1976 EFI Overhaul

[sscanf]

This thread is kind of old but its a good place to pick things up again. Since I last posted, I had to work through some other problems covered in other threads (vacuum leak through bcdd, bad ignition module, bad AFM). All taken care of now.

Summary: 1976 280Z bought about two years ago, had to trailer it home with the fuel injection in the back hatch. No exhaust (not even a manifold). Body in great shape though.

Here's a summary of what has been done... I'm sure I'm missing something.

• New (rebuilt) AFM
  
• New (rebuilt) ZX distributor/ignition module
  
• BCDD vacuum leak repair
  
• Bad Dog frame rail kit
  
• New (well, used) Slot Mags and Tires
  
• 240Z front bumper (still needs some work)
  
• New Coil
  
• All (7) new injectors (Standard brand FJ707T) and throttle body cleaning.
  
• New vacuum hoses.
  
• New MSA coated header and exhaust
  
• All new brakes (drums, shoes, cylinders in back, calipers, pads in front. New master cylinder)
  
• New Clutch, slave cylinder, boot
  
• Wires, plugs, cap were new via previous owner.
  
• Fuel pump new via previous owner.
  
• New fuel filter. Oil Change. Plugs. Etc.
  
• Lots of other misc small stuff.
  

I did everything myself except install the frame rail kit. The guy that did the welding for me went over it from end to end and said it was in great shape.

Anyway, the news is: My Z is on the road! Runs great! It goes like mad. I have not taken it over 5000RPM yet but it gets to 5000 in the blink of an eye. All of the old problems seem to be gone (no cut outs, tachometer is perfect - not jumpy any more). I still have some roughness when its cold but after a minute or two its smooth.

A while back I replaced the aux air intake with a ball valve which I open about half way when I first start it then shut it off after a minute or two depending on the outside temp. I may try the original aux air again now that other issues have been solved.

BCDD is still disconnected. Temp gauge is not working (neither is the clock). I still have to put the interior back together - I had stripped it before brining it in for welding. Should get that all done this weekend. I'm going to flush the cooling system this weekend in hopes of getting the heat working. Need to work on the bumpers. Get a nice old aftermarket stereo in it. Etc...

Thanks again to everyone on this list who has helped me along the way.

Dan

Edited April 18, 2014 by sscanf

[hr369]

love those slot mags and burnt orange paint. interesting setup on the ball valve. im wondering if you could rig up a 240z

manual choke lever to it. the aux valves that i've had never

really worked. they either stuck open or stuck closed. yours

would be probably the first fuel injected z with a manual choke.

Edited April 18, 2014 by hr369

[siteunseen]

1/4 turn valve on the AAR, genius! Looks like you may have a newer ZX distributor wired in too, I just did mine. Now to the fun part, driving the tires off.

[sscanf]

Yep, I put in a rebuilt 1979 280ZX distributor from Rock Auto ($90 AND it comes with the ignition module!). Fixed lots of problems, including my jumpy tach.

I got the carpet back in it over the weekend - makes a hug difference in cabin noise.

Its my new daily driver.

As hr369 suggested, I am tempted to hook a cable up to the ball valve and call it a day. Maybe after I get everything else sorted out, including the water temp sensor tweak - if the AAR still doesn't work I'll find a 240Z center console and choke assembly and rig up a cable.

[jimbob_racing]

Sorry for asking, but why the 79 280ZX distributor and not on for a 76? Any details on the install? I have a 75 that I am thinking about replacing the distributor on so this is relevant to me.

[sscanf]

Sorry for asking, but why the 79 280ZX distributor and not on for a 76? Any details on the install? I have a 75 that I am thinking about replacing the distributor on so this is relevant to me.

For me, it was mostly because the previous owner had already done the ZX distributor upgrade (but the used replacement was misbehaving causing a jumpy tach and cut outs). It turns out that its a very easy upgrade to do (details here ). I think the original motivation for doing the upgrade is the improved electronic ignition module in this unit. You will also have to replace the coil along with it (about $12 at Rock Auto). Look at that link for details (especially the "this is what it becomes" diagram to get an idea of how simple the wiring is) but, in a nutshell, it goes like this:

1. Disconnect the old ignition module (which is located in the passenger compartment)
   
2. Swap in the ZX distributor (and mount! you might have to get this from a junk yard) and coil
   
3. Do some simple rewiring between the distributor and coil (toss the old ballast resistor)
   
4. Profit!
   

[Zed Head]

I think that sscanf is right, the technology of the system was improved by 1979. The ballast resistor is gone, for example, so more current through the coil for a better spark. Plus, the cost of just the old technology module is more than the newer module and distributor combined.

Same topic though - you could keep your old distributor and wire in a GM HEI module and GM HEI coil for less money (~$25 total) than either for probably equivalent technology. But if you need a distributor, you might as well go with the ZX system. The ZX way is easier to wire in also.

Don't forget to check the advance curves on a new distributor.

Edited April 22, 2014 by Zed Head

[jimbob_racing]

Great info guys! Thanks for the quick feedback.

How exactly do I check the advance curves on the distributor?

[Zed Head]

Without a machine you either have to do some detective work on the parts and part numbers, or test advance while it's on the engine, with a timing light. The weights for the centrifugal advance have numbers stamped on them which indicate full advance level. But the springs determine rate of advance. The vacuum can is hard to to identify.

The parts place distributors have mild curves I believe, so that no engine damage will occur from too much advance. but if you get a factory distributor from about an 81-83 distributor you might get some pretty high advance numbers.

It's one of those dilemmas. One small advantage of the HEI module swap, in that you keep your stock curves.

Some of the members have recently installed programmable electronic distributors from a new supplier, 123ignition. You're in that zone of time, money, and complexity decisions.

[zclocks]

You need to send your clock to zclock.com for conversion to a quartz unit.

Zclocks