so I bought a 90 civic si. It has obd0 ls swap. About 2 days ago while parked and warming up, the car suddenly drops a c.e.l 16, (in addition to codes 14,and6 I believe IACV and ECT). And begins running on 3cylinders. I figured the main problem was because the previous owner "attempted" a wire tuck, and screwed up a lot of wiring. So I bought a. Fresh crx SI harness, and got rid of the wire tuck. After installing all the sensors, I put the key in the ignition, and turn it to its on position, and watch the c.e.l go on, then shut off. I felt Relieved, until I turned the car on, and to my suprise, its still running on three cylinders, and code16. Goes off. Its. Cylinder#4(if that's the one closest to the dizzy). There's no power to this fuel injector. I need help, I know its not the harness because its uncut and almost new. And its not the injector, because I connected the 3rd plug. The. 4th and. It. Began to work. HELP

 

Bump

 

ok, so the #4 injector has no signal? your sure its not the injector itself?
sounds like your ECU just took a crap! This is pretty rare so Before you replace it, compare it to a known good one, or put urs on known good engine.

 

It could be the ecu. Ill have to try a different one. Its not the injector because I switched the plugs around and the 4th cylinder began to work. Besides the ecu, what else can cause this?

 

a break in the wire. that's about it.

 

my mom had a code 16 in the last few days. i asked on here too and everyone said to use a voltage meter to see if its getting the power it needs. i didnt have one. today the car completely didnt start. i took the injectors out (Dual Point) and its clean. the wires are clean..i took my main relay out of my car and put it in my moms car and it started. 10 out of 10 times it started with no codes. so i bought a new one and problem solved (cross fingers).

(89 automatic sedan)

 

Does the main relay have to be for a si? And if my main relay was bad, wouldn't the car have problems. Starting up? Ill deffinatley take a look at the main relay. Also, if its not the main relay and its a break in the wire somewhere. Where do the wires for that injector plug into, to me, it can be not the actual new harness, but the part where you connect the new harness to the other harness that connects to the ecu. If so, do the color of the wires change at that connecting point? Does anyone have like a wire diagram? Thanks

 

the wire for the injectors go to the white plug on the ecu. You could either cut the tape from the wires and follow it to the ecu or just get a voltage meter.

Without Resistor Box


With Resistor box

 

The wires are fine, can it be the resister box? I still haven't switched ecus because all my freinds have obd1.

 

well if the wire look fine and getting connection then i think it has to be the ecu.

 

see if you have continuity between the ground wire at the injector and injector #4 pin A7 at the ecu; wire color is yellow. if you don't then you know the wire has a break somewhere and thats why it's not firing. if you do have continuity however, then that pretty much confirms the ecu for whatever reason isn't functioning properly.

 

Ok, so I finally got my hands on a obd0 ecu. A pm6. Plugged it in, and still having the code 16 run. So I'm going to have to triple check the wires for a break. Meaning cutting all the tape wrap and following a single wire all the way to the injector itself. Ill start from the ecu harness 1st. Due to the fact that its the only factor left.

 

why would you hack up the harness? do a continuity test with a multimeter and see if it shows a break in the wire. if it does, run a new wire. hell, run a temporary wire from the offending injector through your passenger door and directly to the ecu. if the code goes away then there's your proof that the wire has a break.

 

^X2
Continuity FTW
make sure to check POWER and SIGNAL wires.

 

why not take an easy step to swap a main relay from someone else?

 

I can try swapping the main relay, but like I asked, does it have to be a SI one? Cuz if it does I'm assed out. I'm probably the only guy with a ef si in my this small city. I'm going to try what each of you guys had offered for me to do.

 

the fuel pump isn't the issue, the injectors are. changing the relay won't do squat

 

So I bought a tester. And tested fuel injector#4. It had continuity on the yellow wire(the one that runs to the ecu) checked the other wire(wich I think is power/ground) and nothing. So I checked the wires for the 4th time going to the resistor box. And there's no breaks. So what I did was splice injector#1 and direct connected the red/black wire to #1's red/black wire. And then I tested the voltage on both, and all read 6v's on all of the power lines. I then put everything back neatly, reseted the ecu, and turned the car on. NO C.E.L's and all 4 injectors are working. Could it have been the resistor box?

 

hmmm. either one of the wires coming out of the box has a break in it, or somehow internally just that 1 wire failed. strange. atleast you got it fixed though

 

trust me. I found it odd as well. Especially the fact that it was parked warming up. And boom, 3injectors.. what's weird also is that my o2 sensor is not connected. Yet no c.e.l.

 

d16sihatch. my moms car threw a code 16 and one of the injector wasnt getting a signal. i checkd cause i pulled out the injectors and it wasnt squirting. sometimes it starts sometimes it doesnt. i hear it prime like it was on one injector.

i changed the main relay out and til today no more problem.

EFL: doesnt not have to be SI specifically. they are the same as the DX.

 

resister boxes are bastardass nonsensical over complications!
glad you got her running again

 

Thanks guys. I really appreciate your inputs and advice. It would be nice to say, that this would be the last time I need your help. But seeing how my car is a project, you'll be hearing from me soon. Lol