Intro: I have a '7730 computer, from Howell Engine Management connected to a four barrel TBI unit.

According to them there is a little circuit board within the harness that "filters" the ignition pulses and feeds it to the computer.

They want to sell me another circuit filter so it will work with my MSD for $50!

I was hoping some one here can help me avoid the $50 admission fee to use the MSD.

Basically, the MSD connects to the five wire HEI circuit. Both the Howell, and the MSD get the feed from module. When I connect the MSD to the module along with the 730 computer, I no longer get the fuel injector pulse. If I disconnect the MSD from this connection, it works as expected.

I have also tried connecting the TBI computer to the TACH output on the MSD with no success.

Thanks in advance.

 

Do you got it connected to the battery correct? I've had that same problem with my stock ecu, but it was because the feed to the battery wasnt getting any power. Also make sure its grounded thats another reason mine was working right cause I just had it grounded to any old thing. Make sure all your connections are good and sound that ur getting power to the unit, then if that fails your going to have to go with the prom chip the company wants to sell u to get it working with the msd ignition.

Good Luck

 

Thanks for the reply.

UGGhhh.... Howell seems so proprietary, I might just convert it back to a Stock TBI 7747...


Looking at the non-computer controlled HEI cap from the top

signal from Module, ground, positive.



I followed MSD directions for connecting it to the 5-wire HEI.
Basically, the MSD connects to the signal side, with positive. My computer connects to the same wire as the MSD.

I do get spark from the MSD, I checked it with a timing light. Just no pulse reference to the computer...

 

The MSD advertise lower primary resistances than the stock coil. Since the coil and compter are run in parallel, the lower resistance of the MSD coil takes power from the computer compared to stock coil. I bet the computer still gets signal but not enough for it to recognize. Unfortuneatly I dont know of any way to correct it.


Charlo

 

Thanks for the info!

Hmmm I wonder if I use a couple of resistors, and maybe a diode.

Damn, I am not an EE.

ANyone else?