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Discussion Starter #1
Ok, I have an 85 supra with the 5M-GE in it. when I bought the car it started and ran BUT it had serious blow-by and smoked worse than a Jimmy Hendrix concert. So I had the motor rebuilt and had it bored out to .40 over. New piston heads, new plugs, new crank, new wires, new vac hoses, cold air intake, new distributor, new coil....

Now, I have fuel pressure, oil pressure and starter is strong. the timing is perfect AND the distributor is timed. however I am getting very weak spark when I first turn the key and then no spark at all.

Since I have a new coil I am thinking it is the Ignition Control Module... TRUST ME distributor is timed and gapped perfectly.

also when the car sits for a few minutes i will turn the key to the ON position NOT START and the motor will try to turn over!!! I took the coil cable off the distributor and placed it near the intake manifold and recreated the even and sure enough when in the ON possition it threw a strong blue arch to the intake manifold for about 2 seconds and then dissapeared (this all being accompanied by a very ominous sounding buzzing)...

Question is, is my "ICM" bad or does it have a bad ground pulse... and where does this ground pulse come from in the first place!

Pleace help... thank you in advance :)
 

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sounds like the ignitor is shot, or the coil is wired backwards or something. ive never wired one backwards so not even sure it would do this if it was. also, the starter should not try to turn while the key is in the on position. you have some wiring issues somewhere.
 

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Discussion Starter #3 (Edited)
sounds like the ignitor is shot, or the coil is wired backwards or something. ive never wired one backwards so not even sure it would do this if it was. also, the starter should not try to turn while the key is in the on position. you have some wiring issues somewhere.
Its not that the starter is trying to turn. The igniter and coil are giving off a powerful arch of electricity for about 2 seconds causing the distributor to fire on whatever piston its on and then the motor tries to turn over from there. But this is only after I have sprayed a little ether in the intake so I know its just burning that.

Bottom line is I'm not getting enough spark AND I'm not getting a negative ground pulse to the injectors telling them when I'm at TDC.
 

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if the injectors arnt firing, the ecu isnt getting a signal from the distributor. so it may be the ignitor.
 

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Discussion Starter #7
I'm buying an MSD 6al ignition module with rev limiter, MSD tach adapter for the objectors and tach and a blaster 2 coil with resistorr and brackets.... So hopefully that solves the problem :)
 

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Ignition Control Module

If U do narrow it down to the ICM or igniter and need OEM ones, PM me with the part #'s...

The ones I have are mainly for '84's but should be the same.

Hope things work out...and I'd be curious as to what the final problem is in case I ever run into the same thing with one of my '85's...:frown:

Cheers,

I'm buying an MSD 6al ignition module with rev limiter, MSD tach adapter for the objectors and tach and a blaster 2 coil with resistorr and brackets.... So hopefully that solves the problem :)
 

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where in Texas?? last time i looked the local yard had 85 with igniter, also check autozone as they had one for my 83 at decent price. pm me if you want me to check out junkyard part/price
 

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Discussion Starter #11
Well time for the update. I got my parts in a few days ago and have been getting everything hooked up. I fabed up a custom brace for the ignition module that way it could sit where the stock igniter did. I also mounted the coil between the radiator and battery and my tach adapter on my firewall next to the "engine tag".

This is how I have the ignition module wired:
thick red to battery +
thick black to battery -
thin red to switched 12v source (Original coil +)
thin black to coil -
thin orange to coil +
and the thin white to nothing due to what the "instructions" say.

I have the tach adapter wired:
Red to switched 12v source (Original coil +)
Black to original coil -
and green/green to the ignition modules magnetic pickup port.

Yet I am not getting any spark when trying to turn the motor over.... What gives???
 

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Find a good ignitor and replace...always good to have a spare coil and ignitor

But could be EFI relay...

Check the TSRM follow diagnosis no spark...

 

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DBrown what yr Supra??
 
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