In step #55 of the instructions it says:

"If you have installed the VR input circuit jumpers in step #52, the stim is not currently designed to put out the sort of signal (AC) the VR circuit expects. However, by adjusting the pots at R52 and R56 ....... it should be working"

Here are my specs:
PCB: Version 3.0
Processor: MS II
RPM Input Circuit: Variable Reluctor (VR)

When I hook up the stimulator, all of the other inputs work (TPS, O2, IAT, CLT), but in MegaTune the RPM dial is a red color, and doesn't respond at all, even if I fiddle with R52 and R56.

 

you can't just "fiddle" with r52 and r56... you need to turn them both all the way counterclockwise.

another quick question? Why are you using the MS2? that doesn't have any support for rotary ignition at all... You'll really only be able to do fuel only, or EDIS, or something like that.

 

Nice catch. It's for my friend's car. We're building his first and then mine. Mine is a MS I. Fiddle was his term. lol. I just copied his post from the MS forum in order to save time. We've tried going counterclockwise on R52 & R56 and still nothing. There must be something wrong with the circuit.

 

you have to go fully counterclockwise..

you also have to make sure you jumper everything right:

Jumper vrin to tachselect, and tsel to vrout or vroutinv... for the ms1 you want vroutinv... for the ms2 it doesn't matter.

 

i need an answer for this too. the manual says it wont work unless u mess with R52 and R56. i mess around with them and get nothing. they need to be full counter-clockwise when it is connected to the car it says. im trying to use the stimulator to make rpm in megatune. can this be accomplished when jumpered to use a VR sensor?

 

One good thing to do is bench test everything, even if it is installed in the car. Get your hands on a spare cas and plug it in and spin it by hand to make the sparks trigger. The stim is a usefull tool but setting up the dual vr's for me was a bit confusing because the first time I installed it i had two wires backwards triggering one of my trailing coils insted of the leading pack. Spinning the cas by hand lets you watch the plugs and see what's going on.

Just my opinion.

 

good idea. i will do that when i get home but im in a hotel room right now and id like to test it with the stim. can this be done or not? the instructions act like it can but i dont see anything.

 

If you're using ms1, you need to use "stim for wheel" to test on the stim unless you have the jimstim.

On ms2, you need the jimstim, the regular stim won't work.

Ken

 

still not working. how do i diagnose this circuit? what kind of output voltage should be where? is there any extensive info on this?

 

am i missing something?




i had to use a different transistor in Q23 but it had the same specs. ive put ms extra on it and have set all the settings like shown in the FAQ. i cannot get rpm to show up with the stim even when i have "stim for wheel" on.

where do i go next?

 

[removed]

 

hi what is the diff between vrout and vroutinv thanks

 

vroutinv is inverted of vrout. i would think alot of people have had to diagnose the vr circuit or got rpm into megatune with the stim.... ANYBODY?

 

I've never had a problem getting RPM from the stim to the MS personally, even using the VR circuit.

If you use stim-for-wheel, and set it to "2," then hook up to the stim, you should get a signal...

Are you sure the stim isn't what's broken?

Do you have both of the pots turned fully counterclockwise? That has always worked for me, answering yes or no to that question... you just said you fiddled with them.

Ken

 

yah i have them all the way left till they click. i did fiddle with them too cause thats what the manual says. i dunno if the stim or the circuit is broke then, is their no guides to diagnosing this? "X voltage on this part of the circuit" etc? i dont know how the vr circuit works, i THINK its suppose to take and AC wave and turn it into a square wave so MS can read it. but i dont know how the stim works etc

 

The stim outputs a +12v square wave... the VR circuit should have no trouble reading this... you can verify that it's doing *something* if you have a multi-tester...

Just check voltage on the jumper from VRIN to TACHSELECT jumper... it should not be 12v or 0v, somewhere in between... even better would be to scope that same place, and make sure you're getting a good +12v square wave.

If your multitester has a duty cycle setting, it should change when turning the stim rpm pots.

Ken

 

so do i use vroutinv for my 3 vb921's off the led's with the correct ohmed resistors maybe muay could answer this

 

if you're using an ms1 and your VR sensor is wired correctly, then you should use vroutinv to tsel...

It has nothing to do with the vb921's... You only need vb921's if you're directly driving the coils though... if you use the stock 2nd gen or 3rd gen systems, you wont' need these.

Ken

 

i am going to run cut tooth CAS with 3 vb921's wired

through LED 14 15 16 replacing the 4.7k resistor with a 200ohm for the leading

and two 330ohm - 400ohm for the trailing plugs

this way i wont have to run in inverted spark keeping the trailing split operational

 

i am going to mount the VB921's in a seperate remote box and PCB with a microtech style plug to a modifies MS1 V3.0 Box for my coil drivers

 

here is a diagram of what i am thinking of doing or the other otion is 3 VB's and a multi coil for leading [

 

i removed c31 per matt @ diyautotune, and it worked right away. i tried putting a .01 uf cap in place and it still doesnt work. still works with c31 out though. heh.

quit thread jacking rx3_pp

 

i wanna know the same answer with my setup but sweet would you like me to start my own i will mate

 

C31 is a noise-filtering cap, it should work with that there (I've not had any trouble getting any of my own setups working with that in)... Maybe a weak CAS signal?

Ken

 

it wasnt hooked up to a cas. it was just the stim. i put in a smaller cap and it works fine now. go figure.