SHIGGSY
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Posts: 128
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posted July 28, 2007 12:26 PM
 Edited By: SHIGGSY on 28 Jul 2007 13:30
Wired my crank sensor the wrong way round
I've been a wally.
Pulled the wires from my crank sensor connection to connect it to an oscilloscope (it was fine) so put it back and went on to the cam sensor. The bike wouldn't start so I thought I'd connected the cam sensor wires wrong and swapped them (I know) and it still wouldn't start. So then I rtfm and the cam sensor was originally correct and I had wired the crank sensor back incorrectly. Put everything right...and it still wouldn't start. No fault codes, fuses all ok (including in the battery compartment).
Any ideas what I have damaged ?
  
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ridgeracer
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posted July 28, 2007 02:03 PM
You can't damage the ECU by connecting either or both of them backwards.
Did you remove the sensors from the bike at all? The gap between the sensors and the timing wheel is important.
Also is there a chance with all this playing around the battery is becoming run down? There is a point were the bike will still crank but the ECU will refuse to fire because of low voltage.
Unlike the injectors the ECU doesn't monitor the sensor circuits for open or short circuit. The way it works is that if it gets so many cam pulses and no crank pulses then it assumes the crank sensor is bad or if it gets so many crank pulses and no cam then it assumes the cam is bad. To get no ECU error code you would have to have both of them not pulsing.
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SHIGGSY
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posted July 28, 2007 03:42 PM
quote:
You can't damage the ECU by connecting either or both of them backwards.
phew
quote:
Did you remove the sensors from the bike at all? The gap between the sensors and the timing wheel is important.
]
nope
quote:
Also is there a chance with all this playing around the battery is becoming run down? There is a point were the bike will still crank but the ECU will refuse to fire because of low voltage.
No thats still ok (i have an inline voltage meter on it)
quote:
Unlike the injectors the ECU doesn't monitor the sensor circuits for open or short circuit. The way it works is that if it gets so many cam pulses and no crank pulses then it assumes the crank sensor is bad or if it gets so many crank pulses and no cam then it assumes the cam is bad. To get no ECU error code you would have to have both of them not pulsing.
Its possible that I have 'blown' both the sensors then ?
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ridgeracer
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posted July 28, 2007 04:00 PM
Blown is not a word that really applies. All these sensors are is an iron core wrapped in copper wire. They are totally passive. They do fail over time. The copper wire is not insulated per say but just covered with a varnish. Over time it heat and vibration can break it down and cause a short. Unless you were pulling on the wires really hard I don't see how you could of damaged them, especially if you didn't take them off the bike.
Have you done a resistance check on them with an ohm meter? You might want to do it at the ecu plug that way your checking the continuity thru the wires, the connectors you were messing with, and sensor.
cam sensor should read 400 ~ 460 ohms
crank 375 ~ 565 ohms
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SHIGGSY
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posted July 29, 2007 03:20 AM
Edited By: SHIGGSY on 29 Jul 2007 04:22
Crank sensors ok but cam sensor is ohming slightly high at 472 (that directly at the sensor not threough the ECU), how significant is that ?
Actually I recall now that even though the crank sensor was wired the wrong way round I did have it running fine before mucking around with the cam sensor, so I'm wondering if wiring these sensor backwards actually has any adverse effect ?
At the moment she turns over healthy, I have sparks and I have fuel getting to the plugs but she won't fire. I'm going to do a top up charge on a spare battery I have and swap batteries incase it's something like a cell gone.
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ridgeracer
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posted July 29, 2007 05:30 AM
Edited By: ridgeracer on 29 Jul 2007 06:34
I would say 472 is with in the error range of your meter, its less than 0.5 % off value.
As for damaging the cam circuit in the ECU. I have taken apart an ECU and traced out the cam and crankshaft sensor circuits.
This is the crank circuit but the cam is similar with some slightly different resistor biasing. There is no way just hooking the sensor up backward is going to damage it. It is designed for an AC signal; a signal that goes both positive and negative with respect to ground. The lines are marked plus and minus but that is only to identify which lead goes positive on timing tab arriving at center vs departing center.
The only way you could of damaged this circuit is if at some point you hooked the cam- lead into the ecu to +12Volts putting too much current thru diode D207.
The one thing you still haven't checked is the wiring all the way to the ECU plug. Maybe you've messed up the connector? Maybe taking the pins in and out of the connector so many times you've messed up the locking tab and when you push the plugs together the pins are being pushed out instead of mating correctly.
Troubleshooting 101; Eliminate the possibilities you can easily test for before theorizing about stuff you can't easily test. In other words it is possible that your significant other sabotaged your bike so you would spend more time with her, but lets check the connection thru the plugs you were messing with first. 
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SHIGGSY
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posted July 29, 2007 05:47 AM
Edited By: SHIGGSY on 29 Jul 2007 06:48
Thanks for reply. The spare battery didn't make any difference. Checked the ohm reading for both sensors back at the ECU and they were both in spec. Went back to the cam sensor and re-checked again, now it' reading in spec. I had the wires out of the connection socket before so it must have been the way I was probing the wire to give the high ohm.
Gawd knows what I have done. Apart form top up charging the first battery and retrying that I'm not sure what my next move is.
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SHIGGSY
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posted July 29, 2007 08:57 AM
Think the cam sensor has had it. Cranked the bike over with a scopemeter on the crank sensor and got regular 4v apprx. Did the same with the cam sensor and flat lined with an occasional blip. I'll replace it and take it from there.
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buddy
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posted July 29, 2007 09:05 AM
If you are getting both fire and fuel, as stated above, I would think there should at least be some popping and sputtering while cranking.
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SHIGGSY
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posted July 29, 2007 10:13 AM
quote:
I would think there should at least be some popping and sputtering while cranking.
Nope nothing, not attempt to fire at all. I can pull the plug and see it's wet and I can crank it and see it sparking and also see the fuel being shot up out of the spark plug hole.
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buddy
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posted July 29, 2007 11:50 AM
Theres only 3 things required for combustion, fuel, heat and air. You've got heat in the spark, air must be in there when the fuel came in so it might be worthwhile to check that the fuel is good.
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rgeorge
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posted July 29, 2007 01:33 PM
quote:
Think the cam sensor has had it. Cranked the bike over with a scopemeter on the crank sensor and got regular 4v apprx. Did the same with the cam sensor and flat lined with an occasional blip. I'll replace it and take it from there.
That sounds normal to me.
The crank sensor signal repeats every 45 deg crank angle. The cam sensor signal only occurs once every 720 deg crank angle.
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SHIGGSY
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Posts: 128
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posted July 29, 2007 01:54 PM
I'll do a 2 channel scan tomorrow and compare it. Thanks for that.
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zx12mark
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posted July 29, 2007 02:22 PM
my cam sensor went bad. i rode the bike one day then the next day it would'nt start.i checked the f.i. codes then replaced the cam sensor.that was say 3 years ago.
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SHIGGSY
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Posts: 128
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posted July 30, 2007 12:25 PM
New cam sensor in and she's running  (I knew it was that....I wasn't scared).
Amazingly the bike shop had one in stock, stuck it in this evening, it started to try and fire immediately, few more coughs and splutters and it fired up. Seems ok on the move but it's developed a bit of a vicious jerky stumble at 2000rpm. I'll see how it goes.
Seems my method of weeding out weak electrical components by wiring up stuff inside out and upside down worked....cough.
Thanks for the inputs.
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