booch

iTrader: (2)

i am currently building my standalone megasquirt-I v3 for my 90 turbo (no ac or cruise). i have completed up to step #50. i am trying to verify if i am building the right components.

if i am reading things correct on the DIY site....i build the hall/optic/points for the tach signal, but omit the option portion of the build that "...that say to only install them if you are triggering from the negative side of the coil; you aren't - so don't."

if i build this circuit, do i skip the VR circuit portion of the build? or do i just have this all backwards?

Joe Perez

iTrader: (8)

Yes, that's basically correct. You'll build the hall/opto input circuit, and then later modify it with a pullup to accept the CKP signal from the CAS. You'll also add a simple second circuit to accept the CMP (2'nd trigger) signal as well.

You can build it if you want, it'll just sit there not doing anything until at some point in the future you decide to upgrade to a crank trigger wheel. Or you can skip it if you're lazy and are sure you'll never want a VR trigger.

ScottFW

iTrader: (4)

The easy way to figure this out is to read Brain's stickied SUPER Important Megasquirt Thread on How to make and install your own Diy MS. He has a component map in there, and if you don't see the part on that map, you don't need to install it.

wayne_curr

iTrader: (8)

I used that component map for my build as well. Every step in the megamanual that gives you a "choice", look at the choices...if one involves installing a piece that is not on brain's component map then you shouldn't go that direction.

Also, DIY's writeup is very useful as well.

booch

iTrader: (2)

thanks for all your replies! i will make a printout of that map as a guide.

the build goes on.

booch

iTrader: (2)

so i have gotten to the next step of testing (input construction) with my jimstim. all the pots on the jimstim seem to work along with megatune except rpm's. i have yet to do the mod for the tach input due to me missing that i would need the extra resistors in the mk-pullup mod kit.

please tell me this is why i don't have any response in megatune.

Joe Perez

iTrader: (8)

This is why you don't have any response in MegaTune.

booch

iTrader: (2)

so i completed all the mods for the tach signal as per brain's and DIY's diagrams......and no go for rpms from megatune.

hmmmmmmm

booch

iTrader: (2)

DIY helped me out here. 2 emails, 2 missing jumpers on my jimstim, and i am back in business.