8 replies to this topic

[Mix_67]

So a few years back I picked up a Microsquirt module from a buddy. He never got around to building it. I am hoping to get it set up for a TBI Build in my conquest. The module documentation is a bit patchy so I hope you all can fill in some blanks.

I am a mechanical engineer with a background in field service including lots of schematics and wiring troubleshooting. I have 90% of my pin out tables laid out, but I am stumped when it comes to ignition.

Currently the car has a msd6al with tach adaptor using the stock knock box. From what I gather my best bet is to take out the 6al, add a 7pin gm hei module and lock the dizzy. Is that the right approach?

I auto-x the car hard and want to ensure I have a reliable rev limiter so I am nervous to pull the 6al. How much power would I be leaving on the table to keep the 6al go fuel only and keep the stock dizzy arrangement? How do I eliminate the knock box?

[MotoCam360]

Talk to Scott87Star about all MS stuff.....he's a genius!

Since you autocross, did you baffle your oil pan?  Diehardmitsu just released some nice weld in baffle pieces for the stock panel.....hit 'em up if you need some

[Mix_67]

MotoCam360, on 27 January 2021 - 01:24 AM, said:

Since you autocross, did you baffle your oil pan?  Diehardmitsu just released some nice weld in baffle pieces for the stock panel.....hit 'em up if you need some

I never had baffled my pan or run into any issues. I always just checked the oil before the event and made sure it was topped off just above the full mark on the dipstick.

That being said I do have a spare oil pan soaking in some degreaser (for like 3 years now..... ) that I had intended to add an fittings for turbo drains and some baffling to. I will have to check out his offering. I always wanted to do one of the Teflon edged crank scrappers from back in the day, but never goat to ordering one when I did my rebuild.

[scott87star]

Modifying a stock system is very easy, the OEM distributor pickup is a VR signal and microsquirt accepts a VR signal directly, a no-brainer.  And the rev limiter in the MS system is far superior to the MSD box, you can spark cut, fuel cut and spark retard with all the settings at your fingertips in the software.  You do need to lock out the advances in the distributor and you do need to lock the vaccum advance in the correct position and done!

BUT, your system has been modified and you have to figure out a couple of things first.  The factory knock box controls the factory coil, the MSD also controls the coil but at 540V compared to 12V so one of them isn't controlling the coil.  I'd say its the knock box, probably been bypassed if it is still sitting in the engine bay.  Personally I would keep the MSD, they do offer a hotter spark than the factory setup and microsquirt can run it very easily, just use WLED out from the ECU to points input on the MSD.  That fixes coil control, next you have to figure out rpm in, you mention a tach adapter, check where that is wired in.  It should be on the tach output from the MSD going to the factory tach and back to the factory ECU for its rpm input.  If so, good, then you can bypass the wiring that goes from the distributor pickup to the magnetic input to the MSD, route it to VR + and - on the microsquirt and you'll have rpm in.  If not a lot of guys used a caravan pickup in the distributor paired with an MSD tach adapter to provide rpm input to the early MS1 stuff that couldn't accept the VR input, I doubt that it is set up that way in this case because I assume its now running on the factory ECU.

[Mix_67]

Scott,

My ignition was modified using the faq on this site in 2008 by me when I got the car from AndyW. Unfortunately the schematic seems to no longer show up in the faq due to broken links. I used the 8910 tach adaptor and retained the stock knock box. The factory dash tach also still works.The car is in storage or I would go sketch it out.

I have a spare dizzy that I can lock, however the fip instructions that I find referenced on here all have broken links. Do you happen to have a good link to instructions on a lockout?

I will review the wire diagrams I have for the Microsquirt module, msd, and tach adaptor and see if I can figure out how to arrange them.

[scott87star]

Are you planning to mount the module in the factory ECU case?

[Mix_67]

I was not planning to use the stock ECU case. Originally I considered it as an option, but I want to replace the engine harness completely anyway so I just got a hobby box to modify as a housing. Planning to use a 22pin weather pack bulkhead as my main connector with a db9 serial port connection for comms and a short pigtail with a 4 or 6 pin weatherpack as power connector.  Mounting a "ignition" relay for my switched 12VDC+ power, a small fuse block, and a small terminal board in there as well. The only wires I will be reusing from the stock harness will be a keyswitch signal to drive the relay, and the positive to drive the factory fuel pump relay.

[Mix_67]

I found this diagram elsewhere on the site: http://www.starquest...howtopic=128162

NotStock88, on 04 March 2012 - 12:36 PM, said:

i also found this.. hope these help;

From what I gather my MSD8910 tach adaptor would go across the distributor signal connection. One side of the distributor signal goes to 12Vdc+. The yellow wire above would go to OPTOIN+ (Pin19) on the MicroSquirt, leave OPTOin- disconnected.  The Red wire above (=white points trigger on the MSD 6al)  would go to the IGN1 on the MicroSquirt on pin 48. The MSD Coil+ and MSD Coil - would also go to the coil. Wire the MSD 6al power to print (12V+, 12V-, and keyswitch). The coil + would not be hooked to the 12V+ because it now feeds from the MSD.

Edited by Mix_67, 28 January 2021 - 07:57 AM.

[scott87star]

That is the setup for the caravan pickup module, you don’t need that and I don’t recommend doing it that way since the micro module can take the factory VR pickup output directly, as I’ve already described.