Wildguzzi.com
General Category => General Discussion => Topic started by: jrt on September 26, 2021, 11:33:01 AM
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I have a 2003 EV hydro that won't start. It simply cut out on me driving home- I thought it ran out of gas. So, I put some gas in it, it started, I drove to the gas station, filled it up, started home and it died again. I think I've covered the common issues- I thought it might be the relays, so I ordered new ones from Dan- replaced them all. Checked all the fuses. I have the sidestand leads wired together permanently.
Next, I removed the tank, checked all the connections (there's five big waterproof connectors under the tank). They look fine- no corrosion. Looked for exposed or loose wiring. But- I could not find any connections that might have come loose.
The fuel pump cycles, all electrical devices (horn/signals lights) are working properly. Fuel filter is new.
So now I am wondering if it might be the cam position sensor- I have the three-wire version, and no sensor on the bell housing. After reading these two threads:
https://wildguzzi.com/forum/index.php?topic=101903.0 (Smithswede's V7 wouldn't run)
and
https://wildguzzi.com/forum/index.php?topic=95648.0 (98 EV won't run)
I measured the resistance across the three leads (on the sensor side), but none of them show current- they are all infinite ohms. Should I see 680 ohms across two of the leads?
I don't see gas on the plugs, but it has been a week or two since it has run, so I didn't expect to see anything. I can pull out the sensor as well, but I don't know what I would look for if I did that.
Any other tests I should run while it is apart? I'm thinking maybe I should put the tank back on and try to crank it over, look for spark then check for gas on the plugs? That darn tank is heavy when it is full of gas.
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It has the external fuel pump and filter. Actually, I'm using a big-ass filter from a Subaru (don't judge me!) and it has less than 200 miles on it. The 'new' tank I'm using was clean, the petcock (manual) flows just fine. The throttle bodies are connected, the injectors have pressure (I had to tighten up the clamp to stop a leak on one side).
The sockets for the relays and fuses look good- very little oxidation. There may be a wire that's come loose under one of them, but I'm not seeing it yet. One old relay did test bad, so that's what I initially thought it was. I'll have another look at the sockets.
I'll squirt some starter fluid in the intake...it might be next week before I get to the point where I can do that (work sucks!). It is a good suggestion.
I will continue to follow up and post a resolution when I get it sorted. Now, where did I put my electric hammer?
Thank you
JRT
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Yes. You should see about 680 ohms across two of the wires. (One of the wires is just a sheathing that is grounded to minimize radio wave interference.
At least on the V7, the tell tale sign of no cam phase signal is that you get BOTH an absence of spark, and an absence of fuel.
I think my problem was a bad connector on the cam phase sensor wire. It looked ok, but didn’t work. Letting some Craig De-Oxit sit on it for a good while fixed it.
FYI, you can get new ones much cheaper than stock Guzzi parts. Lots were used on Fiats. Just need to figure out the cross reference
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Yes you need to know if the timing sensor is working.
https://www.thisoldtractor.com/guzzi007/schematics/2004_EV_Catalytic.gif
The pump will always prime when you turn the key On, that's just a simple timer inside the ECU turning on relay (50) to do that, nothing at all to do with the rotation sensor.
When you initiate cranking the timing sensor detects the engine rotation and turns On relay (50) again via the ECU so all you need to do is see if the relay is On, a little light bulb on the Red/Black wire, the 87 pin on relay (50) would be a good place to monitor that.
Another thing that will effect the smooth running is the condition of the signal to the ECU relay (52) its quite often less that 12 Volts due to a dirty contact, again a small lamp connected from 85 to 86 of the relay will monitor that.
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I've had it happen twice on 98-EV. Front timing sensor. First time it was dirty contacts in the connector plug up under the tank. Second time it was due to an open/broken wire. Had to replace the sensor.
Patrick Hayes
Fremont CA
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General question:
I have much more automotive FI diagnosis experience than with cycles. With automotive FI, since 1996, the ECU stores error codes for any circuit-related problems.
Don't motorcycle ECUs store problem codes?
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General question:
I have much more automotive FI diagnosis experience than with cycles. With automotive FI, since 1996, the ECU stores error codes for any circuit-related problems.
Don't motorcycle ECUs store problem codes?
Sure they do but how to read them? (I do know the answer you will give me)
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I measured the resistance across the three leads (on the sensor side), but none of them show current- they are all infinite ohms. Should I see 680 ohms across two of the leads?
