Join Date: Sep 1999
Location: Austin, Texas
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Re: Anyone install an MSD on their Howell TBI??
You haven't cut into your Howell harness have you?
I did. There is a tach filter in the harness near the ECM plugs that is between the white coil(-) and the green B5 ECM terminal. It is a small circuit board .5x1.5"s. It has an IC, resisitors and capacitors.
If you notice in the manual you sent:
5. AFTERMARKET IGNITION SYSTEMS: If you are running an aftermarket ignition system (MSD, Mallory, Jacobs, etc.), you might not have a coil signal that will trigger our <font color="red">built-in tach filter</font color>. If your engine will not start, and you have one of these systems, contact Howell Engine Developments at Ph 810-765-5100 for assistance.
2. ............Connect the labeled white wire to the ignition coil negative terminal to pick up a tach Signal. NOTE: Multiple spark discharge ignitions require a <font color="red">special Tach filter</font color> to function correctly..................
It is in there it is just so small that you wouldn't know it. If I would have know about it when I started this project I probably would have gone another way. Now that my harness is built and installed, I can't live without one. I tried something else today using a GM ignition module parallel to my duraspark module, and it didn't work.
Oh well..... This should clarify the tach filter issue for anyone that is interested, or thinking about creating a fuel only TBI system.