ms1 v2.2 - rpm connection, edis trigger wheels

[bryan01]

in my last post i asked the question about where to connect my RPM signal from my MS on my rb, and was directed to trigger wheels. i'm looking for more info on this. can i just buy one of the following

 

http://cgi.ebay.com/ebaymotors/EDIS-36-1-Trigger-Wheel-VR-Sensor-Megasquirt-Megajolt_W0QQitemZ110127328818QQihZ001QQcategoryZ33689QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

and attach it to my harmonic balancer in the front, and wire it's sensor to the RPM of the megasquirt? it says it's a EDIS wheel. does the EDIS system need to read the signal from this and then send a signal to the megasquirt or can i just use this wheel/sensor directly with the megasquirt? i want to keep the stock ignition system for now, thus trying to get fuel only from my megasquirt. it's hooked up and working well, just need a usable rpm signal.

 

thanks for the help.

[Matt Cramer]

The trouble with an EDIS trigger is that it uses a VR sensor, and to use it with a V2.2 board you will need to build a conditioner for that input. In your case, since you are running fuel only, I would recommend splitting the sensor wire on the six hole ring between Megasquirt and the stock ECU. Do not run any pull-up resistors or anything like that, just wire it to both. This should get you an RPM signal both computers can use.

[bryan01]

I would recommend splitting the sensor wire on the six hole ring between Megasquirt and the stock ECU.

 

can you be more specific? i'm sorry about asking for verification but i just want to be sure of what you are saying. what does the "six hole ring" mean? are you talking about the ring (like the trigger wheel) on my stock engine, and the sensor that's on it? do you mean that i should split the wire right at the sensor?

 

previously i tapped into the crank angle sensor wire to the stock ecu (at a point right before the ecu) with the rpm wire from the MS and i got fuel. so you're saying (just so i understand) this is a good RPM signal that the MS can use and decipher as RPM? it's not just seen as a random voltage by the MS that happens to be equilivant to an RPM voltage during cranking that enables it to squirt fuel, right? if thats that is the case, that the MS can read this as RPM, then i just need to figure out how to split it between both computers. when i hooked it up like this previously the signal to the stock ecu didnt get thru (not enough power to send the signal down both lines?)

 

when you say to "split the line" do you mean tap into the line at that point?

 

as you can tell i'm not the greatest electrically, i only got a C+ in circuits.

 

also, i've tried tapping into both the (2) 120 deg crank angle sensor wires to the ecu and gotten the same results. there are (2) more 1 deg wires. could taping into either of these give a different result?

 

thanks for the help, and for bearing with my questions.

[bryan01]

V1.01, V2.2 PCBs VR sense

The older v1.01 and v2.2 boards do not include the VR input circuits so you will have to build a circuit on some proto board or buy a PCB off the forum.

LM1815 based VR sensor conditioner for V2.2 or v1.01 - optional is a 390R resistor across the VR input.

 

 

i got the above from the megasquirtnspark-extra pages. http://megasquirt.sourceforge.net/extra/setup-wheel.html

 

i'm assuming that's the board i'd have to built and put inline between the VR sensor and my v2.2 board if i wanted to get a RPM signal that way.

 

so what are my options?

 

1.build the board i need to run a VR sensor, buy the VR sensor and trigger wheel, attach it to my harmonic balancer and run the RPM signal wire to the VR sensor thru the new board

 

2.modify one of my sensors with one of those autronic wheels (see pic below, also from the msextra pages) so that the megasquirt can read the RPM signal from that sensor. but would the sensor still be able to send a signal back to the stock computer for spark?

 

Another COP example, this time an autronic wheel retrofitted into a CAS (spins at cam speed). As this is a 4cyl there are four outer holes. The single hole is the 2nd trigger "reset" pulse.

 

3. ? connect the rpm wire to the crank angle sensor and somehow split the signal between the 2 computers?

[Matt Cramer]

can you be more specific? i'm sorry about asking for verification but i just want to be sure of what you are saying. what does the "six hole ring" mean? are you talking about the ring (like the trigger wheel) on my stock engine, and the sensor that's on it? do you mean that i should split the wire right at the sensor?

 

previously i tapped into the crank angle sensor wire to the stock ecu (at a point right before the ecu) with the rpm wire from the MS and i got fuel. so you're saying (just so i understand) this is a good RPM signal that the MS can use and decipher as RPM? it's not just seen as a random voltage by the MS that happens to be equilivant to an RPM voltage during cranking that enables it to squirt fuel, right? if thats that is the case, that the MS can read this as RPM, then i just need to figure out how to split it between both computers. when i hooked it up like this previously the signal to the stock ecu didnt get thru (not enough power to send the signal down both lines?)

 

when you say to "split the line" do you mean tap into the line at that point?

 

as you can tell i'm not the greatest electrically, i only got a C+ in circuits.

 

also, i've tried tapping into both the (2) 120 deg crank angle sensor wires to the ecu and gotten the same results. there are (2) more 1 deg wires. could taping into either of these give a different result?

 

thanks for the help, and for bearing with my questions.

 

The six hole ring is the 120 degree crank angle sensor, and this is the RPM signal Megasquirt is looking for. It is not designed to work with the 1 degree wires.

 

You can split the wire as it comes out of the sensor and run one to the stock ECU and one to Megasquirt. If the stock ECU loses the signal, try putting a 500 ohm to 1K resistor in line with the Megasquirt.

 

The Autronic disk will work with Megasquirt, but it won't work with the stock computer.

[bryan01]

http://www.gweeds.net/carpage2/RevCounterCircuit.pdf

 

here's a link for others, how to get a tach signal (12v square wave) from a coil on plug setup.

[BRAAP]

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What CAS is that exactly, i.e. what vehicle and years did that come from?

 

Thank you,

Paul

[bryan01]

not sure what car that's from (it is a 4cyl b/c of the hole count/spacing). that picture came from the megasquirt extra page setup link i posted above. i was just posting it as an example of a CAS with a wheel on it that the megasquirt could read from.

 

they modified the cas, adding that wheel which you can buy from autronic.

 

as it turns out i shouldn't need anything that complicated from my application, but we'll see.

[bryan01]

thanks everyone for your help, i installed the circuit above that i found on that other board the other day to get an rpm tach signal to the megasquirt, and it fired up and idled perfectly the first go. it's amazing what happens when you have fuel and spark at the same time ... ... thanks again, i'll be posting up my megasquirt settings on my rb once i get it tuned