Yes as SmithSwede says the sensor should read about 680 Ohms. The sensor known as a Variable Reluctance Sensor, is a coil of wire wound around a tiny magnet. The magnet projects a small magnetic field that is influenced by the teeth of the Phonic wheel passing by, the small disturbances in the field are converted to a low level AC Voltage.
Of course if the coil is open circuit or the two pin connector is dirty this tiny AC Voltage cannot get through to the ECU.
Because the signal from the sensor is so weak its very important that the gap between the sensor and the Phonic wheel teeth is not too great, sometimes an owner will add an "O" ring to stop the oil leak making the gap too great. Read about this sensor in this old but very informative document http://www.dpguzzi.com/efiman.pdf page 12 & 13, it gives the gap as 0.6 - 1.2 mm. It would be simple to measure this gap with feeler gauges however the gap is normally inaccessible, I check the setting by removing the sensor to stick a blob of something on the tip, bolt it back in place then wait for it to set up (I use JBQuick). Once its set up you can remove the sensor again and measure the thickness of the blob with a vernier caliper.
The sensor comes with a cable about a foot long so looking under the tank you will find the mating socket, inspect it closely for any sign of corrosion whatsoever, it must be pristine.
The colour plate on page 2 shows two sensors 7 & 8, you can see the socket nearby, later motors only have 1 sensor with a Phonic wheel on the camshaft. One tooth is missing from the phonic wheel, the ECU uses the extra gap as home position and counts from there to establish its place in the cycle.
When you turn the key On the motor is not turning over of course so the reluctance sensor is not producing any signal, a simple timer in the ECU starts the pump for the priming cycle pulling output Pin 2 to ground turning on the injection relay (50), powering up the two coils, two injectors and the fuel pump a couple of seconds later the timer releases pin 2 and the ECU waits for the sensor to pickup rotation.
Note I will refer to the 15M ECU pin numbers in this description but read the document referring to the diagram at the end for a P8 ECU, understand this and you have the basis of fuel injection.
(https://i.ibb.co/dJTR3R9/DSCN0975.jpg) (https://ibb.co/2Y9TLT2)
I added this sketch showing how you can use LEDs as the lights the resistor limits the current to the LED so it doesn't burn out, A 12 Volt LED has a resistor built in.
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Thanks for the replies- SS, KR, Pat- I must have had my multimeter set incorrectly (or a lead in the voltage instead of ohms). I went back and checked the cam sensor again and it reads 700 ohms across the + and -. I 'jiggled' the wires around- no change and the wire feels normal- so I don't think it is a broken lead. I sprayed contact cleaner in the junction block- both sides. It looks really good though. I don't think this bike saw a lot of weather. The wiring diagram from Carl Allison (and what I found on the web) suggests that the shield wire and ground should be connected- no resistance or is there a diode?
Tonight, I'll pull the sensor out of the timing cover to inspect it. It has a very slight weep of oil, so the o-ring should be changed out anyway. Roy, I cannot think of how the gap between sensor and timing wheel could have changed, but anything is possible at this point. After I get an o-ring, I'll start to put it back together- I've got the wiring harness pulled out from the frame, so I'll need to dress it back in.
I checked the fuse and relay sockets and they look ok- all the relays are getting 12V on the 30 pin...I know it doesn't mean they all work, but the relays are new. Roy, I'll make up some test lamps for the relays as you suggest. Do you use LED's for that?
Once I get the tank on and gas hooked back up, I'll also try Roadkyll's suggestions and check for spark.
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Feel free to give the connectors more contact cleaner. I “cleaned” mine several times and it looked fine. But wasn’t. Finally got it clean enough to work.
You may have some metal crap built up on the head of the sensor. Clean that off.
I’m told there are fairly cheap meters ($60) that can read the output of a working sensor. I don’t think you can tell anything with a voltmeter.
FYI, the oil is likely leaking *through* the sensor, not from the O ring. The fix is to use some of that locktite sealant on the face of the sensor itself so it soaks into the unit. These sensors are not meant to be used in a wet oil environment but Guzzi does it anyway. So they leak oil.
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Roy, that’s a brilliant chart. Thanks ! I really need to get mine rigged up like this.
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Great chart, Roy- thank you!
Thanks SmithSwede- I'll do that.
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Thanks for all your comments- they were very helpful and I think (maybe) I have this figured out.
