Datsun Roadster Forum-311s.org

HELP, I just installed my engine after about 2 years of disuse. Had the alternator rebuilt, new battery and starter checked out. When all is done, NOTHING happens when I turn the key. The brake lights, horn & S/Brake switch work, but that is all. No other wiring has changed. Any hints?

Almost sounds as if the engine is not grounded to the frame.
Is the ground cable installed from the frame to one of the mounting bolts of the starter?

After ensuring your motor is grounded well:

Check the cable from the battery to the starter, make sure it is not pinched or broken. Make sure there is power to the starter (12V at one of the solenoid posts). Make sure the signal wire to the solenoid gets power when the key is turned to 'start' (the male tab with female wire on the solenoid). Make sure both terminals of the solenoid get power when the solenoid is actuated. Check that the starter gear is not jammed.

That should get you passed the point of nothing happening...TR

OK, here goes.. The battery is grounded to the block on pass. side. Ground wire then goes to frame, then the inner fender (using voltage reg. screw). Alt. is grounded to frame on the other side. I have power at the starter post, and I remade the pigtail that goes from the starter to the three pin plug. If I cross the starter post to the spade connector on the starter, the engine turns. (intake manifold is now out of the car to make access easier). With all of the connectors plugged in, I have no juice at any of the pins at the ingnition switch. The wiring diagram that I have shows a W/R wire going from the ingnition to the volt. reg., but I don't appear to have that wire. There is one fat W/R wire at the ignitoin switch, but I cant seem to find where it goes. I haven't changed any of the wiring since it ran last, other than replacing a few worn connectors. I am at this point ulling my hair out. I appreciate any and all of your help. Hope to see you motoring some time soon.

What year car are we talking about?

You are on the right track, there should be power to the ignition switch.

This sounds like the ill-fated under dash harness burn...

You can try establishing which terminal is supposed the be the + on the ignition switch and run a fused line from the battery to see if that energizes the whole system.

Make sure you are not setting yourself up for a dash fire, though! TR

This is a '69 1600, no smog. Would the next step be to strip back the wire wrap and look for a cooked wire? That is what it seems like. I figure I ought to have something at the switch. By the way, I don't have a ground from the starter bolt to the frame as I figure that the one from the block to the frame covers that base for me.

Normally something spectacular happens under the dash before the wire becomes completely severed. You can try tracing the wires back from the amp gauge to the fuse box, checking if you find crunchy or warm spots. You should have fuses on the lines to the amp gauge to ensure you have protection against this hazard. You may want to check the fuse box one more time and double check the connections you changed as having no power to the switch is weird, even if the harness is fried. That implies a dead short which should give some sparks if you tap the battery lead to the terminal...TR

OK, so now it's back to the garage. I will let you know how this works out.

Thanks again.

Hey, no problem. I have to be away from the computer for a few hours, but I think if you find out why you have no power at the ignition switch, you will find all of your troubles...Just trace it back and forth! Good luck! TR

OK, back to electrical 101, and I keep going back to the Alt because it is the only thing that has been worked on. With all of the wires disconnected from the alternator except the ground, I measure 0 resistance form the frame to the ground lug (thats good), but I also measure 0 resistance from the frame to the positive terminal. Is that right?

The wires under dash all look pretty good and my new connections all check out.

It has been a long time since I have seen a stock alternator and wiring. I do not know how they respond. When it is unplugged, do you have 12V at the ignition switch? Are you sure there are no blown fuses?

You are right to think that something new may be the cause...Sorry I cannot be of more help, TR

None of the fuses are blown. I just did an Ohm test with the battery disconnected. I seems to me that the hot and ground sides of the alt should be isolated and therefore have infinite resistance, not '0'. I'll try to check it out on another car. Time to keep chasing wires. I think I need to hire a Leprechaun to do the under dash stuff. My neck is getting sore.

OK, one last shot for now. Does anyone know if the car would turn over, or even get juice to the ignition if the four wire connector and positive wire were not connected to the alternator? I think I will take the alt out and bring it to a different shop and have it checked out.

Again, I thank you for your time and patience.

You should be able to run the car on the battery only for a short period of time.

Do you have power to the ignition switch with the alt unplugged? Without power to it, nothing is going to happen regardless of the alt.

Another one that pops up from time to time, make sure all of the leads to the fuse box have power. Sometimes there are issues at the fuse box so that even though both sides of the fuse have power, the wire coming away does not...

TR

OK, everything seems to meter out OK. If I run a hot wire from the battery to the positive post on the alt., then I get my lights and ignition back. I can easily add this wire, but I don't understand why I should need to add a wire. It is possible that I put in the wrong alternator ('67 instead of '69), would that mess things up like this?