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Nissan NSF6A2 Low Compression

doing the electrical testing of the ignition coil. Manual says to measure between Black/Yellow and "core". reading should be .38 Ohms.
wahat is the "core"?? Ground?
thanks
 
"Core" is the metal core of the coil, which is at ground. There are 2 readings to take; Primary side and secondary side. Primary is bk/yl wire to ground; Secondary is plug wire to ground. You could also check for a short between the primary and secondary (wire to plug wire), should be very high or infinite ohms, but that's a very rare failure mode.
 
OK - rec'd a new Pulsar coil, Ignition Coil and CDU. Using a 'good' ohm meter, I measured new pulsar coil at about 200 ohms. seems to be IAW spec in the book. Ignition Primary circuit measures about 40 ohms -very close to spec. But the secondary circuit - Plug wire to ground - measures about 10,800 ohms and the book says 3000-4400 Ohms. Given that it is new, I will believe it is OK. Then measured about half of the circuits listed in the manual for the CDU. That is where I couldnt get anything to match up close to spec. I stopped for the night and will try again tomorrow.
The meter I am using is an old Tach/Dwell/Ohm meter. I installed a new battery and aside from a scale that is hard to read, it appears to be working fine. I just dont understand why the readings for the new CDU are not closer to the table in the book.
thanks
 
My Factory manual for the 6A2 refers to the CD as having mark CU2568. On the Tohatsu parts system, that comes up as 3R1060601M C.D. IGNITION UNIT (CU2568) NEW STYLE. Perhaps your is an older or supereceded part? Also keep in mind that where coils are involved, tolerances are very wide; 40% off is not unusual.

More to the point, do you have spark now? and if so, does it run OK?
 
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Paul: I received the new style CDU marked with CU2568. I replaced the pulsar, ignition coil and CDU but still NO SPARK. Tested the Exciter and resistance is very close to spec. Measured vDC from Exciter and got about .5
Checked kill switch and insured everything is plugged in and tight. Should I replace the Exciter? I hate parts swapping but.....
thanks for any input you can provide.

Mike
 
Wow. This one sure is eluding you. The system is pretty straightforward: The exciter charges the CD. The pulser triggers the discharge at the correct crank position. The ignition coil steps it up to a high enough voltage to bridge the gap at the spark plug. And of course the stop switch is there to kill the cd altogether. Can you get a DVA (pulse) reading from the coil primary side (the CD output)? If yes, and it's in the range of about 50-80 volts, the CD is delivering a good signal to the ignition coil. If that's the case, you managed to get a bad coil off the shelf (very rare).
 
understand. just was wondering what voltage is required to "charge the CD" because it seemed pretty low at .4-.5 vDC.
Just to be clear, I would check black/yellow wire coming out of the CD unit to ground, pull the starter rope and measure vDC.
will check and let you know. that is the angle I was working yesterday but wasnt sure what the value should be.

thanks
 
Gunsmoke9150 said:
understand. just was wondering what voltage is required to "charge the CD" because it seemed pretty low at .4-.5 vDC.
Just to be clear, I would check black/yellow wire coming out of the CD unit to ground, pull the starter rope and measure vDC.
will check and let you know. that is the angle I was working yesterday but wasnt sure what the value should be.

thanks
Click to expand...

Almost. Don't disconnect the lead from the CD to the coil, just monitor it. BTW, You cannot use a voltmeter for this check. It is a short pulse, and must be measured with a DVA or oscilloscope.
 
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