The wiring diagram, comments about the sensor and some reading on the EFI document were very helpful, so thanks for all that. I made some LEDs and hooked them to the pins as Roy suggested and the ignition (52) stayed lit while the pump/injector/coils (relay 50, pin 87) flashed, cycled the pump then went off. The injector relay (50) LED would not come back on when I turned the motor over. Both went out as expected when the kill switch was turned off.
I also checked the plugs (dry) and sprayed a bit of starter in the intake (nothing).
So, I cleaned and cleaned the connections, measured and remeasured the resistance of the sensor- all good.
Then, when I took the sensor out for the second time, I noticed that one of the cogs was dead nuts on center in the hole. So, I used my depth gauge to measure the distance between the machined face of the block and the tooth, and a vernier to measure the sensor reach- they gave a difference of 2.3-2.6 mm.
The sensor had two shims- one thick and one thin and an o-ring. I removed the thinner 0.6 mm shim, put it all back together and it fired up on the first revolution.
But! It was running fine a month ago! Did someone break into my house and put an extra shim in the phase sensor as a practical joke? Did my crankshaft shrink? Aliens? :shocked:
Well, I'll take it out for a short ride tomorrow- I have some more parts to take care of.
Thanks, ya'll.
JRT
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Make sure you take your phone! Stuff shrank overnight, it's the lil people.
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'Twas the Keebler Elves , they be wicked little devils .
Dusty
You got 'em over there too Dusty?
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Thanks for all your comments- they were very helpful and I think (maybe) I have this figured out.
The wiring diagram, comments about the sensor and some reading on the EFI document were very helpful, so thanks for all that. I made some LEDs and hooked them to the pins as Roy suggested and the ignition (52) stayed lit while the pump/injector/coils (relay 50, pin 87) flashed, cycled the pump then went off. The injector relay (50) LED would not come back on when I turned the motor over. Both went out as expected when the kill switch was turned off.
So it was just too much gap then, I don't think they come with an "O" ring but when it leaks oil the logical solution is to put one on, Im glad the tell-tail light worked out for you, as I said before the pump will always prime because it doesn't rely on the sensor for that, the motors not even turning. I would leave the lights in place, they don't do any harm just put on a light show.
FYI, the oil is likely leaking *through* the sensor, not from the O ring. The fix is to use some of that locktite sealant on the face of the sensor itself so it soaks into the unit. These sensors are not meant to be used in a wet oil environment but Guzzi does it anyway. So they leak oil.
I often suspected that was the case, I've had experience with industrial sensors like that. the hard epoxy doesn't stick to the magnet or the soft cable coming out the back end, Oil doesn't hurt the internals, just makes a mess when it leaks back out the cable side.
Its a similar situation with the Guzzi ABS sensors the gap between the epoxy and the soft cable wicks water right inside to corrode/short out the connections, some silicone sealant applied is able to stick to the epoxy and the cable to form a flexible seal, if you have a later bike with ABS and ride in the rain attend to those.
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Thanks for all your comments- they were very helpful and I think (maybe) I have this figured out.
The wiring diagram, comments about the sensor and some reading on the EFI document were very helpful, so thanks for all that. I made some LEDs and hooked them to the pins as Roy suggested and the ignition (52) stayed lit while the pump/injector/coils (relay 50, pin 87) flashed, cycled the pump then went off. The injector relay (50) LED would not come back on when I turned the motor over. Both went out as expected when the kill switch was turned off.
I also checked the plugs (dry) and sprayed a bit of starter in the intake (nothing).
So, I cleaned and cleaned the connections, measured and remeasured the resistance of the sensor- all good.
Then, when I took the sensor out for the second time, I noticed that one of the cogs was dead nuts on center in the hole. So, I used my depth gauge to measure the distance between the machined face of the block and the tooth, and a vernier to measure the sensor reach- they gave a difference of 2.3-2.6 mm.
The sensor had two shims- one thick and one thin and an o-ring. I removed the thinner 0.6 mm shim, put it all back together and it fired up on the first revolution.
But! It was running fine a month ago! Did someone break into my house and put an extra shim in the phase sensor as a practical joke? Did my crankshaft shrink? Aliens? :shocked:
Well, I'll take it out for a short ride tomorrow- I have some more parts to take care of.
Thanks, ya'll.
JRT
The sensor gap should be .7-.9mm. Your sensor set at 2.3-2.6 is miles away from spec and probably on the upper limit of what the sensor will tolerate. Only a tiny degradation in sensor capacity and it's no start. I'd set it to the correct gap myself as its now probably still to wide for reliability and good running. .
