hi guys... been a while. finally had a chance to get at working on this ms. i decided to buy a new kit and start fresh. to recap my dilema, i had a v3 missing tooth working perfect but wouldnt get a rpm below 400 or so. on the cas or the stim. however when i ordered it through diy i got the msii with the daughter card. and the only cas i have right now is a missing tooth. so i went ahead and built this thing with that in mind. and i reused the ms1 chip from my secondhand ms from before. i did all the faq mods i think.

so...
i decided to leave out the hall/optical sensor parts and just built the vr part.. is this okay?

i left out the iac parts too because i dont want to use it. the flyback and all that stuff for pwm...

i plugged into my laptop and started up and it looks like everything is working and sensing, but i dont have a tach signal from the stim. all my setting transfered with the chip to the new board. and my laptop settings are the same. but no rpm. its a whole new vr circuit on the board, so... is it possible there is something wrong with my processor? havent had a chance to hook up to the car harness yet. i think i ruled that out last time tho.

 

i was skeptical while building whether or not i should install r57, d1, d2... the directions where a little unclear for my situation being that im not putting everthing on the board.

 

For getting a tach signal from the stim, you have to use the stim-for-wheel setting (on ms1) or use something like the jimstim (ms2).

Also make sure that you have the two potentiometers that are part of the VR in circuit turned fully counterclockwise, Make sure that VRIN is connected to TACHSELECT, and VROUTINV is connected to TSEL (MS1), or VROUT is connected to TSEL (ms2).

Ken

 

already done all of the above for ms1

 

remember i had a post that said i had bought a second hand missing tooth ms1 v3. so i cleaned it up and got everything working except the rpms when using the harness. and it was because my car wouldnt crank 400 rpms. itwont see rpm any lower for some reason. and i went round and round trying to figure it out. and said screw it... i got a brand spanking new one from diy. built it. and omitted the stuff i said above. and once again, everything works but the rpms. i just havent had a chance to try it on the harness with the cas. but i get nothing in stim either. i wanna try it on the car in stim mode and not. with igniters unplugged of course. but yeah, the ms1 chip i reused and the code and settings. code 29v

 

no suggestions huh?

 

have you tried readjusting the sensor gap on the CAS?

 

ive tried it the full range. i tried cleaning the teeth and the pick-up. i switched the pick-up. tried a non missing tooth cas, and also re wired the cas with twisted leads, long and short. cleaned grounds. wheel for stim and not wheel for stim, with the cas and the stimulator. and like i said before... i pulled the cas out of the engine and spun it fast with a power drill and i got an rpm reading but just not below 400. i went from 0 all the way up to like 26,000 rpms( i think the range of the drill) so it would be like 13,000 rpms onthe cas. and megatune read everything from 400 to 13,xxx rpms. and when i slow it back down to 400 it will then go below and still read. but to start the car, i have to start with a fresh reset. so no luck on the -400 rpms. originally thought there was a bad part in the vr circuit, so i bought a new ms and had new everything. less the chip.

 

As long as you have the pots fully counter clockwise, all the wiring right, etc... I see no reason why this shouldn't be working for you.

Can you post your latest msq?

Ken

 

this should work.

 

settings look fine.

This one must be wiring or hardware.

Ken

 

well ken i only see so many options....... replace both my cas because i have tried two. replace the u1 chip, download diff firmware... or replace my laptop. these are the only thngs i havent done yet. but like i said before, this is also with the stim. so i dont think it has anything to do with my car. i guess i will retry the firmware download with a different release version. if i get nothing from that i will replace u1. and if i still get nothing im moving my desktop into the garage.

 

I think it is more likely that the problem is with your tach input circuit. Could you take a picture of that?

Ken

 

hope these help

 

If I were you, I'd probably go over the solder joints in that circuit with a hot iron again, just reflow the solder on those joints.

I see a few that look like they could be cold joints, and a few where it's hard to tell if there are solder bridges or not.

 

hey-- somebody, ive been trying to trace my missing tach signal. i used a multimeter to test the voltage at the tachselect and vrin jumper with the stim on. i get between like .11V and 2.75V at this junction but when i test on the tsel and vroutinv i get a steady 3.67V no matter the pot position. is this normal? im trying to trackdown when on the board the rpm disapears. thanks

 

smackhead, i am having what appears to be the exact same issue you are right now. hopefully we can help each other work through this. my electrical engineering buddy is mostly the one working on this issue, not myself. I'll ask him to post in this thread and tell you what he has found so far. let me know if you get any further with this.
good luck, we'll be in touch.

