My 1970 1st gen Z project was running great, my technician friend installed LEDs in the dash, and a couple other things- he came upon this part, which did not appear to be attached to anything,mans he thought it was part of an old mod- there was one ground wire going to it. He removed it, and now car runs in idle, but if I drive, it will make it for about a quarter of a mile, then stall dead. Then won't turn over without a charge. What the hell is this piece? Or is it just a coincidence and related to something else?? Please help!!!!!

Does not look familiar to me.  I would guess it is an after-market part.  Looks like a relay with a fuse.

Nothing like that on my car - and I've touched every piece.

That's what I was afraid of. What else could be causing this? Runs fine for a quarter mile, then stalls out. Needs a charge to start up. Alternator and battery just tested fine.

Any help would be most appreciated.

Andy

Somebody took the cover off of a the shunt used on cars with ammeters a while ago and I remember being surprised to see that there was a fuse inside.  Maybe it's an early model shunt?

 

I would guess that it's just coincidence, and that one or more of the "couple other things" that your friend worked on might be the problem.

 

The obvious question is - if he puts it back in, does the car behave normally?  You didn't really indicate if everything was okay until he removed the mystery part.  Also - what did he do with the wire that was attached?  Maybe it wasn't a "ground" but it's powered and killing your battery via short circuit.

 

In general, and your friend should know this, you should not remove parts until you understand what they do.  Especially if there are wires connected.  Also, in general, do one thing at a time.  Confirm that no problems have been created, then move on to the next project.  Now you have the classic " I did five things at once and one of them created a problem" problem.

Of course he checked each thing as he went around- not the first car I've worked on, or he. I'm going to recheck the alternator tomorrow- this seems like the logical place to start.

Andy

Could be that you have a weak battery and an alternator that is not charging.  I would check voltage at the battery with the engine off, then with it on.  The simplest test to see if the alternator is charging.  

 

It may be that he accidentally disconnected the L wire to your voltage regulator.  No L, no charge.  Whatever the reason, if you determine the alternator is not charging, make sure the VR has what it needs to work right before you replace either the VR or the alt.

 

What does your ammeter show before and after the engine is running?  Another tool to use, if you don't have a handheld voltmeter, although not as accurate.

I believe Zed Head is correct. Look at part 18 in this link: http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Electrical/Meters/tabid/1664/Default.aspx.

 

Where exactly did your friend find this part?

The shunt is a 260Z-only part as far as I'm aware, although the carpartsmanual link says that it came on the early '75 280Z as well. Nonetheless, your mystery part doesn't look like a 260Z shunt.

Thank you all so much for your input. I am going to get looking at the alternator tonight- hopefully my more technically minded friend will be there as well. 

-Andy

That part is not a meter shunt, at least not a factory one. The 240Zs all have direct reading ammeters, no external shunt. The 260/280 shunts have two fuses, one on each side of the shunt.

 

The ground wire that was on the mystery part; does it go to ground (car body, etc.) or to a component? Perhaps it needs to be grounded?

Whatever it is, it looks like it's been broken for quite a while.  The other half of the fuse holder and its plastic base are gone.  I notice many mentions of "heat glass" in the various wiring schematics.  Is that Datsun-speak for fuse?  Maybe one of the heat glass parts offers a clue.

 

Since it's been broken, even with a wire attached, it may not have had any function.  Probably a red herring.