Ciao
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Yeah , the little bastiges are everywhere , they get in your hair , in your clothes hamper , everywhere . During their rut you can't go anywhere W/O shooing them off the roads , a mating pair has taken up residence in our utility closet , won't even go into the trauma that is causing our cat .
Dusty
The brastards ran off with one of of my rubber cushes from the rear drive. Had six, straight in to a tray, didn't move my position but now only 5. Gutted the garage. Gone. Had to order in another one. Brastards. :evil: :evil:
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Bruce is the only person I know that has been able to put the little fellers to good use, making gaskets.
https://www.thisoldtractor.com/moto_guzzi_loopframe_petcock_gasket_kit.html
Roy, I did leave the LEDs in place, but I cannot see them under the side cover (doh!).
There is a stepped edge on engine block- sure looks like an o-ring goes there. The oil is definitely coming from inside the sensor, so SmithSwede's assessment is correct- a new o-ring aint gonna help.
Phil- I'll probably mess around with the sensor gap as I obsess about the oil leak! Right now, I just want to drive it to work- no long trips.
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Well, it did it again. It's something intermittent that I haven't found. Maybe a broken wire? I cannot feel it if it is. Maybe the kill switch? But the computer is still getting power, so I don't think so.
It didn't start this morning when I was going to take it for a ride, so I pulled the sensor out....again....and there was a very small amount of swarf on it- so I cleaned it. Measured again- it is 29.0 +/- .1 mm from the exterior block surface to the phonic wheel. The sensor...I think it is 29.4 mm or so, so it definitely needs a spacer.
Put it back together and it fired right up. So I drove it around the block. Parked. Then it didn't start. Then the next try it did. G**d**n gremlins.
Anyone know where to get a Magneti SEN 8I3? I looked, but cannot find one.
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This might not be of much help, but...
You messed with the sensor. That means you messed with the wires. Maybe there is a bad connection? Next time it doesn't start. Wiggle the sensor wire, turn the bars, ect..
I'm also assuming that by it didn't start, you mean it just cranked all you wanted but did not start/run. Right?
Tom
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This might not be of much help, but...
You messed with the sensor. That means you messed with the wires. Maybe there is a bad connection? Next time it doesn't start. Wiggle the sensor wire, turn the bars, ect..
I'm also assuming that by it didn't start, you mean it just cranked all you wanted but did not start/run. Right?
Tom
Correct- I did wiggle any wire I could get a hold of, moved the bars, cycled the kill switch. None of that helped. With Roy's LEDs in place you can monitor whether the sensor (and ECU) pick up the rotation of the crankshaft. It did not pick up rotation- that is, the ECU never turned on the coils/injectors/pump when I was turning the motor over. So, I'm back to thinking that either the sensor is dying some weird slow death, or there is a broken wire somewhere in the harness. It is a bit frustrating.
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Could be a bad sensor? A friend that rides HD, carried a spare crank position sensor. On a few long distance rides, someone would have one fail. At least on HD, the sensor fit the hole of many models, but you may have to cut and splice the wires.
I'm pretty sure the sensor is from a car, just don't remember which. Hopefully someone will come along with a part number.
EDIT: I'm sure you've tried removing a spark plug lead and plugging in a known good plug and grounding it to the head to see what happens when it's in no run mode?
Good luck!!!!
Tom
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Well, it did it again. It's something intermittent that I haven't found. Maybe a broken wire? I cannot feel it if it is. Maybe the kill switch? But the computer is still getting power, so I don't think so.
It didn't start this morning when I was going to take it for a ride, so I pulled the sensor out....again....and there was a very small amount of swarf on it- so I cleaned it. Measured again- it is 29.0 +/- .1 mm from the exterior block surface to the phonic wheel. The sensor...I think it is 29.4 mm or so, so it definitely needs a spacer.
Put it back together and it fired right up. So I drove it around the block. Parked. Then it didn't start. Then the next try it did. G**d**n gremlins.
Anyone know where to get a Magneti SEN 8I3? I looked, but cannot find one.
So what was your handy dandy LED telling you while this was going on? Never mind you said it wasn't coming on.
I never had any luck trying to measure the depth and subtracting the length, try my method with JB Quick or other fast setting substance, stick a blob to the tip then bolt it in place with a tooth centred in the hole.
