Not starting - No power to coil

Does this apply to your circumstances?

https://www.msdignition.com/forum/showthread.php?t=344

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I didn’t know you have this forums (I wrote an e-mail to support, but I’ve never got an answer back). Anyway, I have a question here for 6AL+Blaster2 with Pertronix Ignitor.
I’m using Pertronix ignitor with BOSCH BLUE coil with my ’74 Lotus Europa TCS (Originally, it had a mechanical point with standard coil for 4 cylinders motor). Before I modified for 6AL, the Pertronix wire (red/black) was directory attached to coil’s positive and negative. Positive side of the coil also attached to switched 12V (from ignition key) and the negative side is attached to voltage base tach. (Again, originally, it uses current base tach. but now it has standard voltage base tach. that means, the switched 12V is directory from the ignition key instead come through tach. originally) Now, I’ve got 6AL, I use the schematic graph “AFTERMARKET COMPONENTS Wiring to a Pertronix Ignitor Kit” from the instruction manual. All wirings are correct and all connectors are brand new (I cut all old connectors and put new ones to make sure I don’t have any bad connection). I tried to start the motor – nothing happens, no spark. So, I used the “white wire spark test,” from the manual. Indeed, I have nice strong sparks on the distributor code when I remove the white wire from the ground. I put the white wire back to the Pertronix’s black cable. But this time, I keep the end of the distributor code as is 1/2” from the ground to check the spark with Pertronix. I crank the starter – no spark at all (I’ve tried with both my original BOSCH BLUE and BLASTER2 coil, but it’s the same thing). It looks like 6AL doesn’t pick up a trigger from Pertronix. So, I switched back to my original wiring without 6AL/BLASTER2, everything is fine, my motor runs normal. Again, all wirings are right and all connectors are secure (including cylinder select in the black plastic cap). I have clean 12V on both heavy red and standard red – I checked with a multi meter. Is there anything I can try? Thanks in advance.
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#2
Old 08-25-2003, 03:49 PM
msdtech3 msdtech3 is offline
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The wiring diagram that you used for the Pertronix Ignitor is correct. Since the 6AL is firing while you are false triggering the unit that would tell me that it is hooked up correctly, the 6AL is working and the coil is working. I do agree with you that it appears the 6AL isn't getting the trigger signal from the Pertronix but this could be due to a loss of voltage while cranking the engine. Check the voltage on the small red wire and large red wire of the 6AL as well as the red wire of the Pertronix while the engine is being cranked. I would also temporarily take the small red wire of the 6AL and the red wire of the Pertronix and use a jumper wire to connect them directly to the battery positive for testing purposes. If the vehicle runs then it is a voltage problem during cranking. Also, if the vehicle runs you will have to disconnect these two red wires from the battery to shut off the engine.
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Old 08-27-2003, 07:52 AM
foyc foyc is offline
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BINGO!

I haven't checked the voltage on the small red wire while I’m cranking (it's hard to check by myself), but I hooked the red wire directly to the battery terminal as you suggested from the first shot. – IT WORKS! With a single snap of the key, the motor start running. I don’t know why the voltage drops when I crank the starter, so, I checked the diagram of the car. The original wire on the coil’s positive comes directly from the ignition key switch, but before that, it goes thorough a fuse (shared with many other electric components), and before that, it goes through an ammeter (more over, the other side of the ammeter goes to the battery but the one hooked the fuse side is attached to the alternator). – this might be the reason. I think I will use a relay to solve the engine run on problem, that is, use the switched 12V for the relay signal to switch the line between the battery and MSD small red. Anyway, many thanks! I have this weekend’s project now :-D.
I will post the result with the small red wire voltage information after I’m done.

Thanks again.

Originally Posted by Rusty67
Try to make the coil spark manually. I believe if you ground the negative momentarily it should spark.

Click to expand...

ebelizard Quote:
grounded the coil to the frame, didnt spark.

Click to expand...

If you have 12V directly from the battery to the pos side of the coil and you did not get a spark when you temporarily grounded the negative side of the coil, then it is a bad coil.

Did you disconnect the negative wire from the Pertronix when you performed this test? If not, it's possible a ground potential was preventing the coil from delivering a spark. Remember that you do not get a spark from the coil when you apply power to it... it's when you REMOVE power from it and the built up magnetic field collapses. Make sure you are using a clean ground to test the coil. Preferably another wire from the neg side of the battery.