no spark! 87 4kq

[Edward R. Wendell IV]

Disclamer: no BTDT on a 4q

So with the ignition on, engine not turning you measure 12v and with 
the engine cranking you measure nothing as in absolutely nothing (zero) 
or just a "garbage" reading other than 12v?

The reason I ask is, in general, digital multimeters, especially cheap 
ones, are useless on any sort of switched/intermittent voltage. The 
internal brain just isn't fast enough to keep up. When the engine is 
cranking the coil is being alternately grounded/ungrounded and with the 
low resistance of the coil and a slow meter it may be normal to measure 
something close to ground on either terminal of the coil. I believe 
that the position sender in the distributor is a hall effect type so 
you may be able to see the switching of the coil if the engine is 
turned over by hand (disconnect the hight tension lead and ground it so 
the engine doesn't start with the wrench in the pulley) but not knowing 
the behavior of the ecu/ignitor combo I can't say that for certain.

I don't know about 4k coils, but I've had a lot of old cars with a lot 
of miles on them and never had a bad coil. I tend to think that the 
replacement coil biz (at least for the older type round can coils) is 
driven purely by mistaken identity as to which component of an ignition 
system is at fault for a no spark condition.

In short, don't go installing a new coil without further guidance and 
testing unless you've got money to burn.

Roy Wendell
Morgantown, WV USA
86, 87 5kcstq
87 MR2 times 2
Three turbos, two quattros, too much fun