After it's had time to set=up remove it again and measure the thickness of the blob with a vernier caliper. The JB Quick will not stick to the cog because it has a film of oil on it.
http://www.dpguzzi.com/efiman.pdf Page 12/13
The gap should be 0.6 - 1.2 mm
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Well, it did it again. It's something intermittent that I haven't found. Maybe a broken wire? I cannot feel it if it is. Maybe the kill switch? But the computer is still getting power, so I don't think so.
It didn't start this morning when I was going to take it for a ride, so I pulled the sensor out....again....and there was a very small amount of swarf on it- so I cleaned it. Measured again- it is 29.0 +/- .1 mm from the exterior block surface to the phonic wheel. The sensor...I think it is 29.4 mm or so, so it definitely needs a spacer.
Put it back together and it fired right up. So I drove it around the block. Parked. Then it didn't start. Then the next try it did. G**d**n gremlins.
Anyone know where to get a Magneti SEN 8I3? I looked, but cannot find one.
Ebay for like $40usd. They are a common sensor. I bought 2 direct from China who are the only ones that still make them these days I think for $10usd each. You can still buy the oem old stock for $175usd I think but the Chinese ones look high quality and have worked totally fine on my engine. I only bought 2 because the shipping was $15usd at the time for 1 and the same for 2 so I bought a spare. The $40 ones will be the same Chinese repros as mine.
Ciao
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So what was your handy dandy LED telling you while this was going on?
I never had any luck trying to measure the depth and subtracting the length, try my method with JB Quick or other fast setting substance, stick a blob to the tip then bolt it in place with a tooth centred in the hole.
After it's had time to set=up remove it again and measure the thickness of the blob with a vernier caliper. The JB Quick will not stick to the cog because it has a film of oil on it.
http://www.dpguzzi.com/efiman.pdf Page 12/13
The gap should be 0.6 - 1.2 mm
Or you can use one of these or make one and get it accurate without the risk of JB weld or plasticine dropping in the engine.
Ciao
(https://i.ibb.co/BT2LmD9/86d9632d5d2b208d6bdfe9178a9c6044-1.jpg) (https://ibb.co/BT2LmD9)
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Or you can use one of these or make one and get it accurate without the risk of JB weld or plasticine dropping in the engine.
Ciao
(https://i.ibb.co/BT2LmD9/86d9632d5d2b208d6bdfe9178a9c6044-1.jpg) (https://ibb.co/BT2LmD9)
That is a nice solution for someone who has access to a lathe, I offer my solution as a simple one that is quite safe if you take reasonable care.
I have had bad experience with Chinese parts on my Guzzi.
Alternator, Wheel bearings, Condenser failed almost from the start.
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Modeling clay works to measure gaps, too.
Could this be temperature related?
Could it be a coil failure?
The thought occurred to me. If it were a coil failure, the LED that indicates power to the pump/coils/injectors (50) would be lit. And there are two coils...I think, so the chance of them both failing at the same time is slim.
Could be temperature related but I'm skeptical about that as well. It is not simple hot/cold. It didn't start when it was cold, then it did, ran for a bit, started when it was warm, then it didn't.
I also considered low battery voltage, but I've kept it (Odyssey PC480) on a charger. The starter works just fine and the voltage output on the bike above 2000 rpm is 13.7-13.8 V.
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Ebay for like $40usd. They are a common sensor. I bought 2 direct from China who are the only ones that still make them these days I think for $10usd each. You can still buy the oem old stock for $175usd I think but the Chinese ones look high quality and have worked totally fine on my engine. I only bought 2 because the shipping was $15usd at the time for 1 and the same for 2 so I bought a spare. The $40 ones will be the same Chinese repros as mine.
Ciao
Thanks- I'll look into that. I tried various auto parts stores online, but found nothing.
And...I'll have to make up a tool like you posted. I like that kind of thing.
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The thought occurred to me. If it were a coil failure, the LED that indicates power to the pump/coils/injectors (50) would be lit. And there are two coils...I think, so the chance of them both failing at the same time is slim.
Now you're starting to think like a sparky
Thanks- I'll look into that. I tried various auto parts stores online, but found nothing.
And...I'll have to make up a tool like you posted. I like that kind of thing.
For the non-lathe owners how about just tapping a small piece of flat material with a screw through it (c/w locknut) to touch the phonic wheel then it would be a simple matter of holding it against the sensor to see the gap. I thought about having a light to show when the wheel was contacted but that's over thinking.
