniature-wedge-base
Type 194 have rectifier diodes inside so you dont have to worry about polarity just glue them into a suitable size hole. I also use them to brighten up any old guzzi dash.
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The crank sensor tells the ECU to power up the ignition coils and Injectors
Kiwi, cause you're better at this stuff than me. Is that REALLY what the V7III W/D says?
Sure looked to me like the stator will apply power to both anytime the engine is cranking (and only when the engine is cranking) and the ECU only applies ground (which I know if just two ways around a square and defacto applying ground "powers" up a circuit that is otherwise not powered because of lack of ground, so maybe semantics. But I'm curious if I'm reading that diagram correctly.
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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.
I don't believe you will see power on the coils just because the key is ON
the power to the coils is added when the ECU sees that the motor is turning over (injection relay closed)
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I don't believe you will see power on the coils just because the key is ON
the power to the coils is added when the ECU sees that the motor is turning over (injection relay closed)
Ya I was not getting power to the coil when the cps was busted. Thanks for the pic.