got a 1997 accord with the 2.7 v6. Three of the injectors aren't firing. 2 on the rear bank and 1 on the front bank. All have good power, just no ground on the dead 3. Replaced the PCM and same problem. Is there an input device that controls the ground or is that programmed directly into the PCM. Any help would be appreciated

 

Check your fuel injector resistor box, thats what comes to mind for me at least.

Its a heat sync located near the firewall. On the back right for the 4 cyl, dont know about the v6. That should be the same procedure as well- that is checking resistance between the terminals.

 

The ground side is controlled by the ECM. Check that the ground G101 (see attached) is not loose.

 

thanks redbull, but the ground was clean and tight. The issuenis the ground side of the injectors which is sent directly from the pcm. I cant think of any input devices that would send signal to control the ground. Possible the crank sensor but the car runs, runs like crap, but still runs. When you try and accelerate it just falls on its face and stalls. idles on 3 cylinders. I put a used pcm in and still has the same problem on the same injectors. Unless both pcms had the same issue which is highly unlikely.....ugh, I hate these weird problems

 

after doing some more checking I think it might be the TDC/CYP sensor. Its way out of range on resistance and on the scope its giving no pulses. I know this has a separate crank sensor so its enough to make it run, just possibly in default/limp mode.

 

From my relentless attempts to diagnose a faulty ECU on my own car I've learned it is very rare that they actually go. Even if you beat them up.

Im curious if you tried wiring the injector grounds yourself- bypassing the stock wire to the ECU and see if its a wire somewhere along the line. Or maybe even the ECU connection. Doesnt make sense why only 3 arent grounding.

Heres a learning opportunity for me though. What does the ECU use as reference to know when to ground each individual injector? Is it the crank sensor? Your best bet based on your test is to replace that.