The light on the 52 relay must be fully lit also, I have seen mine flickering at ~50% when the stand switch was faulty.
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Now you're starting to think like a sparky
Aw, that's nice. Made my day.
The light on the 52 relay must be fully lit also, I have seen mine flickering at ~50% when the stand switch was faulty.
Fully lit when running.
I'm going to wait until a new sensor arrives from Latvia- probably late this month. I'll update then.
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FYI, I got my sensor cheap from Elbonia. Like $20. It was a little muddy, but has worked fine now for 50,000 miles.
I’m still betting grotty connectors or simply a bad sensor. Yes, the air gap is important, but if it worked before, I don’t see how that can be the issue since the gap can’t change. Unless you did something immediately before the failure like add an O ring.
I’m assuming you tried tightening the screws that hold the sensor in place.
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FYI, I got my sensor cheap from Elbonia. Like $20. It was a little muddy, but has worked fine now for 50,000 miles.
I’m still betting grotty connectors or simply a bad sensor. Yes, the air gap is important, but if it worked before, I don’t see how that can be the issue since the gap can’t change. Unless you did something immediately before the failure like add an O ring.
I’m assuming you tried tightening the screws that hold the sensor in place.
I didn't touch the sensor, the screws...nothing before this happened. I can see clear, shiny metal lines on the connectors. I'm guessing it is the sensor also, but I won't know for sure until I replace it. Right now, my theories are: oil incursion has somehow damaged the electronics, the wires are too close to something else (coils) so I'm getting interference or there is a mystery wire broken somewhere. Here's hoping my Latvian replacement comes in soon.
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I didn't touch the sensor, the screws...nothing before this happened. I can see clear, shiny metal lines on the connectors. I'm guessing it is the sensor also, but I won't know for sure until I replace it. Right now, my theories are: oil incursion has somehow damaged the electronics, the wires are too close to something else (coils) so I'm getting interference or there is a mystery wire broken somewhere. Here's hoping my Latvian replacement comes in soon.
There's no electronics inside the sensor, its just a coil of fine wire wound over a magnet, my guess would be the wire has parted where it joins to the leads, you could try measuring the resistance while warming it up with a heat gun or hair dryer an open circuit sensor will never run.
You could connect an LED in series and power it from a 6 Volt source while you warm it, a light is a lot more visual than a digital meter.
Another test is to measure the resistance then switch the meter leads around, sometimes if there's any corrosion present it will measure a different resistance as if there was a small battery in circuit (the corrosion forms a small cell)
I have never tried to measure the signal coming from the sensor but I would expect it to increase in amplitude as the distance to the phonic wheel is decreased so run it at a reduced gap.
Did we ever establish which model ECU we are running the old P8 with the large Pizza box or smaller 15M?
For a little light entertainment while waiting on your new sensor visit the MyECU site by Cliff Jefferies https://www.myecu.biz/MyECU/index.htm
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I'll give the heat gun a try... interesting point about hooking the leads up reverse.
The ECU is a 15M. I remember when Cliff Jeffries started his myECU project- I think it was for an 1100 sport? The good folks at V11LeMans got very interested in it (I had a V11 sport at the time). That's above my pay grade- I've made tube (valve) amplifiers and some stereo gear, but that's about it.
Cheers,
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I'll give the heat gun a try... interesting point about hooking the leads up reverse.
The ECU is a 15M. I remember when Cliff Jeffries started his myECU project- I think it was for an 1100 sport? The good folks at V11LeMans got very interested in it (I had a V11 sport at the time). That's above my pay grade- I've made tube (valve) amplifiers and some stereo gear, but that's about it.
Cheers,
Yes, I put one of Cliff's kits together for my VII Sport, I got one of the gurus to send me a copy of his map, worked very well.
His site used to have a very good description of how the ECU worked broken down into the various systems.
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I can confirm Roy is correct. The sensor is just a metal spike with a thin wire wrapped around it, all covered in plastic. I took a Dremel to one because I wanted to know for sure what the thing was.
There are only 2 active wires—one going into the coil and one going out. So this is a 2 wire sensor, not a 3 wire sensor.
But it does have a 3rd wire. The third wire just attaches to a foil sheath that surrounds the two wires. I’m sure to cut down on RF interference, and ground on the bike.
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The third wire just attaches to a foil sheath that surrounds the two wires. I’m sure to cut down on RF interference, and ground on the bike.
That's good to know because (if I recall correctly) there was not any conduction between the S pin and the (-) pin.
