Previous owner = electrical issues

[IdahoKidd]

Previoius owners are unbelievable, are they not?

I've been chasing a no spark no fuel problem with intermittant success but I may be on to something. I have had power to the fuel pump and to the injectors at the clips regardless of key position. Undoubtedly wrong. What I have discovered from the two cars setting side by side is : there are two red wires that come from a loom that crosses the front of the car to the driver fenderwell. One of those wires stays red, the other goes some 18" and then becomes two blue and one black wire and continue in the loom. Which wire goes to the positive side of the battery and which to the negative side? The previous owner had the multiple wire connected to the positive side and the single red wire connected to the negative side. Both wires are the same gauge, probably 10. The donor car has that going to the negative side adn the single red wire going to the negative side. Both cars have had new eyelets put on so neither is factory and therefore no sure way to tell. The book I have says NCA, which I take to me no color available. With the wire that becomes multiple wires connect to the ground side, the power is gone from both sides of the injectors and the fuel pump works in the crank cycle. It does not seem to work in any combination of unhooking the oil sending unit and moving the flap in the air flow meter. I have also lost spark to the from the coil but do have keyed power going to it. I do not have any power to either side of the injector clip either. There is power to the cold start valve, not power to the plug at the afm. UGH! I have been at this almost 10 hours today. I am open to whatever tests you might suggest. Whatever it is is simple. Expensive perhaps, but simple.

Thanks,

Leonard

[Walter Moore]

Leonard,

I can't really help because I don't have a fuel injected Z, but by replying to your question I am "bumping" it back up to the top of the list on the home page. Hopefully it will stay on the recent list until SBlake or one of the other people with fuel injection experience see it.

I suspect that the fuel pump is not supposed to run even with the ignition on, unless the engine has oil pressure (Indicating that it is running) or you are cranking the engine.

By the way, what year Z car do you have? Mentioning that detail helps everyone involved to hone in on the answer that you seek.

[sblake01]

Leonard,

I can't really help because I don't have a fuel injected Z, but by replying to your question I am "bumping" it back up to the top of the list on the home page. Hopefully it will stay on the recent list until SBlake or one of the other people with fuel injection experience see it.

I suspect that the fuel pump is not supposed to run even with the ignition on, unless the engine has oil pressure (Indicating that it is running) or you are cranking the engine.

By the way, what year Z car do you have? Mentioning that detail helps everyone involved to hone in on the answer that you seek.

His is a 77. The oil pressure signal is only in the fuel pump circuit on the 78 and up cars. I posted the chart for his car in another thread. The problems are obviously caused by the previous owner and since I have no idea what was actually done, I have no suggestion other than to compare what's there to the wiring diagram and try to correct it which is what I think he's doing.

[IdahoKidd]

The two wires in question are the ones that apparently go from the battery to the harness that crosses the firewall near the hood latch. The the wire on the left (has the eye, then a connector), is red, goes a foot or so and morphs into blue and black wires. Does it go to the positive or negative side of the battery. The other wire (has a white connector)is red and remains red. Does it go the positive or negative side. With them both unhooked, I have crank, I have fuel pump during crank, I have headlights, but I DO NOT have the gen light, or wipers, fan, etc. I have most of the mess unraveled and put back to original, knowing these two are correct will get me going a long way.

I have read literally hundreds of posts, gone through the repair manual file and have looked at all the related photos I can find. I am certain it is so simple that it is assumed everyone knows.

Many thanks!

[sblake01]

I'll have to do a little research on that one. I have a 78 which is a little different.

[IdahoKidd]

The previous owner had the fuel injection harness wired backwards; putting power to the ground side, grounding the power side.-still have power to both sides of the injector plug on the engine.

A loose ignition relay on the passenger side lit up the rest of the fuse panel (it must be grounded, not just hanging by the wires).

Still no power to the two top left fuses in the panel (they say light left and right) but all the lights work on the entire car. In fact, everything works, except it won't start.

It has the match box type distributor and tons of spark

If fires and briefly runs with starting fluid

The fuel pump works like it is supposed to (changed out AFM with donor car-took right off). Pumps on crank, pumps when key is on and lever moved at AFM.

I am tired and I give up. 20 hours without much to show for it. All of the wiring is back to original to the best of my knowledge and resources.

Any chance the fuel injection module (large black unit on kick panel left of driver foot) is ruined because of reverse polarity? I switched out donor box but prior to discovery of reversed wires and I may have cooked it too.

Time to go seek professional help.......

Thanks,

Leonard

[sblake01]

Matchbox? As in E12-80 module on the side of the distributor? That's not stock on a 77 or any other S30 but many have done the conversion but it has to be done right. That could also be part of your problem(s). A stock 77 would have the much larger E12-27 ignition module mounted on the passenger side kick panel just above and forward of the fuse box and nothing on the side of the distributor. And what you're referring to as the "fuel injection module (large black unit on kick panel left of driver foot)" is the ECU (electronic control unit). I don't know what reverse polarity would do to it because I've never been through that.

[IdahoKidd]

I really appreciate your time and your information.

Here is more of what I know. The previous owner died while trying to make the car run better. It ran when it was taken to him, and the more he worked on it, the worse it ran until it didn't run at all. He replaced the entire engine (??) trying to make it run again and never got it accomplished. The engine in the car had the distributor you see in the picture. From what I can find, it is referred to as the "matchbox" and came from a later zx. The base is the one for that distributor, at least it is different than the other two distributors that I have. Neither of those work and I suspect dead pickup coils. This one is hooked directly to the positive and negative side of the coil, bypassing the voltage reducer and produces huge spark.

The other pictures are of the ecu and of the ignition control (?). Both are identical to the 77 donor car and I have swapped both back and forth without success. While I am unsure of how the distributor affects things, I am almost certain the injection system isn't firing or grounding or working however it works correctly. Both sides of the injector plug have power to a test light and do not blink. The cold start valve sprays when tested and that plug has pulsating power.

Is there a test to check current at the ignition control (passenger side unit) that will tell me about circuts or lack of power or ??

Thanks for your time

Leonard