 

ok.

i also have tried 3 different firmware version, 29q,w, and y. with the same ms1 processor chip ive had. i do have a ms2 card and i have started researching the ms2extra stuff. i found the good guide someone did on here for controlling spark correctly. but i didnt know if i should install it. not knowing the tach signal problem.

but since i tested the tachselect vrin joint, i see a reasonable display of voltage there, that would indicate that the cas should be able to get it there, based on my previous diagnostics on the harness and cas. but when i wanted to test further up on the vr circuit, i didnt really know where to check. if i can find that the signal goes far enough to let me install the ms2 card etc... i can install it and get this whole ms1 version, chip, and headache behind me. maybe.

 

No signal means that either you have a bad component on the board (maybe you fried the op-amp while soldering?), or bad wiring, or a bad CAS.

AT this point, I'm leaning towards the op-amp being bad.

My suggestion is to call up DIY and have them send you another op-amp, and get a socket while you're at it. Solder in the socket and put the op-amp in that. That way there's no chance of overheating it while soldering. The only other components that could have been overheated in that circuit are the two transistors down near the bottom of the board.

As long as those three components have not been overheated, that circuit should be working.

On the board that wouldn't work below 400 rpms, I'd have said that you just need to adjust the sensor gap closer, and make sure both pots are fully counterclockwise.

Finally, once you get a signal on the stim, if you still don't get one in the car, I'd say check over your grounds and power to the MS, noise on either of those will keep the VR circuit from working properly.

I'm willing to bet that switching to ms2 would not solve anything, as I don't think the problem is the chip or the code. (In fact, I'm sure the problem isn't the chip or the code, as I and several others have had those running no problem.)

Ken

 

2 quick questions that will greatly help me narrow down this problem:

1) how important is it that the CAS wires are insulated, or in a "twisted pair" set up? right now the 2 CAS wires are just attached to the board in no particular way.

2) what rpm does the 13b typically crank at...we measured about 80 rpm by listening to 6 exhasut pulses over about 2.2 seconds, and dividing that by the 3 revolutions of the E-shaft it takes to make 6 exhasut pulses.

3 rotations/2.2 seconds => 81 rotations/minute
is this a normal cranking speed?

 

normal should be like 150-300 rpms cranking. i doubt you will see 300 tho. i think i was cranking at like 180 with a weak battery.

its prolly easier to count the rpms from looking at the cas spin arount. i think every tooth that passes should be 30* of crank rotation. do the math to figure it out. keep in mind this is no piston motor, so your formula for figuring this kinda stuff out is not generic.

the cas needs to be shielded or atleast twisted with high quality cable.

ken i did see one other guy had no signal for a while and finally got it when his sensor was closed up to the wheel teeth. but i think his hit the sensor. ive had mine close enough that the sensor magnet pulls on the teeth as the pass by. like i could feel the magnet grab each individual tooth, and it would have resistance when i tried to turn it again. but i can try to move it closer. i tested the harness when i did this on my first board, and got a voltage, albeit low, at the db37. this was when i got signal above 400rpms. i think i will try that board first and set the sensor as close as possible with out destroying it. if nothing. i will call diy and buy new vr parts... the op-amp and socket. for good measure i might just order two new transistors too. i also bought a new harness from diy when i ordered the v3 board. so i will use that for the cas wires to just go ahead and eliminate that question. thanks. ill be back.

 

1) The CAS wires should be twisted pair, with a metal shield around all the wires. The metal shield should be grounded in one place.

2) I usually crank at around 280-300 rpms... 81 rpm doesn't sound right.

Ken

 

oh yeah ken, i also did go back and reheat all my solider to make sure they werent cold applications. i hit everything. but my reason for suspecting the ms1 chip was when i put it in backwards and tried to start the ms up, and it obviously didnt work. didnt know if i could have hurt it. and like ive said i have tested rpm signal in the curcuit up to tachselect and a few other unknown places. i know its getting there, but whether its strong enough or what i dont know

 

Ahh, I must've missed that you put it in backwards.

I had one that one once from a customer that had built his own MS, but it wasn't working... he sent it to me, and turned out the CPU was in backwards when I got the unit. I flipped it back around, but several things were broken.

If you put that CPU in backwards at any point, it might not be a bad idea to spend the $15 or whatever it is now, and get a new CPU while you're at it.

Ken

 

yeah, i think i mentioned that before like in my first thread about this more than a month ago. but its cool ken. i had suspected this could be a problem but no one said so.

anyway... like i said when i ordered my new v3.0 board, i got the ms2 kit by accident. i already have this. should i just go ahead and set it up for ms2. from what i have read so far on it, it seems the better way to go. i figured id just get the 1.0 firmware. it looks like it has all kinds of goodies. but if you really think i should, i will just get another ms1 cpu. lemme know what you think ken. thanks