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OK, now I know a lot more about variable reluctance sensors than I ever thought I would know. But thanks to the good folks here, I also learned a lot about electronic engine management. I still have a ways to go... :)
So- where I'm at on my bike is that I ordered a new crankshaft position sensor (from Latvia!) and installed it. Bike fired up on the first turnover and seems to be running just fine. I had it out for about 40 miles, got it good and hot (warmed up). It never skipped a beat.
I made this depth tool out of (black) acetal rod and an aluminum rod. The aluminum fits in the plastic with a tight friction fit and the plastic rod sits in/on the hole in the block. Took me longer to type those sentences than to measure the depth. If anyone wants to use it, send me a note-I'm happy to loan it out.
(https://i.ibb.co/zRjnhv6/IMG-6257.jpg)
I rigged up my oscilloscope to try and measure the output from the old sensor, but I couldn't get a reading from it at all. I spun a driveshaft in my lathe (hey, it has teeth!), applied a voltage to the sensor and tried to get a signal from the "S" wire. Actually, I tried every combination- nothing. I managed to pick up 60 Hz from the house electricity... I was too hasty and installed the new CPS without trying it, but I ordered a second one as a backup, so I'll test it when it gets in.
Here's the bike-
(https://i.ibb.co/sFCTwPS/IMG-6259.jpg)
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I’m a shyster, not a sparky, so take everything I say with a grain of salt. I do not think this sensor is a genuine 3 wire or Hall effect sensor. (That is confusing because it really does have three wires not two, but the third wire is actually a foil sheath that grounds and minimizes RF interference).
In other words, this is not a sensor that takes a 12v current through 2 of the wires, and then outputs a signal on the third wire. Instead, it is simply a permanent magnet with a wire coil wrapped around it. It does not receive 12 v from the vehicle. It instead outputs some voltage that is induced into the coil as a metal piece passes into, and then out of, the magnetic field created by the permanent magnet.
So to test your old one, I think you would simply hook a scope to the two wires of the coil, pass metal close to the sensor, and see if you get an output voltage. I don’t think you would apply current to the two wires—where would the signal go since the “third” wire is grounded?
Of course, you could easily test my assertion by seeing if there is a current being supplied to the sensor at the connector, or if the connector is simply collecting a (weak) current by inductance. If the engine works with the new sensor, and is not receiving any input voltage from the connector, it really is just a 2 wire sensor (with 3 wires) as opposed to a genuine Hall effect or 3 wire sensor.
I never checked mine. Once it started to work again, I stopped messing with it.
If I were you, I would try swapping the original sensor back onto the bike. If the engine never works with the old sensor, and always works with the new sensor, you can be confident that the sensor was the problem (as opposed to flaky wiring, etc.). If the bike now works even with the old sensor, then it never was the sensor, but was instead a bad connector, something with air gap, or another issue.
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I don’t really trust these sensors anymore. And if one fails, you aren’t moving. I highly recommend keeping a known good sensor stashed under your seat somewhere. They are small, light, cheap, but mission critical.
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Have a buddy looking for source of that sensor. Please post link/info of where you purchased it.
Thanks
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I don’t really trust these sensors anymore. And if one fails, you aren’t moving. I highly recommend keeping a known good sensor stashed under your seat somewhere. They are small, light, cheap, but mission critical.
I tend to agree with this, when I had a VII Sport I carried a spare, I don't have one for my V7 however I can be certain that the dealer doesn't have one either and it will be several weeks away.
Please include a link to the ones you have found.
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If I ever have one of those bikes again the first thing I buy will be a spare sensor,had them fail on 2 different bikes,no advance warning,cheap insurance.
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This is the one I bought:
https://www.amazon.com/gp/product/B00D76FWF2/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
I think these folks sell on ebay as well. They are in Latvia.
I'm sure it can found cheaper, but for 30 bucks...I already wasted that much in time. I got this one, it looks ok...so I bought a spare. It is slightly longer than the one that came out of the bike, so measure!!
SSwede- you might be right about the sensor not being a true Hall effect. I don't know- the wiring on the loom for the 'S' lead does go to ground, so that supports your statement (that it is just a shield). I tried pretty much every combination of oscilloscope on the sensor and never got a signal out of it. I might put it back in...but that involves removing the tank again. Twice. I'm going to wait until my spare arrives, then see if I can get a signal out that. I'm inertial in that regards.
