85 Coupe GT ignition coil specs?

Chris Hall bad_comrade at megsinet.net
Sun Aug 1 02:30:17 EDT 2004


Can anyone please tell me with certainty what the ACTUAL primary and 
secondary resistance specs for the coil on a 1985 Coupe GT CIS-E 5cyl 
engine are?  According to this quote from a 2001 post, the Bentley 
specs are wrong(?):


Everything appeared in spec.  I was getting 3200 ohms of resistance 
from terminal 4 (center pin, to dist) to terminal 1, and .8 ohms 
between terminal 1 and 15 (pos and neg coil terminals).  This matched 
up with the ranges that I was supposed to be getting.  Upon closer 
inspection though, I noticed that the coil shown in the Bentley was 
different than the one that I have in the car.  I had been using the 
diagnostics for the 4cyl cis-e, as most of the tests are the same as 
for my 4kq, and bentley does not have any info for 5cyl cis-e cars.  
Looking at the specs for the cis-eIII cars, I noticed that it uses the 
same coil, and the specified range between terminals 1 and 4 is 4000-
5000 ohms.  So, my coil had too low of resistance, and was shorting 
out the ignition module.  Yup, I'm an idiot. Dropped the new coil in, 
and new replacement module, and car seems to be running quite well.


My -Haynes- manual lists primary spec as being 0.52 to 0.76 and 
secondary spec as being 2400 to 3500, which seem to be what the guy in 
the quote above's Bentley listed, which are apparently incorrect (and 
my 1985's coil resistances both fall within those limits as did the 
coil from my 83 that I tested for the hell of it).  I'm guessing that 
might mean the Haynes specs were also only for the 4cyl 1982 engine, 
especially since the chapter tells you to check for newer updated 
specs for 1983-1987 cars in chapter 13, yet has no "new" coil specs in 
chapter 13... nice.

I ask because I had the whole "Tach falling to 0 engine stall" 
problem, fixed it by sticking my old `83's ICM in it... but now I'm 
getting the occasional quick engine cutout after the engine warms up 
(and the ICM, COIL, warm up) and occasionally that causes a stall, and 
I'm wondering if indeed MY coil is below spec and is eating up the 
replacement ICM I have in the car now...  

Another "hint" may be the fact that I had installed a brand new Lucas 
ICM in the car, it ran great for 5 minutes (which it could do with the 
bad ICM), and then the tach signal went crazy causing the tach needle 
to dance all over while idle was steady... then 3 minutes later, the 
engine idle went all over and eventually the engine gave out... I 
attributed this to a bad "new" module... but now I'm wondering if my 
coil may have killed the new ICM, and my 83 ICM that's in there now is 
just a little "tougher" fighting off the coil but is starting to lose 
the battle...

Chris Hall
bad_comrade at megsinet.net
"making girls cry since 1974"

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