Banth280z

After years of lusting after the majestic beast that is the s30, I finally managed to track down my first project in a pair of '77 280s. Unfortunately I've hit a wall in the resto. Several things in the electrical system aren't working as they're supposed to and I'm not sure where I should be looking for the problem at.

The problems I'm having are as follows:
Both leads to all six injectors are hot all the time
Very weak current to the fuel pump, not enough to make it run.
No current anywhere on the fuse panel under the dash.

As far as I can tell, no fuses under the dash are blown. I've also upgraded the fusible links to maxi-fuses and redone the battery cables. Everyone on this site seems quite knowledgeable and friendly, so i thought here may be a good place to look for answers.

Thanks for taking the time to read this, and if I can get these issues worked out I'll try to document the resto here.

zxguy1986

Welcome to ZDriver!

You have the FSM - or you can download a freebie from XenonS30 . Check out the other docs there. Very useful.

Your FSM (factory service manual - "Old Codger"!) has a pile of inspection and troubleshooting pages. They are easy to follow.

Check out the electrical diags. Could show you how the car was wired at the factory before your previous owners renovated. You may find a clue. Also you may need to get yourself a multimeter and learn how to check circuits with it. Great tool for searching out electrical issues.

Meanwhile, hang out for input from our S30 pros.

Thanks and welcome!

Banth280z

Wow, thanks for the wicked quick reply. I've looked over an FSM posted on another site and it was Greek to me, although it's very possible I wasn't looking at the correct manual and plan to give your resource a go as soon as I can get it unzipped.

I've also downloaded the colored '77 wiring diagram from Z Tech Tips Electrical (AtlanticZ.ca) and it's been helpful in cleaning up some of the "work" the previous owners and small rodents had done to it.

One thing I'm wondering is whether the ECU being bad or from an incorrect year could cause issues like this or if it's more likely that I have wires crossed/cut/corroded ect. Your help is greatly appreciated.

rogerz

you don't look for current you look for voltage. you need to bone up on electrical circuits and learn to use a vom. don't get some fancy digital model it will just get you in trouble if you have no experience with one. a cheap analog will do everything you want for circuit/continuity issues.

PredatorZ

The fuel injection on these cars is common pulse, so that might be what is throwing you, they should all fire at the same time. And no need to worry about mixing up the connections, it doesn't matter. Just thought I would add that.

Pez

I would check your ground to the EFI system. Remember that EFI is a completely separate and independent circuit than then rest of the car. Nothing in the EFI system goes through the fuse block.

The FSM is a bit over my head, but everthing made sense when I found this one:

http://www.atlanticz.ca/zclub/techti...ectionbook.pdf

That is a manual that deals with just the EFI systems, and refers to the FSM. I started stripping back a few wire looms and found that all the wires in my 76 were numbered on the insulation, and matched the numbers in the pdf I linked to above. Then I figured out I had no ground.

Banth280z

Hey guys, thanks for the responses. Hopefully I'll be able to find a bit of time to work on it in a few days and let you know how it goes. In the meantime, a thank you to PredatorZ and Pez for the great info and resources.