Hi all

 

newby here, I’m hoping you can help before I tear out what little hair I have left lol

 

2005 Focus 1.6 Zetec. Bought as a winter hack, so don’t want to spend much on it.  Started running on 3 cylinders the other day.  I wasn’t far from home, so it was only driven around 3 miles like that.  OBD reader said misfire cylinder 4 P0304.  Replaced the coil pack ( non original) and plugs, problem still there.  Tried swapping leads,  made no difference. Cleared the code, it then came back along with P0270 Cylinder 4 Injector Circuit Low.  Have replaced injector 4 with a known good one, problem still there.  When I changed the plugs, number 4 was soaking in fuel, which made me think that perhaps the injector was stuck open, which is why I changed it.

 

Have sprayed the electrical plug going on to the coil with contact cleaner in the vain hope that it was something as simple as that, but no such luck...

 

Am I right in thinking that P0270 points to an electrical problem? I’m almost at the stage of using my AA homestart to see what they can find lol

 

any advice appreciated, thanks 😊👍

 

 

Not sure how the focus injectors work but some have a constant voltage and the ecu controls the ground side. So perhaps you have a constant ground/short on the wiring to injector 4? 

14 hours ago, stef123 said:

Not sure how the focus injectors work but some have a constant voltage and the ecu controls the ground side. So perhaps you have a constant ground/short on the wiring to injector 4? 

Thanks Stefan. I’ll have a look into that.  Electrics aren’t my strong point, but I’ll see what I can find lol

when mine had a moment on Tuesday…. (plug leads and coil replaced - all normal now) one post suggested in rare cases it can be the injector....    and went on to say, it ends up blowing the brains out on the output for that injector in the PCM

1 hour ago, Botus said:

when mine had a moment on Tuesday…. (plug leads and coil replaced - all normal now) one post suggested in rare cases it can be the injector....    and went on to say, it ends up blowing the brains out on the output for that injector in the PCM

Yeah, I’ve read that too. If that’s the case, it’s heading to the scrappy lol

Sorry, meant to come back and update, but completely forgot.

 

turned out the plug lead was dead for number 4. The one I’d used to swap out to test was apparently goosed as well.  Got a new set, stuck them on, job sorted.  Thankfully nothing more serious. Thanks for the advice 👍