need help with install wiring

[bmcewen]

MSII with v3 main board,relay board, chevy small block 383, msd6al,blasterII coil, small cap 8pin distributor(stock from 89 camaro) in 78 camaro. I want to control the timing with the ms

as far as i can tell i need the white wire from msd to pin 36 (through relay board pin 11)
pin B is going to Fidle on the relay board for spare port use
Pin R goes to 'tach' on the 20-position terminal block (which in turn connects to DB37 #24).
Pin C ,Pin + will be unused since the coil will be powered via the msd6al
Pins P & N go to the VR sensor.

So where/what do i do with pin E ?
is it no longer used?

[bmcewen]

or does pin E have to go to Pin 36 to control the timing in which case where do i get the signal from for the msd?

[Matt Cramer]

You can go about this in two ways. One, you could wire the MegaSquirt to control the HEI, like this:



Then run the MSD white wire to the HEI C pin instead of wiring the HEI to the coil. This would use standard HEI mods.

Or two, you can run the white wire to S5/pin 11 on the relay board and not use pins B or E on the HEI module since the MS is controlling the MSD box directly. This would need a BIP373 or switching transistor in the Q16 slot of the MS.

Actually, there's a third option, take the HEI out entirely, but I'm not sure there's any point if you already have the HEI.

[bmcewen]

Alright its all together now and i chose to wire the C pin to the msd( everything else is wired per above diagram) but i have no spark at plugs and there is no tach signal at tach or in megatune

[bmcewen]

Also I checked over my board assembly Wichita seems good and everything works when hooked to the stim

[bmcewen]

MS2 V3 newest code...383 SBC, gm 8-pin, msd6al. I have no spark at plugs, tach sits at 0, megatune reads 0 for everthing related to rpm. Any suggestions?

[bmcewen]

Is there any way to measure the tach signal coming out of an 8-pin hei while cranking? I can spin the dizzy out of vehicle with a drill and measure the VR pickup but I need a way to measure the signal after the module. I'm not getting a tach signal and want to trace the circuit....I had the module tested so I know its good. Everything checks out ok on the stim, and I've rechecked my wiring several times. I really at a loss...

[Matt Cramer]

It's tough to measure the tach signal without an oscilloscope. Could you post your MSQ file? I'd like to check it for RPM killing settings. Also, can you get RPM on a Stim?

[bmcewen]

I tried using winscope today (got no signal), tried running the tach wire directly to tach(still nothing but not sure if that should work) ive had the module tested at autozone (they claimed it was good) everything seemed to be working well on stim until i ran the hei mod(msnse) per the manual, haven't tried since then, not sure if you still need the msq, im have problems posting it

[bmcewen]

Also my voltage while cranking drops from 12.4ish to around 9(+/-.5v it kinda bounces around a little) this is measured where the 12v switched is soldered to the relay board im not sure if that would cause a problem but im looking into how to fix it...battery in trunk, high compression, high torque starter

[Matt Cramer]

Pin C ,Pin + will be unused since the coil will be powered via the msd6al

Oops, I missed that one. Your problem is that the module isn't getting any power.

[bmcewen]

Ok so i thought that vr created its own voltage and since i remove my old ignition module i never had power going to the dizzy....anyways i hooked up the switched 12 volt to the + pin and now i get a faint signal in winscope which i can measure in dcv on the mm but its only .25ish volts while cranking, the switched 12v drops to 8.8v and it seemed to have a high spike(or drop?) initially in winscope. But still no rpm readings in MT and still no spark....at least we made some progress

[bmcewen]

I think I may try the transistor hei mod to increase the signal and/or drop a cap in the power line, would either or both of these possibly help? I can't seem to find much info on the capacitor thing ( where to put it and what size cap to use, etc....) anyone know how to do that?

[bmcewen]

So with out changing anything i decided to try data logging just to see what the log looked like while cranking. The first time i cranked it i noticed the rpm needle jumped , so i hit the key again and it fired and ran for a few seconds before i shut it off( garage door wasn't open). Going to look into this more tomorrow....no clue why this happened

[bmcewen]

Ok so the car wouldn't fire this morning (not sure why it was starting last night) so I installed the transistor mod from the hei inputs page I am getting a signal in winscope but still no rpm in MT, bat voltage still drops to around 8.8v while cranking (does it thave to be at least 9?)

[bmcewen]

Spent the day measuring voltages and traces and wiring and can't get any leads as to why it wont start, or to why it started twice then decided not to anymore, rechecked with the stim and the MS still seems to be working so it's either in my settings or in the dizzy, if its not raining tomorrow i might swap the dizzy from my truck in to see if that changes anything

[bmcewen]

Today i replaced the distributor with the one from my truck which i know was good. When i tried to start the car it would just lock up like the starter didn't have any power and the MS would reset. I took the distributor out and the engine would crank just fine,I then reinstalled the distributor and now the engine will crank but i have no rpm in MT. Is it possible that i am some how blowing these modules? If so what could being causeing this? I'm going to reinstall one of these distributors back in my truck to see if it works anymore after it stops raining.

[Matt Cramer]

If you have the output on when it should be off, you can set a HEI module to charge the coil full time and fry the module.

[bmcewen]

I'm assuming you mean spark output...

Ignition Input Capture Rising Edge
Cranking trigger Trigger Rise
Coil Charging Standard Coil Charge
Spark Output Going High (Inverted)

this is what the manual says it should be....mine may have been on going low(as per the msd page)....should i need to have anything different from what the manual says? I have the transistor hei mod installed (should i remove that?) or does the msd require anything different? the hei input page is kind of confusing to me when it comes to these settings...im getting ready to grab some modules from the salvage yard so it would be nice to know what these settings should be at before i try again.

[Matt Cramer]

Setting it to "going low / normal" if you have JS10 wired to the HEI module can fry the module.