FD No Injector Power
 

Looking for some insight.

93 FD
Rywire harness continuity tests ok.
Injector Resistance measures 13.5
Primaries are Mazda 850cc
Secondaries are KG 1650cc

Putting a multi-meter directly into the injector plug - I am not getting any substantial voltage readings either, key power-on or during cranking.

EGI fuse is good
All fuses are good


Wondering what I could be missing.

You wont see voltage checking across injector terminals unless it is firing, the'yre fed constant 12v and the ecu grounds them to fire. check each of the injector harness pins voltage using battery ground as the negative,not across the 2 pins.

Do you still have disconnected connectors under the dash? If so that's the first place to work on.

There is a white and a blue connector that goes from the ECU harness to the dash harness. If those aren't connected you will have weird problems. The white connector has a jumper harness for the fan recall, you can remove that if you see fit (you can read my threads on the topic).

If memory serves, with key on the main power wire to the injectors should have 12v at the connector. Injectors normally get 12v all the time on one pin and the ECU "taps" the other pin to ground which makes the injector fire. More taps = more pulsewidth.

If you don't have the 2 connectors to the dash harness plugged in you may not be getting the 12v for the injectors. I think they are on their own fused circuit and that's how it comes in to the ECU harness.

As stated many people have had problems with those Rywire harnesses so it's hard to say if that could be the problem.

Dale

From the ECU to the injectors there is good connectivity, and I will ground out the lead on one end and check 12v to a ground point when I get home.

The connections under the dash are not lining up - as the harness is a MT, and my dash is AT...... Looks like I need to make a patch harness or some crap.... There are a few threads that can help me with this I have delved into.

I was hoping against hope I could see if the darned thing would fire and run. It's been over a year (Afghanistan) sence I had the car on the road / running.

I'm not quite understanding from your description, but as you know the injectors are supposed to receive +12V fused power when the ignition key is on. I've attached a few screenshots of the 1994 wiring manual that describes this. Page B-1b shows the injectors, and has an off-page indicator note (11) to show that the power source is shown on a different page... I've circled that note in blue.

https://www.rx7club.com/attachment.p...1&d=1519505391



The previous page B-1a shows that same off-page connector note (11) , and the rest of the circuit going back through connector X-05, then to the Main EGI relay, then eventually another connector X-01 and then the 30A Main EGI fuse.

https://www.rx7club.com/attachment.p...1&d=1519505823



This drawing is also in the wiring manual, showing the location of connector X-05. If you don't have X-05 connected the injectors won't get power. It might be possible to have a mismatch between an AT and MT harness; I haven't looked into this because my car was already MT. If the chassis side of the X-05 connector is not sending power to the correct pin of your X-05 engine side connector, that would also be a problem.
https://www.rx7club.com/attachment.p...1&d=1519505823



Hope that helps,
Scott

I don't remember all the details, but I think there are some other important wires going through X-05. You might need connect all of them to make the engine start.