77 280z Restoration

[Av8ferg]

Thanks Steve, I’ll get in there and check on that common ground for these tach bulbs.  I did try and put my multi-meter on the neg and pos sides of the bulb sockets and got nothing,  I even tried put the neg lead on the chassis to get a solid ground.  Did this with the flashers on.  I got zero voltage.  I’ll keep poking around.  Hoping it’s a simple fix.  
That Amazon link you sent is for a three prong flasher, is that what you intended?  
Thanks again

[SteveJ]

14 minutes ago, Av8ferg said:

Thanks Steve, I’ll get in there and check on that common ground for these tach bulbs.  I did try and put my multi-meter on the neg and pos sides of the bulb sockets and got nothing,  I even tried put the neg lead on the chassis to get a solid ground.  Did this with the flashers on.  I got zero voltage.  I’ll keep poking around.  Hoping it’s a simple fix.  
That Amazon link you sent is for a three prong flasher, is that what you intended?  
Thanks again

Yes, terminals B & L go into the stock plug, and you run a ground to the E terminal. It's not that much different in that respect to the EF-32RL. It's just that the EF-32RL has the ground wire coming out of the top.

The downside of having it pre-wired like that is that you need to have the grounding point nearby. If you're running your own ground wire to the adjustable flasher, you can route it to whatever ground point suits your fancy.

Make sure the connector for the tach wiring harness is clean on both the gauge and dash harness sides. The turn signal bulbs are wired to that connector. You might even want to take out the tach and test for voltage at that connector. Back from there it would be the C5 (white) connector.

[Captain Obvious]

So I got a chance to look at the wiring diagram, and here are my thoughts.

First, the indicator lamps in the tach are simply in parallel with the corner lamps. The implication of that is... If all four corners blink with the turn signals, your non-functioning indicators in the tach have nothing to do with either of the flasher modules. It also has nothing to do with the hazard switch.

Steve's thought about the ground for those two bulbs being broken is a good one, but I'm thinking if there was a problem with that ground, the tach wouldn't work either. Depends on where it's broken (if it's broken at all).

So I have a C.O. question... What is the possibility you swapped the turn signal indicators with the tach illumination bulbs? Maybe you have the bulb sockets swapped? I remember you said that you don't care about the illumination circuit because you don't drive at night... I'm thinking maybe when you put a turn signal on, one of your illumination lamps is blinking and you just can't see it in a bright garage? Just tossing out theories. 

And for the hazard issue where only the left side blinks... I'm thinking that since all four corners work fine with the turn signals, then that problem must be inside the hazard switch. I took a refresher look and they do have separate circuits coming out of that switch for left and right sides. So it's completely conceivable that one dirty or deformed pair of contacts could knock out one side of the car's hazard lights.

[Captain Obvious]

I found a pic of the back of the tach installed. It looks to me like they are grounding the turn signal indicators through the tach body and not through the harness? I don't have a tach here loose to verify, but it looks like that to me. That opens up the possibility for some other ideas.

You can also see that they changed a bunch the wire colors on the little stub harness on the back of the tach. So you have to be careful about referencing wire colors since some of them changed at the tach connector:

[Av8ferg]

Okay, good ideas here.   I think you’re correct about be hazard switch contact issue.  I will pull that apart and inspect it and clean the contacts with some Deoxit D5.  I’ll also test the continuity with the switch selected before plugging it back into the dash harness.

I don’t think I have the bulbs  in the wrong position behind the tach.  My tach illumination bulbs work fine.  They’re LED and I see them turn on when I turn on the headlights.  Sidebar, you have to swap two wires in the harness receptacle to get those LED bulbs to work in the tac.  Found that out doing some research.   BTW, I have standard bulbs in the turn signal receptacle.   Here the link to getting LEDs to work as back lights. 

https://forums.hybridz.org/topic/129101-tachometer-illumination-issue-solved/

I think you are both right.  It has to be a ground connection.   I’ll check it out when I get home.  

