Trigger Wheels

[DGGT6]

Hi Guys,
I bought one of TimW "pressed metal" trigger wheels quite a while ago and have been installing the Megasquirt stuff with many more problems than I imagined.

How is the wheel supposed to be presented to the VR sensor?
I bent all the teeth/tabs over 90 degrees so I would have a wider target area for the sensor to read. In its flat form the wheel only presents about 2mm width to the sensor and I thought that a bit of wobble may take the wheel outside the range of the sensor.

Is the VR sensor reliant on a certain quantity/thickness/solidness of metal passing by to generate the voltage? Currently with my bent teeth, I only have a 2mm deep piece of metal passing by, but other "machined" wheels have a solid "block" 40mm deep (into the centre of the wheel) by 6mm thick.

Does anyone know or think this may cause troubles?

Still on trigger wheels, is there a particular ratio of "tooth width to gap" that should be followed? Currently I have 9mm wide teeth and a 7mm gap. I have heard of people using 1:3 ratio, being a 8mm tooth with a 16mm gap.

Thanks for any help,
Regards,
Doug

[Deleted User]

Doug, my wheel was cut from 3 mm steel and worked fine until my conversion to zetec,  that wheel should be fine what problems are you having?

[James]

Just make sure the VR sensor is close enough — not more than a couple of mm away.

[DGGT6]

Thanks guys, you can view some of my sob stories over on the MS1 forum....
http://www.msextra.com/forums/viewtopic.php?f=4&t=51451&sid=0938783632f6ebd2241ce00826da8228

Basically my MS1 V3 came second hand with no accurate info. I started with the EDIS mods and couldn't get a good tach signal, then the MS would shut down over 1200 RPM then come back on under 1200 RPM. I changed the polarity and even changed the sensor with no success
It just seemed every way I turned, something didn't work as it should. I couldn't even get fan control to work the relay. The middle LED would go on and off at the set temperatures but not the relay. Curiously the stim IDL LED would go off when the middle LED came on.
I did have the O2, water temp, Inlet temp gauges working.
So I have started looking "outside" the MS unit and found out about using resistor type spark plugs. I haven't had a chance to try my new plugs yet.
Now I have started wondering if the thin trigger wheel maybe playing a part in not generating enough "current" for a good signal and whether I should have bent the teeth over or not.
A local self confessed geek from another forum has offered to look over my MS and once he gives it the thumbs up, I will have eliminated my MS mistakes and the actual MS unit, so any problems remaining will be from the car side of things. (I hope!)
Thanks for eliminating my wheel as a problem source,

Regards,
Doug

[Deleted User]

Doug I know several people using your type of wheel, some on Megajolt and all seem to work fine. If in doubt borrow a solid wheel. I have a spare but its in Manchester and I am 300 miles away and not due to visit for a few months.

My wheel was ebay about £15 and was solid water cut from 3mm steel.

My sensor was about 1mm away from the wheel and never missed a beat. It would work further away from the wheel also.

Good luck and keep us informed of your findings

Rob

[chamchella]

I am thinking of fitting cruise control to (Stag) and understand that I will need to fit a trigger to the prop shaft to get road speed feedback.

Is there a well trodden path to follow in doing this? I am having enough issues with simple stuff and do not want to overcomplicate it.

[Deleted User]

7270 wrote:

I am thinking of fitting cruise control to (Stag) and understand that I will need to fit a trigger to the prop shaft to get road speed feedback.

Is there a well trodden path to follow in doing this? I am having enough issues with simple stuff and do not want to overcomplicate it.

I don't think you will need a trigger wheel, it may take the reading off the bolts?

Some others may correct me?

[rlubikey]

bobyspit wrote:

I don't think you will need a trigger wheel, it may take the reading off the bolts?

Yes, this certainly works with a Hall-type sensor. Should also work with the more common inductive sensor.

(I did an electronic speedo for the Atlas in this way, with a tacho for the readout - in front of me so I don't have to peer over to the centre consul  :) )