Computer Controlled Hei Thread

In the not too distant past I seem to remember a thread about computer (ECM) controlled HEI distributors for Dauntless V6's. I have since tried to find this thread with absolutely no luck. Is my Alzheimers kicking in? Too much Knob Creek? Haven't seen the ball since the kickoff? Anyone remember this thread, or can point me in the right direction? I've tried any conceivable key word search I can think of. thx,

 

Hmm. When you say "computer control" that means spark advance under the control of the EFI's ECM. I don't recall that there was any way to control spark with an odd-fire engine. The problem is how to switch back and forth between the 90 degree and 150 degree firing angle on alternate cylinders. Even fire, yes easy, but odd fire? Maybe you could do it with the latest Megasquirt using a trigger wheel and coil on plug, but it would be a project if possible.

All of the commercially available EFI products for odd fire are fuel only, AFAIK.

The Meagsquirt page discusses the various HEI modules and how they connect for spark control - General Motors 7-pin HEI Ignition Control - GM never offered EFI with the odd fire engien, so there is no native support for such a config.

Knob Creek is pretty good ... I like their rye best.

 

The article I was referring to was, if I am not mistaken, regarding an EFI ECM controlling a HEI with a 7 pin module. Now I am really questioning my sanity. IIRC it was referring to a GM ECM that had been reprogrammed? I don't remember the details as it was at the tail end of a 40 hour day (insomnia) I suppose it could have been pertaining to MegaSquirt, but I sure thought it was GM ECM. AFAIK, MS has had odd fire spark control since V2.xxxx thru internal programming and hardware.
I will search for MS HEI, Focker.
I have had several emails from Matt Howell in the last 10 days saying Howell kits support odd fire V6's, and their components are available separately. I'll have to pull up the emails to verify spark control. Affordable was asked the same questions about their kits, they replied emphatically it was "NOT possible without very expensive additional parts"
Thanks to all, shack

 

Mmm, you sure about odd fire spark control? I know that the Megasquirt ECM will time-average the tach signal to get an RPM reading, but I understood that was for a fuel-only setup. Can you point to the man page where this is described? You understand the issue with the firing angle?

AFAIK the Howell kits are all fuel-only, and previously would not work with odd fire. The GM ECM has no support for odd fire AFAIK, and making it work fuel-only with odd fire would require some additional circuitry to modify the uneven tach signal.

 

Although it says AMC, look at the pull down. Oddfire Buick is listed:

AMC 6 Cylinder DUI Distributors - Performance Distributors

Never owned one of these distributors, but I hear enough good things about these that I want to change that soon.

 

But like Tim said, those are NOT a computer controlled spark advance/retard distributor. Another AFAIK those do not exist for the odd fire. At least for anything available off-the-shelf.

 

I am not looking to buy an aftermarket HEI, I have followed MegaSquirt since its' first version, and I am aware of the odd fire time averaging feature, not in the market for a complete system. I am not complaining or scolding anyone. I am looking for an thread that was posted here in the last six months or so, regarding making an HEI with spark control provided by the ECM. IIRC the thread was regarding an ECM controlled HEI with a 7 pin module, ESC, knock sensor. I could very well be wrapped around the axle here, I am not perfect!

I reviewed my emails with Matt Howell, he indicates his GM based EFI will do both spark and fuel control on odd fire V6's, Howell reflashes the prom in GM to accomplish this, and no crank trigger is required.

Thx to all. shack

Focker, I did a brief MS search, no bueno, so far.

 

I could be overlooking something, but I don't see how they could spark control an odd fire without keeping track of where the engine is in the firing order. I believe this is done for coil-on-plug systems using a pickup where the distributor would normally sit. This gives the computer a pulse for every two rotations of the crankshaft, providing an index to the firing order. Such an index is more than you need with odd-fire - there, without changing anything else, you need the firing order phase so you can calculate the adjusted interval to next firing - unless you go full coil-on-plug. One possibility might be to monitor the interval between distributor triggers and infer the phase from that. This would require additional processing from the ECM, which may or may not be within the capability of the CPU. It's a lot more involved than reflashing the ePROM with new look-up tables, but may be possible with existing hardware.

 

Maybe one of these threads - site:earlyCJ5.com "7 pin" HEI module - Bing

 

Tim/Focker, I think we are getting closer, thank you for your help. I think my word search "computer controlled HEI" is probably too limited.

I don't know how Howell makes a GM based ECM work, I am certainly not a programmer or computer engineer. He wrote to me and said it works without a crank pick up and using an ESC module. He also said he was not familiar with a 7 pin HEI, which I thought was necessary ECM to control spark????? I have not seen their system work myself, so I can't say with certainty that it does.

Something many are not aware that any discussion regarding odd fire v6's ignitions needs to be confined to ODD FIRE V6'S. Talking about any other engine is comparing apples to oranges. The advice on V6's on this site has been pretty accurate, thank you all.