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Thank you so much for the info as to source. Will pass on to bud as well as clearance install
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SSwede- you might be right about the sensor not being a true Hall effect. I don't know- the wiring on the loom for the 'S' lead does go to ground, so that supports your statement (that it is just a shield). I tried pretty much every combination of oscilloscope on the sensor and never got a signal out of it. I might put it back in...but that involves removing the tank again. Twice. I'm going to wait until my spare arrives, then see if I can get a signal out that. I'm inertial in that regards.
My curiosity got the better of me so I went and measured the signal on my V7, the sensor measured 895 Ohms and it put out about half a Volt AC p-p while cranking, measured with my multimeter. I also hung the oscilloscope on it, quite a regular looking sine wave at about 100 Hz
The V7 is different to the old style one you picture, just one fixing screw but a similar cable and flat 3 pin connector, I wouldn't be surprised if they would work at a pinch.
If your old sensor is open circuit it's game over and yes the third wire is just a shield.
The odometer needs a Hall Effect so it doesn't miss any pulses, that type of sensor will switch at any speed right down to zero.
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One interesting thing, with the sensor unplugged the motor would turn over for a couple of seconds, pause then try again without start button input as long as the key was left on.
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Thanks Roy, that’s what I thought. My theory is that this little 1/2 volt signal requires excellent connectors or the engine won’t run. Which is why mine didn’t run even though I thought I had cleaned the connector and contact was good.
What I don’t understand is why they fail. Very simple little coil, so why would they crap out in only 30 to 60K miles?
I’ve been told that these were originally designed for the dry side of some Fiat engine. Guzzi perversely uses them on the wet side of the engine, so they get doused in oil they were never designed to resist. So does the hot oil get in there somehow and promote premature failure?
I think there is some kind of Locktite wicking sealant you can apply to the inner face of the sensor that would soak in and make the unit oil proof. If I have to replace another one, I’m going to give the new one the Locktite treatment.
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In my experience coils often fail at the solder joint where the coil is soldered to the leads, i'm not sure why, perhaps it's the corrosive nature of the solder flux or some differential expansion thing.
I used to find a lot of transformers would go open circuit where the stranded copper wire was joined to the winding.
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SmithSwede
Do you have a source of the cam sensor for our V7s?
Never mind I ordered a pair for $10 ea off fleabay.
https://www.ebay.com/itm/Crankshaft-Position-Sensor-For-FIAT-FIORINO-TEMPRA-SW-TIPO-PREMIO-LANCIA-7756925/323257492542
I know, I know I said no more Chinese parts.
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In my experience coils often fail at the solder joint where the coil is soldered to the leads, i'm not sure why, perhaps it's the corrosive nature of the solder flux or some differential expansion thing.
I used to find a lot of transformers would go open circuit where the stranded copper wire was joined to the winding.
Maybe- the wires are very stiff near the sensor end, much more supple near the plug...it may have cooked something? Bike doesn't seem to run too hot, so maybe some combo of oil and heat?
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Late to this party, and likely just as well as it seems resolved and, besides, as many here know, my own contributions to automotive-electric discussions are below zero.
Naturally, that won't stop me from saying something. :shocked:
My EV suffered some years ago from a similar problem. Eventually stranded me hundreds of miles from home. A Guzzi dealer gave up on it. Guzzi Guru Wayne Orwig figured it out!
Corroded ignition switch.
I now use "products" to clean my Guzzis and only rarely wash them with water.
May have no application to the present problem, but I mention it if the issue recurs.
Bill
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SmithSwede
Do you have a source of the cam sensor for our V7s?
Sorry, on the road and away from my receipts. I just did a lot of googling. These are used on a lot of Fiat engines, so search accordingly. There is a huge price difference. I wound up getting two or three from Latvia or Elbonia or someplace. Arrived in a spiffy baby blue box. The one I installed has worked great for 60,000 miles now, and was cheap. Like $35. I think Guzzi wants about $200.
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This conversation about the price of a sensor reminds me of the time my Ducati roasted one its two Bosch ignition modules.
Ducati, Laverda, and Moto Guzzi all used the same module with the same Bosch part number. Ducati wanted over $300 for it, Laverda wanted $250, and Guzzi wanted $125. IIRC, I could have ordered it from the local Beck-Arnley, but it would have taken weeks, if not months, to arrive; I don't remember their price.
Wanna guess where I bought the replacement module?
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Wanna guess where I bought the replacement module?
Latvia?
(jk)