MS1 build issue - rpm tests
 

So yeah... build has been going great. A local miata friend let me borrow his megastim for the build and its been quite usefull.

I've made it through power/serial/cpu socket tests and was just testing the datalogging. I got it reading and all the stim controls make changes... except RPM.

I configured mine for the hall/optical sensor. Jumpered for it and all... nothing. I've rechecked/reheated all joints on the stim and the MS that could have anything to do with it... nothing. I've even installed the VR components, even though they are bypassed with the Hall/optical jumpers... Nothing.

Anyone have any thoughts? All components look good, solid joints etc... I'm stuck.

well i think its good that you checked it out with megastim ... other than that idk

I have same rpm problem
 

I am on the same step and am having the same problem.

I have found the following on the MSEFI form:

"Have you looked here:
http://www.megamanual.com/ms2/V3trouble.htm
especially 1, 2 and 10?

That document has a number of things you should look at (on a V3 main board) if you don't get a tach signal on the stim."

I have been to busy to try the info on that link but it looks like it steps you through testing the rpm circit.

Eddie

Yah, i've done part of it. I'm going to get some acetone/alcohol and do some cleaning also...

If I find my reason... I'll post it up here to see if it helps you.

please do the same ;)

I had the same problem, then I switched the RPM switch on the Stim and my tach signal came back. I don't know why I lost it, but switching the switch to the other position fixed it. Did you try this?

Keep us posted.

Contact cleaner just fixed a little gremliin on my board. I would HIGHLY recomend it now and when you are finished.

Can you elaborate? Switching it to what "other" position? I'm game for trying anything :p

And cleaner is a definite now :)

RPM switch
 

I moved the switch to both positions with no luck before.

The switch is on the stim right next to the RPM pot if you have v2.1 stim.

Does anyone know what these switches are used for?

Eddie

Well, I've cleaned the stim and the MS... no changes. I'll continue trying to debug.

v2 stim btw.

I got my rpm reading last night and was able to start up with megasquirt controlling fuel which was a great feeling. what I did was first, clean my board with rubbing alcohol and a toothbrush, then heating up each individual solder joint, taking extra special care at the 5 or six spots where there are three very close points. If there was too much solder, i removed some, if there wasnt enough, I added a bit.

You haven't done any of the board mods yet have you?

Make sure XG-1 is jumped the XG-2
TSEL is Jumpered to OPTOUT
TACHSELECT to OPTIN

I guess I'll try reheating them again.

I've done both rpm signal systems, and jumpered those 3 for the Hall/optical selection. Nothing.

What spots did you feel were the close points? I'm curious. The closest ones I saw where the Qs for the VR system... which isn't even used with the jumpers we use.

Sigh... I'll keep at it.

For the megasquirt to work on the miata the opto basicly just needs to be installed and thats pretty much
it. Let me look at the schematic and see if anything else is needed.

Yeah, basicly XG1 to XG2 basicly grounds one side of the diode in the opto.

D1, D2, and R12 just to pass the signal from TachSelect to the opto. R12 is pretty much
just for protection. It can be jumpered out too.

No luck yet... been over solder joints, cleaned board of excess flux and no help from the troubleshooting page....

ARGH! Anyone know the info of the one electronics guy that can help with MS repairs? I'm about at wits end.

Can you connect to MegaTune to make some configuration changes?

I can connect and read data from the stim. I just don't get RPM. So i've stopped around step 62. I even installed the VR stuff.. just to be sure :p.... even though the jumper settings for Hall... bypass it.

Well dont get too down, i think i may have fixed my rpm spiking issue ... but then it was replaced by intermittent restarts or possibly just loosing the rpm signal. Finally it just stopped starting altogether and i dont know wtf happened.

Heh... I'd just be happy to get any rpm signal at all. Then I can proceed to build the rest of the MS.

Stim seems fine, joints all re-checked. MS stuff looks fine also, also all re-heated...

:Sob:

Do you have the wheel decoder setting in megatune that the miata would use? Once that is set rpm no longer registers with the mega stim. If you have it plugged into the car though you should get rpm. This may not help you if you are trying just the default settings you have after you flash a new msnse version.