Ok ... I parked my 86 for a week,and went to go start it... Gee.. Its cranking an awful long time... So i check for fuel.. Yep, got fuel, Check for spark... No spark.... So i change the coil/igniter to my backup unit... Still nothing... So i check for voltage at the coil... 12v... Check for good ground at the coil (I wasnt sure if this was a chassis ground unit or not, but the other wire appears to be dead and does absolutely nothing, and has no ground.... ) I REALLY need to figure this out.... Any suggestions?

 

Apparently, I would assume i'm not getting a pulse to the igniter.... Is there a way to check the crank angle sensor? are they generally pretty reliable? or maybe something else i should try?

 

The bullet connector at the coil assy is NOT a ground and should not ever be put to ground.

The ground for the coil/ignitor is the housing of the coil assy that bolts to the chassis at four points. No extra wire is needed for a ground. Even one bolt holding the assy down would do the job.

If you have 12v at the black/yellow wire on the coil assy, that should also mean the ECU is getting fed by the mAIN Relay, so you should get spark also.

CAS are dead reliable. Very reliable.

I have a dead sure way of seeing if the coil assy is good or not, but you have to know how to install a cas, so I won't mention it now. Well maybe. PUll the cas out of the engine but leave the electrical plug installed. Now pull one of the lead coil wires out of the coil and lay it so it just rests on the bore of the coil assy. Turn your key to ON. Now spin the cas's bottom gear rapidly. I bet the wire at the coil sparked. So, tell us how it worked out.

 

Well, I know for a fact its NOT the coil assy, I have 3 of them... and i KNOW one is definitely good, b/c it starts my friends RX7 , as does the one in my car right now... The coil has power, but is not firing... I've tried 3 of them...

 

I'll put it this way. One known thing about spark, is that if the reference voltage in the ECU isn't there you will never ever get spark. To easily determine if you have the ref voltage, go to the brown/white wire on the boost sensor and see if you have approx 4-5 vdc.

Ref voltage goes away when someone grounds any of the brown/white wires. If that is done the ref voltage will never return til the ECU is sent off to be repaired.

Another thing that will keep spark from not happening is if the ground terminal for the ECU is not bolted down on top of the rear rotor housing. No ground. No spark ever.

Another thing. A very slowly rotating engine due to a low battery or broken starter, will drag the batt voltage so far down you won't get much of a spark to look at.

I suggest you borrow a cas from the other car and install just the electrical plug on it. Then turn the key to On. Spin the cas gear with the lead coil wire just hanging on the edge of its bore. Leave the other lead coil wire inserted. When the cas is rapidly turned spark, LARGE spark will occur. IF not then its time to get the meter out and do what I described above.

No meter? Then save the bucks and have someone fix it for you.