I have a misfire that seems to be at the injectors. I am running a wire-in e420d that i have driven on street and track for about 10k miles over three years. I had the engine rebuilt recently, and after getting about 100 miles on the break-in, the sputtering/misfire began. I towed it to my shop for diagnosis and am noticing that for injectors 1 and 3, the voltage intermittently drops to 0-1 volt, about when it is sputtering. Injector open circuit check was set to "none" at the time, but now that i know what it does I have set it to 1,2,3,4 and tested it again. No protection methods kicked in. I am wondering if this could be the +12v feed to the injectors that is causing problems or a ground issue? I can't seem to think it could coincidentally be both injectors failing, or if that would even show up under injector voltage. Any help is appreciated. Thanks in advance!

 

Hello Ravingracer,

Could I ask you to send a log of when the engine misfires and send this to tech@adaptronic.com.au together with the current copy of your ECU file? It would be good to see how all the sensors are reading and what the ECU is actually doing on the log when the problem happens.

The injector voltage going 0 momentarily in F11 is normal, and this is the time when the injector is actually firing. You won't be seeing it always go zero though because it happens too fast the ECU won't be able to measure it every time. 1 and 3 are the primary outputs by the way. You didn't see 2 and 4 doing it at that time probably because the secondaries aren't firing yet.

Thanks.
Mark