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Jeff Berk

Trouble-shoot directions for ignition/no start

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this morning I tried to start my 260z and the engine turned as normal, then I remembered to pull the choke, and nothing. I tried again and it once again turned not start. I released the key and tried again (it was a cold morning) and nothing. Again, nothing, and again.

Where do I start? The battery seems fine but I put it on charge anyways. I didn't even hear a solenoid click (although it might of been muffled by my panic).

Should I start at the ignition, solenoid, or is there something obvious (or insidious) I need to look at? BTW, it likely doesn't matter but I have a Mallory Unilite ignition. 

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 Start by determining if the problem is lack of fuel or spark. Pull a plug, reattach the wire, ground the plug and have a friend try to start it while you're watching the plug.There's several ways to check for fuel. I like to pull the dome and piston from the top of the carb. then pull the choke. The nozzles will drop and you should be able to see fuel above the nozzle. You could also pull a fuel line forward of the pump and crank the engine over or pull the float chamber lid.

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2 hours ago, Jeff Berk said:

it likely doesn't matter but I have a Mallory Unilite ignition. 

The Unilites have been known to fail.

When did it last start?  Dies it pop or try to start or is it just complete silence?  "no start" is very vague.

Try starting fluid.

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Addressing the above questions... 

It has sat for 2 weeks outside while I worked on another car. It cranked lively like there was not problem other than forgetting to pull the choke the first time. Then utter silence when I turned the key. I hooked up a charger and it indicated that the battery was at 75% and I hit the "start" button on the charger to give the car more power for an attempted start. 

I turned the key and utter silence once again. The engine did not turn, the starter did not spin, and I don't think I even hear the solenoid click.

The Unilite is a common problem but wouldn't of stopped the starter from spinning the engine, nor would a spark or fuel issue.

Edited by Jeff Berk

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You didn't elucidate the fact that the engine stopped turning in your first post.  Sounds like a dirty battery terminal.  Very common.

Or a bad ignition switch.  Not uncommon.

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Here's where I'm at now.

1) battery is charged and the battery post clamps are tight.

2) the ignition switch tested out fine except there was no continuity between the two red wires with the key inserted or in any position.

Could this mean the ignition switch is shot? Is it repairable? ignition switch.jpg

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I repaired one once.  It depends on what's wrong with it.

The two red wires are for the steering lock switch.  You want to test between the pins on the end of the switch, using the chart with B, S, IG, and A.  The circles with a line between them indicate when there should be continuity.

You can also plug it back in turn the electrical part alone.  I had a switch that would not turn the electrical part far enough.  I had to twist the rod between the mechanical and electrical parts.  Take the two screws out and use a screwdriver to turn the electrical switch.  You'll see the little flat rod that turns it when you take it apart.  You might have to destroy one of the screws, Nissan made them one time use as an anti-theft measure.

image.png

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The pins tested out correct as per the diagram. I jumpered the solenoid to the battery and the starter spun like a champ. 

I connected a multimeter to the wire that connects to the small connector on the solenoid and it showed no power when I turned the key.

I'm assuming that the two red leads don't need to be connected for the starter to start because I didn't bother since they only works the steering lock.

My next step, I assume, is to see if power is going to the ignition switch. I have a wiring diagram so I'll start tracing.

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If the "fusible link" that connects battery power to the wiring harness has failed or if the connectors between the "fusible link" and the wiring harness have opened/pulled apart, that will produce what seems like a total electrical system failure (no cranking, no lights, no horn, no nothing) even though the battery is fine.  Just found/fixed this problem on my 71 240z with the kind people of the Help Me! forum.

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Kenward1000... Thanks for the suggestion. I'm currently working on a G35 in my garage so when done, I'll push the Z inside and take a close look. I looked at the fusible link; however, not at the wiring harness...Jeff

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I'm not sure if this is the ultimate source of the problem but following Kenward1000's suggestion, I think the problem was the connections on the fusible links. I cleaned them up and the Z's running again. 

Unfortunately, one of the solder joints on the gray link is loose. The wire is too dirty to re-solder so I was going to cut the blade connection off and install a new one. It looks like 0.33 inch (8.6 mm) wide which I haven't been able to locate.

Any idea where I can find a suitable connector?

Happy Turkey Day Everyone

Jeff

Edited by Jeff Berk

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My issue was the connector on the wiring harness side of the fusible link had a broken off locking tab.  The connectors stayed together only via friction and had become disconnected.  Couldn't see the disconnect at first as DPO had put a wrap of duct tape around it, in lieu of replacing the broken connector.  

The consequences of having that fusible link fail while on a road trip are so high that I bought a new spare fusible link.  Also bought a new wiring harness side blade and plastic shell.  Didn't need to replace the blade, which is 8+mm in width, but I did have to destroy the old plastic connector shell to install the new shell.

I got these from Banzai Motor Works www.zzxdatsun.com  $15 for the WH03 fusible link and $7.50 for the WH03/05 connector.

Hope this helps.

IMG_5511.jpg

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