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Okay summary. Im at the end of a 240Z turbo swap.

I have had the car running already, but for some reason now it wont start, because there is no spark coming from the coil.

I have 2 extra sets of coils and modulators (that small elec thing on the coil bracket) and This is not where the problem is stemming.

There IS power to the coil and modulator.

Yet still no spark. It is narrowed down this far and I dont know where else to look.

once again, I have tried different coils and modulators and still no spark.

the black wire to the modulator is getting full voltage, and the yellow is getting about 7-8 volts while cranking. From what I understand this is how it should be.

So then what else is left. could the crank sensor have gone bad in the distributor? is that possible, and would it have these symptoms if it did.

thanks alot to whoever can help me on this. NB
 

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Sounds like the distributer to me. 82 and 83 have the cranck angle sensor inside, the 81 has it on the cranck itself. I'd try that next. Good luck,
Jim
 

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Old Hat, but FSM...

I know this will sound old, but do the checks for no spark in the troubleshooting section of the Factory Service Manual. What you need to do is carnk the engine while monitoring the signal from the CAS at the ECU. If the ECU is recieving the signal in a square-wave form (I believe this shows up as a 'pulsing needle' on the VOM) then it's doing it's thing. The CAS gives a signal to the ECU, and afterthat, the ECU processes it, and sends a gating signal to the power transistor (modulator) at the coil to determaine when it shall fire.
If you have no input, you've found your problem.
If you DO have the pulse signal, then you have to dig deeper.
I'd get that FSM out, and go step-by-step and TRUST YOUR INSTRUMENTS. It's really simple if you follow the steps, and believe what the tests tell you.
Good Luck!
 

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Just a picky note....

but if you have full voltage normally and 7-8 volts during cranking, then the inputs there are backwards. The lower volts should be during RUN and higher volts during CRANK. If you are running a later ignition system though, there is no ballast used and the system is designed to operate on full 12v all the time, both start and run.
 

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Re: Just a picky note....

I agree with Tony D. I had a similar glitch once. I had corrosion from a bad splice in the wire that leads from the ecu to the ignitor. I found it using the methods Tony decribes.
 

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Re: Just a note....this is a turbo swap INTO a 24

Since you're putting a turbo INTO a 240, or that's what I gather, here's a couple really nitnoid points. You may have already addressed these and if so sorry for the waste of a post, but just in case.

Did you swap out the wiring harness on the car for the one that will power the turbo? Just the engine harness or did you do the harness inside on the dash as well? If yes to both then you've changed all the electrical connections for the turbo, however, if you just connected into the wiring harness for the 240 dash, then you have to remember that in those cars the tachometer was a REQUIRED part of the ignitor circuit. If the tachometer was disconnected, the car will not start, this is of course with the original point distributor but also applies with the 79 dizzy conversion if you still have the original 240 tach.

And on the off chance that you've also changed the tach, did you correct the wiring for it? The 240 used a loop as well as being part of the circuit (4 prong connector) but there was also another one that didn't require the loop, it was grounded to the instrument frame if I recall right. (3 prong connector)

Just my 2¢ worth.
 
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