MS2 with hei 7 pin questions???

[CantZme]

So, I've had my Z for 5 years now and tried installing megasquirt 2 times now with failed results both times. I'm not really knowledgable as far as electronics go but have gotten myself into an unfortunate situation which I cannot solve and now i have no car to drive. I've started to wire the car up again and am now using the MS2 3.57 ecu. I will be using the stock 83 l28et motor and distributor with the stock CAS running to a gm hei 7 pin module. I am now extremely confused as to what goes where as reading the megamanual has only confused me further. I will be using the relay board, but it seems like I need an extra relay from which I will connect the B terminal on the hei module to receive the TPS5V signal from the relay board?? can someone clarify the purpose of this...am I running this for the sole purpose of a 5v source for the hei module? As far as the 1/4 watt 1k resistors I need to add, I have no idea where they go in my application nor their purpose...any help is appreciated?

[NewZed]

Did you see lowrider's thread? - http://forums.hybridz.org/index.php/topic/97253-hei-spark-control/page__pid__913356#entry913356

 

The 8-pin GM HEI module is essentially the same as the 7-pin module except it has a separate ground wire.

 

The relay is to give 5 volts to the B pin only when the engine is running. It allows the car to start with the original static timing, then applies the Megasquirt timing advance when the engine is running.

 

That's all I know.

[Matt Cramer]

I will be using the stock 83 l28et motor and distributor with the stock CAS running to a gm hei 7 pin module.

 

That is not a combination I'd recommend - I am not sure 7 or 8 pin HEI modules are at all compatible with the optical trigger. It would make more sense to use an ignition module from an Optispark equipped LT1 if you have an urge to add GM parts. (The Optispark was a Nissan ignition grafted onto a smallblock Chevy.)

[CantZme]

could you please elaborate, im really bad with this stuff. why do you not recommend the 7pin hei module. I know that the 4pin hei module is used in mobythevans's install which was what i was originally following but the megamanual suggested the use other module as the 7 pin controls spark as well and is more reliable. can you clear up the resistor confusion as well, what is the purpose of the resistor and where does it go?

[mario_82_ZXT]

The megamanual is more of a universal/basic theory kind of manual.

 

You should really be following Moby's or DIYautotune's install guides.

 

Also, if you're running MS2 on a newer board, have you built the ignition driver circuit? If so, you don't even need an HEI module.

[mobythevan]

Yes, with MS2 you should use the coil driver on the megasquirt board if it fits your application. Lots of people use it and there will be much more support than using the 7/8 pin HEI.

[CantZme]

I thought the stock vb ignition driver is not reliable enough to run a coil directly. Don't we need to swap in the bip 373? At that, I dont feel comfortable soldering the bip373 in, but if I have to, I will. Why can I not use the 7 pin module? Matt Cramer, how come you are saying the 7pin hei is not compatible with the CAS? it was used in the install that NewZed linked in the post before yours

[CantZme]

thanks moby, I hoped you would chime in...the resistor portion of your install has me confused as well, can you clairfy the purpose of the resistor and where it goes?

[CantZme]

ordered the bip373 mod kit

[dexter72]

You can also use the Bosch style ignitor that is mentioned in the manual, I use that and it works perfectly.

[mobythevan]

When you connect the trigger wire from the optical CAS to your relay board/megasquirt it requires that a resistor also be connected to make the CAS actually trigger megasquirt. Connect the CAS wire to your megasquirt like the manual says, then add the resistor from that wire to 12 volts. Verify that megatune shows rpm during cranking.

[CantZme]

thanks a lot moby and everyone who responded. The wiring is finished and I am waiting for the bip373 mod kit.