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Post by danm54 on Jul 22, 2013 9:34:07 GMT
What vr sensors are people using for efi? I've got a 36-1 trigger wheel and the stock gsxr vr sensor but I keep intermittently losing signal when I turn the engine over, sometimes its fine but most the time it drops out after a second or so.
Its wired up correctly, the gap is set to 0.1mm (much further away it wont pick up at all) and the engine has been running but it wont now. I've also tried another 2 sensors 1 which came off a working bike but I get the same issue.
Do these sensors work with a 36-1 wheel or do I need a different one?
Cheers
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Post by nitro on Jul 22, 2013 10:39:21 GMT
On the Ignijet I always use original pick ups with 24-1 trigger. I tried GSXR1100W, CBR1100XX, Z1000 pick ups – works perfect.
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Post by mattturbocar on Jul 22, 2013 10:53:43 GMT
gsxr1100w sensor can work fine with 36-1 wheel, I've had tis working fine on 2 engines (different VR sensors). On my megasquirt install I have an LM1815 conditioning circuit and I don't have any problems. The inductance of the VR sensor is quite high, so I had to add some more resistance (as compared to others using the same circuit).
Do you think that you might be picking up noise from the starter/earthing whilst cranking? I run a shielded wire back to the ECU.
Do you have a means of collecting a log of the signal from the VR, I put an oscilloscope on and it was very informative.
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Teresa O.
Velociraptor
Posts: 37 
Bikes: Trickframed 1127, Turbo 14 and many more
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Post by Teresa O. on Jul 22, 2013 10:55:23 GMT
I recently used a 24-1 also on Microsquirt... although I changed the triggerwheel 3 times coz the signals on the oszylloscope where not as MS wants them to be ... have a check there..
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Post by katana on Jul 22, 2013 19:29:29 GMT
I sort of cheated with mine! Used a stock GSXR trigger wheel with the wide tooth ground down to same as other three to give a 4 tooth trigger using stock pick-up but also added a cam trigger. This gives a nice wide tooth space to avoid noise and false / dropped teeth and perfect 90 deg space before firing tooth. Using a Motec M8 ecu
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Post by arttu on Jul 22, 2013 19:39:19 GMT
Even though several people are succesfully using a 36-1 wheel on GSX-R engines with stock VR sensors I think it's a bit gamble. Tooth size gets so small that the sensor may have difficulties to detect teeth reliably.
But before changing the wheel or the sensors there are few things to try out. You can try to adjust signal level by adding a resistor in series between the sensor and signal input or on parallel with the sensor. For series resistor I would try values between 5-50 kilo-ohms and for parallel resistor between 100-1000 ohms. Then trigger signal is often very sensitive for external interference. Typically output side of the ignition is the most significant source of the interference. You can try resistor plugs if you don't have them already. Adding a 5-20uF capacitor between 12V supply of the coils and ground helps also. And naturally it's a good idea to keep the VR sensor wires and coil wires far away from each other.
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Post by danm54 on Jul 22, 2013 20:43:38 GMT
The pick up wires are shielded as they came pre wired with the ecu.
I have found the problem now though, a faulty ground on the ecu seems to have caused it. Every time the wheel was touching the engine it didn't work, take it out and spin it with a drill it was fine!
I did bodge a 12-1 wheel out of a 36-1 wheel and it reads that much better than the 36-1 so I'm going with altering my 36-1 into a 12-1.
Its running now but the rpm is erratic so im hoping the 12-1 will smooth it out a bit.
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Post by mattturbocar on Jul 23, 2013 11:01:39 GMT
Just a word of warning. I previously modified a 36-1 into a 12-1. The reason I did this was because I was on MS1, and thought that it couldn't keep up. Not sure whether my logic was correct, but the 12-1 did work with MS1.
When I moved onto Ms2 (and I had replaced the engine with a dodgy ex-sidecar version) the problem that I got was that I had a lot of RPM variation when cranking which resulted in it struggling to get a decent fix on the long gap. I built a new 36-1 and all was good.
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Post by danm54 on Jul 23, 2013 11:24:12 GMT
The Microsquirt V3 seems to like the 12-1 ok, I've had a proper rough one in a drill waving about and its picked it up fine with a steady rpm. Even loosely bolted to the crank it picks up ok.
The bike runs on the 36-1 but I have to set the pick up within 0.1mm to get a reading and then tick over is all over the place.
I'll try the 12-1 and see how that goes, I cant see it being an issue but if it is I'll have to make a 24-1 from scratch.
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Post by mattturbocar on Jul 23, 2013 11:37:29 GMT
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Post by danm54 on Jul 23, 2013 21:35:05 GMT
Well I'm back to the same problem...
The 12-1 wheel works fine off a drill but attached to the engine it reads for a second then drops off exactly the same as the 36-1 wheel done.
Which is really weird as it it was running on the 36-1 last night!
I'll check the ecu loom connections tomorrow. If they're good I think I'm going to have to add a pull up circuit before the vr sensor.
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