EMI Problems?

[Andrew Wakeling]

Hi All,

I'm not sure if this topic's been discussed previously before, but I'm
going to start it off nevertheless. OK, EMI (Electromagnetic
Interference) is a popular topic discussed throughout the electronic
world and it is known to cause many strange problems with electrical
devices. Devices had to pass certain EMI tests and they had standards...
CE marks might ring a bell. Anyhow, what does this all have to do with
the Delco you ask? 
I have a strange feeling that many problems on high load/high rpm may be
caused by EMI produced by the spark lead or ignition modules. A friend
of mine had such a problem and moved his coil pack around the car, with
suprising results. The car basically went from running badly, to not
running at all. 
What I also discovered was that if spark leads were changed, and the
standard ones were replaced, the ECM was more prone to these problems. I
am also experiencing similiar problems with my data logging device and
think that its due to this EMI interference... however, I am unsure how
Diacom gets around it.

Dave Zug wrote:

> my website (under the buick GN section) has a link to pictures of the graphs
> during this glitch - high load, high RPM, it just goes berzerk - and the car
> goes into 31 degrees retard!  It does cause I felt the power loss big time.

This problem I think is associated with EMI. Diacom may keep on logging,
and maybe its interface, being composed of simple transistor networks
and the like, are less prone to EMI. Since Diacom is also being used in
the parallel port, a serial routine isn't being used, making
interference less significant maybe? If Diacom was designed so that it
would actually follow the whole serial transmission instead of just
points along the byte, maybe results would be 100% accurate.

Does anybody have any views on this? Has anybody solved any problems of
the such with insulation or shielding? Anybody know how Delco filters
signals without shielding their cables? Is Elvis still alive? If you
have any answers, please reply to the group!

Andrew Wakeling.