72 240z no fire!

[jcox]

I know this has been gone over and over again and is probably getting a little old for those of you that have contributed to solve these issues. But if you're still up for a challenge I've got one.

I picked up a 72 that had several components like starter, voltage regulator, coil, ballast resitor, etc that had obviously been parted out and missing. I replaced the missing parts and wired everthing back from the engine bay harness with a systematic approach to get her to the point of turning over.

Thinking that I had made great accomplishments (being a novice) just to hear the engine turn over. I was ready for the next step of putting fire to the engine and hearing her roar! ("roar"... only because there is no pipe connected to the exhaust manifold).

Keep in mind that I only want proof of fire at this point so I wanted to check fire from coil first and then take it from there. Fire from coil is where I've been stuck for about a week now.

I've read all posts I can find. Followed every bit of information that's been out there more than once and can't figure out what the problem is.

Without going into much detail I've checked the continuity on all the wires according to diagrams and the posts on this issue. Checked connections over and over. I've replaced the coil, plug wires (although only using the coil wire for this step), I checked the Tach wires (even tried a different tach). I have ran a wire from battery (+) to coil (+) and still nothing (I only get the ACC Relay switch click, which also happens with ignition switch). That would leave me to believe it's the coil, but I first tried the coil from the 72 to start my 280 and it cranked right up. I then purchased a new coil but had the same results.

I've checked the grounds to the best of my ability (any specific places to check might be helpful)

The only suspect I have is the ignition switch (although all wires check out when testing according to several post I've read). I say this because it appears to be a newer switch than what I have to compare to. This switch has an all black body and just appears to be newer. It also has 2 black wires that are incased (they appear to be red/blue on other switches I've seen) on the left of the switch body and one of them is a male connector that is not connected to anything nor is there anything to connect it to.

I need your help... please!

:stupid:

[EScanlon]

Presuming that the engine does turn over, I won't mention wiring to the starter.

The coil has a Black wire that connects directly to the distributor from it's Negative post.

On it's Positive post, is a Black with a White Stripe (Black/White) wire that connects directly to the Tachometer. That is the "loop" wire that the Tach uses to sense the spark.

The "return" leg of that Black/White wire is now Green/White and it leads back to the Ignition Switch, except there is a "T" connection that connects to the Ballast Resistor that's typically right below the Coil. (Don't forget about this T connection).

The other side of the Ballast Resistor has a Black/White wire connected to it. This "second" Black/White wire causes problems in that being right by the Coil AND the Resistor, it's not unusual for people to connect the wrong one to the coil. This Black/White wire connects to the Ignition Switch but on a contact that gets power through the switch ONLY when the key is in the RUN position.

Mix the B/W wires up and you won't be getting spark when you're trying to start, and since it won't start, you won't notice that you DO have power to the coil when the key is in the Run position. Only by a quick "quirk" of having the engine still turning over when you release the key might you get lucky to catch everything just right to have the engine "start" and then run.

To identify the right B/W wire to connect to the coil, do a continuity check between the Green/White wire that connects to the Ballast Resistor and one by one the Black/White wires, with the Ignition Switch in the OFF position. The B/W wire that completes the circuit is the one that goes to the Positive terminal on the Coil. The other B/W wire goes to the Ballast Resistor and the G/W wire goes on the other end of the Ballast Resistor.

That corrects the ignition wiring to what it's supposed to be.

To check that you are getting juice to the coil:

With the Ignition Switch in the Run position, you should be able to detect 12v between the G/W and the B/W wires connected at the Ballast Resistor. That is, connect your meter in place of the BR, or check the B/W wire to ground. Alternatively, with the key in the Start position, check the G/W wire to ground and you should also read 12v.

The 2 wires that are encased in a black insulating sheath, are more than likely the "Key-In" buzzer switch wires. If they go to the side of the Ignition LOCK, then that's what they are.

Hope this helps

Enrique

[jcox]

thanks for the info... I'll go through this afternoon and let you know what I come up with.

[jcox]

I appreciate the advice and it gave me more to check but I'm still not having any luck. I've attached a pic of what I have and it should give some detail instead of trying to write everything out.

I think the biggest question is why I don't get any fire at all going directly from the battery (+) to the coil (+). Maybe I'm not doing that correctly... I'm basically running a wire with clips from the battery to the coil and then turning the ignition but all I get is it turning over with no fire?

I've also included a couple of pics of my garage... yes I have a problem!

[EScanlon]

Just from the pics it looks as though it would be ok.

Since you're running points, have you checked that they DO open and close, and that the ground wire inside the distributor is ok. Also check that the connection to the distributor (negative coil wire) is making good contact.

I'll have to ponder this, and maybe others can chip in as well.

E

[1 Bravo 6]

Hey there "E",

Do you think the problem could be with the condenser (I think you'd call it a capacitor)?. That'll cause the ignition systen to fail won't it ??.

Rick.

[jcox]

we have a spark! This issue has been driving me crazy and finally after a week of pulling my hair out I'm ready to move on and try to get this thing running. I'm pretty sure that without the help from this forum... especially "EScanlon" that I would still be spinning my wheels.

The advice that helped me the most was checking the distributor. As recommended by "E" I did check the ground at the distributor (removed cleaned and reassembled and still had nothing). With the known fact that there could have been something at the distributor to prevent fire from the coil I started looking at my options for the quickest test possible. The easiest thing for me was to pull the distributor from my 73z (dual points) plop it in and you guessed it... fire! I've never been so happy to see that little blue spark.

That problem now solved and ready to move to the next one. However that does present a new question and that is what at the distributor is causing the issue? What should I check on the original distributor? I would like to put the distributor back into the 73 and remedy the original (distributor single point). Is it best to just replace it or try to find another used one? Keep in mind that I will probably be selling this car after I get it running and do a few minor repairs.

So to some it up... I had it all wired correctly, checked, checked, and rechecked all wires for proper continuity, new coil, condenser, br, coil wire, checked voltage at all wires etc. and was convinced that I just had some wires in the wrong place. I was convinced that I was just missing something and kept going over it again and again.

This issue is my first post and I'm sure you will hear from me again... I will check this forum first from now on!

Thanks guys!

[bigoak]

Congratulations. Isn't this place great...