wes3015

I have a problem with my 2003 civic si and not sure where to go from here. Getting ready to admit defeat and bring it to the dealership. The car is completely stock, no modifications what so ever.

How it happened:
I was just driving along on the highway at about 60mph and felt the engine start to miss. I drove it home and parked it in the garage, check things out over the course of a few weeks, didn’t really put much work into it. Then all of a sudden one day I just go to move the car out of the garageand it works fine. So, I drove it regularly for about two months, before it happened again, and the problem is there permanently now (in my experience, this would seem to be some type of electrical or electronic problem, i.e. wiring, computer or sensor).

Now, the car will start and run, but only on 3 cylinders. I’ve determined that the ECM is not sending a signal (ground) to injector #1.

DTC’s:
P0341 (Phase Gap) is showing, I’ve ran through the troubleshooting for this in the service manual with the exclusion of checking timing chain and VTC actuator. I may be wrong, but I just assume that this would not cause the symptoms I’m describing, no ground to just 1 injector.

P0134 (A/F no activity) this didn’t show up with the problem right, only recently since I’ve been testing things

What I’ve checked/done so far:
-wire going from ECM to injector #1 (continuity check, OK)
-power to all injectors (yellow wire, all OK)
-coils, swapped them around (all OK)
-spark plugs
-replaced injector #1
-replaced CMP Sensor A
-used a jumper wire to manually fire injector #1 while engine idling (I know it sounds crude, but it proved that the cylinder was getting fire, and compression and valves ok) the engine ran fine while I was doing this

It’s also interesting that when I noticed injector #1 not working, I swapped it with injector #2, and determined the injector was sticking and rarely working. So I replaced the injector, having proven it was faulty. I have funny feeling that whatever happened to damage the injector is somehow related to the root of my problem.

I would appreciate any ideas or recommendations. Please help, I really don’t want to bring it to the dealership.

turboteg2nv

Have you tried swapping ECUs with a known/working ECU?

Also, welcome to the site.

wes3015

No, I didn't. Unfortunatly I don't know where I can get one without buying it, and I would like to exhaust all options before buying anythig else.

However, I did pull the cover off my ECM to inspect for anything visually burned out, I couldn't see any obvious damage....but that doesn't eliminate the ECM as the root cause of the problem.

But thank you for the suggestion.

turboteg2nv

Not sure where you're located, but if you post in some local car forums you might find someone who has Kpro installed. You'll need to use a Kpro'd ECU to avoid having the dealer reprogram the key (anti theft device). I'd imagine someone in your area would be willing to help you out if you buy them some beer or something.

I'm out of other ideas based on everything else you've tested. You have fuel (assuming the rail isn't clogged on #1 injector??), you have spark (assuming the timing is correct)...it should be running.

josh's ep3

Yeah, it looks like you've covered all the bases. Any recent, major maintenance done?

wes3015

Yeah, I'm realy running out of ideas...I'm going to go through everything one last time and then I may follow your advice and try to find someone locally that may want to lone me a ECM. The car is pretty rare where I live though, I'd estimate only about 6 in the city.

The rail is definetly clear, I had it all out when I replaced the injector, and cleaned it well before reinstalling. As for the timing, I never checked it yet, bet its next on my list.

No major maintenance work done latly either.

Thanks guys