New kid needs some electrical help

[usafdarkhorse]

I've perused around the old Z's for some time now and I've found one that I might possibly want to get into.

The seller has a 1976 280Z which has a newer low mileage 83 280ZX motor installed. Great. Fine. Except for one thing. Apparently the car needs a new wiring harness, so when the motor was swapped, the mechanic for the guy rigged the car to start and it does and runs exceptionally, but the turn signals and most of the gauges DO NOT work. The speedo and voltmeter both work and so do the hazards, cabin lights, headlights and tailights.

Question. What am I getting myself into here? I talked to a Z specialist here in TN and he says that the 83 and 76 L28s were vastly different as far as fuel injection, alternator, and mechanics is concerned, but he'd have to see the car to know what needed to be done. I'm not sure which wiring harness I would need and to what extent I need to go to have all the gauges, lights, and engine mechanicals running like clockwork.

Anyone have any suggestions?

[Nissanman]

I wouldn't have thought that it would need very much done on it to get all that stuff working again.

You are probably only needing to deal with an incompatibility issue with the engine gauge senders and the existing wiring harness connectors and gauge characteristics.

For the gauges, maybe it would be more desireable to fit mechanical replacements.

I personally prefer mechanical gauges to electrical anyday.

If you wish to retain the existing electrical gauges you may need to retro fit the senders that were designed for the original 280Z engine, i.e. non-EFI stuff.

That is not a big deal.

Providing the wiring is still intact, once the senders are replaced all should be well.

As for the indicators, you will just have to do some fault finding of the system.

Do a methodical check of the entire system, power, relay, wiring connectors, column switch etc.

There is a member on this Forum who re-furbishes the stalk switchgear if that is found to be cactus.

Bottom line: I wouldn't let the faults you listed get in the way of a good deal.

My '73 240Z had an L28 EFI engine fitted to it when I bought it [with twin Hitachi/SU carbs] and it went like a scalded feline, auto trans and all:devious:

[ktm]

For most of the gauges you can simply run wires directly from the senders to the gauge. Screw trying to retrofit a harness. As long as you have a wiring diagram and understand what the requirements are for each gauge, you can recreate a harness. If you have the patience, understanding, and, most importantly, desire.

[usafdarkhorse]

I was talking to some Z guys on another forum and they were saying that it wasn't a huge deal as well.

Do you think it would be a good idea to get a '76 harness and use the bits off it that needed the appropriate wiring?

It does sound like an incompatibility to me. I will probably have to go circuit hunting because the hazards work but each individual signal does not.

Are the gauges for the '76 Z electrical? Everything but the motor and tranny is the original car, including the gauges I believe. Does this make my problem any different?

It really is a great car. Just needs some time spent on it.

[Nissanman]

I may be wrong, but I don't think you need a harness.

Unless the one in the car has been damaged or butchered, [no reason to suspect this] all you need should already be there.

The hazard flasher proves that the wiring and power is sweet in that respect.

The turn signals however use a different relay.

Each relay is a 2 pin device.

Hazard relay wires are GW [Green/White] and BL [black/Yellow], turn signal relay wires are W [White] and G [Green].

I think:nervous::nervous:

The relay or the indicator switch gear may be the problem.

Switch the hazards on and trace where the relay sound is, the turn signal relay is probably close by it. It might be as simple as a harness plug not fully inserted. If you have some electrical knowledge and a decent Multimeter, should be relatively easy to find and fix.

Factory instruments on the Z's are electrical.

If they are all intact and we make the assumption that they are indeed operable, it will only be the engine senders that are the problem.

If you determine a problem with the harness, simply run new wire as mentioned above.

You will need the correct tools though and a decent wiring schematic applicable to the vehicle.

I have the Haynes Manual and the schematics are absolutely AWFULL to read.

I could scan it and eMail it for you if you are really desperate:rolleyes:

[280z1975]

You can find the 76 wiring schematic here:

http://www.atlanticz.ca/zclub/techtips/electrical.htm

in PDF or jpg.

[sblake01]

The harness doesn't have to be changed. What need to be changed are the engine mounted efi components and anything on the engine that has to do with the 76 guages. You probably don't have an intact 76 engine lying around but the easiest fix would be to find one and swap out any of those components on the 83 engine that are different. There a quite a few. The turn signals would have to be a separate problem as they are not related to the engine.

[Fun_in_my_z]

And those may be as simple as cleaning the contacks or the switch.

[usafdarkhorse]

Hey thanks for all the suggestions guys.

I went to see the car today and it's not as bad as what his son was making it out to be ( his son is the one selling the car but his dad knows the specific details).

He seems to think that the cables and everything is all there, but it may not have been hooked up right or may not have been hooked at all. His recommendation was to go through the compartment and try to find cables that are not plugged, but if I need to find relays and such, I have a friend who is very proficient in electrical systems and he has a good multimeter. With both our heads we should be able to figure this stuff out. :stupid:

The seller cleared up some info though on the fact that it is an 83 motor, but it is running on the 76 harness and ECU.

What sort of components would be needed from a 76 to make the gauges work if the hookups are not the problem?

[Nissanman]

Possibly the only changes you will need to do will be the oil pressure sender and the coolant temperature sender.

[sblake01]

You'll likely need to use the 75-78 thermostat housig as well as the 75-78 sensors that go with it as well as the oil pressure sender. The 83 thermostat housing is different and I don't think the earlier sensors, i.e. thermotime switch, thermal transmitter, and water temp sensor are the same. Didn't the 83 have digital guages?

[usafdarkhorse]

I think some had digital and some had analog.

I believe all those parts you mentioned were carried over from the 76 motor to the 83 motor from what the seller is telling me, but I can't be sure. He says he's built 5 Z's himself and that the cables and wires are all there but that there may have been on open ground upon hooking it up and everything may not be hooked correctly. He personally thinks that the gauges aren't getting power one way or another, not necessarily that their sensors are not hooked up.

Really the only way to tell is to get down in it and look.