I have a 92 Saturn which has been running rough at cold startup and ping under
a fairly low load. It has a DIS ignition system, and I get no flashing error
codes when I short out the correct contacts. I checked the RPM's with my Fluke
meter: plugs 1 and 2 don't seem to have a spark according to the RPM meter
function (I don't get any RPM's at all); and on plugs 3 and 4 I get an RPM
reading. I should think I should get a reading on all 4 wires, right?? It has
two coils: coil one services 1 and 4, while coil 2 service 2 and 3.
I opened the Chilton's manual and they suggest testing the resistance between
the two posts of each coil: it should be around 30,000 ohms or so. The first
coil showed the 30,000 ohms, while the second one showed several Mega-ohms.
That suggest the Mega-ohms coil is bad. Problem with this is that I was getting
a spark on one of the wires leading from that coil.
Chilton's says a Mega-ohm coil should be replaced, but I went on as Chilton's
also suggests switching the interchangeable coils. I did this, and the high Ohm
coil was still high Ohm, and the low Ohm coil was still low. This again
suggests that the high Ohm coil needs to be replaced. Problem is though, the
same two wires still are dead and the same two wires show an RPM reading.
This suggests that the problem is in the ignition control unit; two circuits
are bad and therefore the icu should be replaced. Problem is, I don't get any
error lights, and off of the "bad" coil I am still receiving a spark.
Please give this lost soul some words of advice. Don't know how to work on
these new fangled systems!!!
Clayton
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