280zx Distributor Swap Troubleshooting

[Dat73z]

Hi all, 

 

I was hoping to get some thoughts on a no spark issue with a 280zx distributor swap. Here is a bit of background and what I've checked so far: 

 

1) Coil is a new MSD 8222: http://www.msdperformance.com/Products/Coils/Race/8222_-_High_Vibration_Blaster_Coil.aspx

 

• I checked +/- voltage going to coil and it is 12v (battery) with ignition key in "on" position. 
• Voltage coming out of the coil and going to e80 module is around 9V with no ballast resistor. 
• Primary resistance in coil measured as 0.7 ohms. 

 

2) Wired up e80 module straight to coil like this: http://datsunzgarage.com/engine/e1280x.jpg

 

• Was getting ~9V to e80 straight from coil. Was thinking maybe it needed a full 12V so wire straight from battery to e80? Don't recall what the stock points coil output voltage was, but I measured the terminals with the same meter and was getting ~1.5 ohms primary resistance minus ballast resistor which sounds correct. 

 

3) No Spark

 

• Pulled a spark plug and grounded to valve cover bolt then cranked, no spark. 
• Spark plug wires are known to be in good order and working (as in pulled off my buddies running car). 
• Spark plugs are all brand new NGK's, gapped to factory specs (don't recall specs offhand but used the FSM). 

 

4) Coil gets really hot with key in ON position for more than a couple of minutes

 

• Hot as in burning skin to the touch hot. 

 

Thanks! Getting really excited to get this thing back on the road. 

 

Bit more background...brand new cap + rotor, 280zx distributor and e80 module are in unknown condition- bought them used and never tested although there is no shaft play and everything "looks" ok. Any easy way to test the ignition module? Buddy might have a spare one I could try, but that may take some time. 

Edited February 29, 2016 by Dat73z

[NewZed]

You either have a short in the E12-80 module or a wire connected wrong.  With the key on and engine not spinning you should have battery voltage on both sides of the coil.  The 3 bolt drop is because the negative post is connected to ground.  Recheck the circuit from the negative post of the coil.  Make sure that "tach sensor" wire in your zgarage  link has resistance.

[Dat73z]

Thanks NewZed- great info as always.

 

The 2 original wires that are coming from the OE chassis wires show 12V and drop to 8V when I only plug in the coil (nothing else connected). 

 

Chances are I'm using the wrong wires at the coil? 

 

One is black/white (positive post). 

 

The other is black (ground). 

 

I'll take another look when I get home tonight. 

[NewZed]

If you're connecting black (ground) directly to the negative post then yes, wrong wire.  Black connects to the distributor body.  Run a new wire from the coil negative to the C terminal on the E12-80 module.

[Dat73z]

Yep, just re-read my post and realized I was completely grounding the coil out. Was pretty tired when I was hooking it all up and stopped when I noticed the coil getting hot...glad I didn't start a fire. 

 

So only 2 wires will run from the coil negative, correct? 

 

1) First wire to the C terminal on E12-80

2) Second wire to tach 

 

I think the confusion also is that I have a really late 73' 240z with a 3 wire tach...need to trace the wire back from the tach and figure out where it goes or run a new wire per the zgarage diagram. 

Edited February 29, 2016 by Dat73z

[NewZed]

I think the confusion also is that I have a really late 73' 240z with a 3 wire tach...need to trace the wire back from the tach and figure out where it goes or run a new wire per the zgarage diagram. 

Yes, that diagram is not for your tach.  Just run one wire to coil negative, forget about the tach sensor wire.  Your tach is on the positive side, don't worry about it.  If you're lucky it will work fine.  

[Dat73z]

Just a quick update- thanks again for the help on this. Wired it up per above and got spark. Motor now stumbles and wants to fire but no dice. Probably need to play with timing and the settings on the triples a bit more.

 

Edit- got it running.

Edited March 1, 2016 by Dat73z

[cdl1542]

Were you able to get the tach running with the ZX distributor? Not sure on your year car, but in my 11/70 I did the swap and the tach doesn't budge. Not sure if there's a way to make it work or if I'll have to change it out or what.