HEI7 mode - manual correction

[jsmcortina]

There was an error in the manual. Dwell control MUST be used with HEI7/8.
Do NOT use fixed dwell like the manual stated.

James

[TheRipper]

That´s very important! I fried my HEI8 with the wrong settings


Now I´m running dwell control with 2.5ms dwell and it´s fine!

[turbo355]

Been wondering about this i have a 2.2 board in a Honda del sol right now that has a HEI 7 pin in it and it was over heating i added a ballast to the coil and now it dosent , but i have the dwell control set to fixed like the DIY site says.

I guess i will try dwell control on it and see how it does.

I thought the HEI module controlled the dwell ?

[jsmcortina]

I thought the HEI module controlled the dwell ?

It does not control the dwell during running. Dwell control is required.

James

[turbo355]

Yep changed it to Dwell control and it works just fine now.

Might need to change the software manual so more people dont get confused on this.

[Wes Gardner]

ok since the GM DIS coils are basically the same setup would they also need dwell control or simply set the dwell to the fixed 50% duty?
Thanks

[nukkinfuttz]

yeah, what about DIS with that is based off of HEI7? affected or not? what are the symptoms of having a problem?

[rkmason]

FYI, I have been working to configure a system using the Northstar V8 DIS ICM together with a GM MEFI controller to operate an LT1 version SBC. I have determined that the Northstar V8 DIS (and I assume the 4cyl & 6cyl DIS units) control their coil dwell independent of the EST input signal duty cycle. The DIS ICM just uses the EST input signal falling edge to fire the coils.

What I can't find info about is the EST input signal duty cycle requirement for the DIS ICM to operate. I hope the DIS ICM can tolerate a wide range of EST input signal duty cycles.

[Peter Florance]

while we're on this, I noticed on the 5.7L truck I was playing with, setting timing to 10 degrees with bypass disconnected located the distributor where I needed large trigger angle #'s (~ 20 degrees) to get correct timing, which seems problematic.

I need to revisit it, but I'm thinking setting dist to 0 degrees in bypass (Megamanual mentions this as a possibility) may work better

Comments?

029y4 MS1 code; GM 7pin module.