 

[SteveJ]

If you're worried about polarity sensitivity: https://www.superbrightleds.com/cat/ba9s-ba7s/filter/Polarity_Sensitive,No,93,3463:

I ended up just replacing all of the dash light sockets in the 260Z with wedge sockets. That way if a bulb didn't light up, I could flip it around, and it lit up. Not recommended for the faint of heart.

[Av8ferg]

Well,  cleaned the other hazard switch I had and replaced the flasher and no change.  Both switches and both flashers cause the exact same problem.  Only the passenger side lights work.   Highly Unlikely both switches have the same issue.  Those turn lights on the driver’s work fine when I use the turn signals, so I know the circuit and bulbs are good.  Haven’t got a chance to test the grounds on the bulbs in the tach.  

 

Edited July 22, 2022 by Av8ferg

[Av8ferg]

Hazards fixed.   I pulled all the connectors C8 and C7 and cleaned all the terminals with Deoxit D5, there was some green residue in some of those terminals.   I put the harness back in and now the Hazards are working.  

[siteunseen]

You are the Duke of hazards.

 

[Captain Obvious]

Glad you got the hazards working! And what you found makes perfect sense. I was thinking it had to be inside the switch itself, but that's not true. It had to be either inside the switch, or the downstream wiring until it joined with the firewall harness. Good work!

That corrosion is from your heater core leaking 20 years ago. Most 260's and 280's have some green fuzz growing in those connectors.

[Captain Obvious]

14 hours ago, siteunseen said:

You are the Duke of hazards.

Hahahaha!!!!   I'm totally stealing this.   

[Av8ferg]

Looking for some advice,  Been working on the Z this week with success.  Hazards, Radio installed, lights all working so I was pretty happy until yesterday.   I hadn’t driven the car in a couple weeks as I was working on fixing the above items and general interior work.   I decide to take to car for a short drive.  Total distance was about 3-4 miles but never far from home.   The car was driving great, the best I’ve noticed since I had got the timing perfect and the idle mixture set right,  I got a timing light with RPM and advance capability.   Did this over a month ago but haven’t really driven it any real long distance .  
So, I was driving and all of a sudden the engine began to shutter, it felt like it was cutting out I was at about 3800 rpm when I notice the power loss.   A few moment later the engine total died.   Pulled off into the grass in shame.  Tired to start it and got nothing,   Cranking just produced a fuel light cloud of vapor out the tailpipe. Sometimes it would hint of starting but nothing, would just crank.   I pushed the car to the next neighborhood (sweating my arse off) along the 2 lane road by myself with a 35 mph speed limit and left the car there.   Came back 45 mins later and tried starting the car and it started but ran really bad, very rough as it were misfiring.  Exhaust was still very rich smelling.  I went back home got a new ECU and my tools.  By the time I got there (had kids to shuttle around first) it had been sitting about 90 mins.   I put the replacement ECU in and it started right up.   Began to drive it home, 2 mins into the drive it began to slight misfire again.  Temp was not at the center position on the gauge yet.  By the time I was in my driveway it was running really bad again and at operating temp.  Barely made it into the garage..   

I know the fuel pressure is good. Gauge in engine bay is stable around 35 psi.   Car has a new coil, which I replaced 6 weeks ago and it’s run fine with that one previously. Took it at least 50 miles with that coil.  
 

So what could be the cause,?  Obviously not the ECU because the problem came right back once the engine got hot.  I checked the temp sensor on the head between cylinder 5 & 6 (yes ZX setup with P79 head), it was secure.   I know this popping of will give you a rough runner. 
 

I’m leaning toward a problem with the ignition module.  The E12 type on the side of the ZX distributor.   It sits very close to the coolant hose and was very hot to the touch yesterday.  Hasn’t been a problem in the past but it’s where my thoughts are focused.  Cold the engine fires right up.  I’ve read that there have been problems with these modules at time when they get hot.  
 

Anyone with any good ideas to begin my troubleshooting?