analog EFI

[Chris Morriss]

In message <0ECX7NG8T00FZ7 at kauri.lincoln.ac.nz>, Simon Quested
<questeds at whio.lincoln.ac.nz> writes
>Hi All
>
>I have a '73 Ford Capri with a 2L 4 cyl engine I also have an analog 
>EFI system that I am about to put in. It uses a map sensor and a 
>pickup from the -ve of the coil to control only the fuel. It has 6 
>pots that set the on time for the injectors over the rev range.  
>
>I want to put a MSD ignition module in but I think that this will cause the efi 
>ecm to freak out?
>
>Am I right in thinking this?
>
>Thanks
>
>Simon
>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  Simon Quested (E-mail questeds at lincoln.ac.nz)
>  Computer Technician, Silicon Graphics & Windows NT Support
>  Centre for Computing and Biometrics
>  LINCOLN UNIVERSITY OF NEW ZEALAND
>  Phone (64)(03) 3252811 Ext. 8087
>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>http://www.lincoln.ac.nz/ccb/techs/simon/default.htm
>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>If voting could really change things, it would be illegal. 
>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
It may not.  I'm not sure which of the MSD units do the "multiple spark
discharge" thing to the coil.  I don't think they all do.  If it is a
multiple discharge type then it probably will screw up the trigger
signal to the efi unit.  It may depend on the time constant of the input
filter in the unit.
Is it not possible to trigger the EFI unit from the MSD ignition
trigger?  I don't know if this is a Hall effect trigger or the variable
reluctance type, but it will give you one pulse per cylinder.  It's a
pity that the MSD module doesn't put out a trigger-output pulse for the
synchronisation of external EFI units.  (It might do that of course,
perhaps someone else might know)

bye,
-- 
Chris Morriss