To start I bought this car last week so this issue is new to me as are Hondas in general. It's a 89 honda civic sedan stock everything 1.5 dpfi. It's throwing code 16. I re soldered the main relay as well as tried swapping a new one in. The aux injector does work but the main doesn't. The main will work with the aux plugged into it but neither will work with the main plugged into either. I also tried a different ecu to no avail. It runs off the aux in limp mode and won't go past 4000 rpm. While running I checked and I have power on one wire at the main plug so idk what to do now

 

I forgot to mention when i bought it it wasn't running we found the screw for the rotor in the cap and it was 180 deg out. So idk if that happening while running could fry something else

 

Well if you have power on the primary injector that's a good sign, but now you need to see if there is a pulsed ground going to the other wire. Either you can pick up a noid light or grab a 194 bulb and straighten out the pins then put the bulb into the connector. You should see it flash if there is a pulsed ground and a constant power on that connector. If no pulse, check to make sure you have continuity from the non power wire all the way to the ecu. Sometimes the wire breaks after the pin so you may need to pierce the wire to get an accurate reading.

 

I have power at both but only the aux injector will fire. Does anyone know which pin on the computer goes to the negative wire on the main injector?

 

A5 & A7 are both primary injector signals

 

I jumped from a2 to the main injector wire that doesn't have power. When I did that it still threw code 16 and wouldn't start at all. Normally it starts in limp mode

 

Does the ecu send identical signals from both of these pins? If so where do they tee together since there is only one wire at the injector for ground