Cylinder 2 - 4 misfire

[LSJuan.]

Hey everyone, I just recently bought a 2010 ve commodore (llt) for a first car. Bloke reckons it had a new engine put in about 5000ks ago.

I suspect that the previous motor has detonated and sent oil down the exhaust as it is caked and black.

Which has caused an engine light because the o2 sensors are f*cked

Car was running rough as guts and blowing smoke, revved the sh*t out of it and it blew the cats out of the exhaust and a heap of black smoke,
It then started to run way better.

Was driving today with a trailer down to Wollongong to pick up some parts for the car and the engine light started flashing. Car went into limp mode. Lucky I have an obd scanner, it threw o2 codes and low fuel rail pressure codes. Cleared it and continued on.

Car was fine and then absolutely sh*t itself. Was sputtering and blowing heaps of white smoke. Checked codes again and cylinder 2 and 4 were misfiring, car shut off. Cleared codes and tried again. Same thing… cleared codes again and revved it so it wouldn’t stall out. And the car just went back to normal after about 30 seconds, turned around and drove home, not a problem. Could the o2 sensors be doing this? Maybe a fuel filter or sh*t fuel? Even the fuel pump? Or is it a bigger issue?

Sorry for the whole book I just wrote, but thanks to anyone who might know.

 

[uglyoldfatbastard]

Bloke probably put in a second hand engine not a new one to be fair and that is why he probably sold it.
O2 sensors will throw codes if engine is misfiring so you need to get that fixed for a start before spending money on O2 sensors.
Low fuel rail pressure is an issue and the fuel filter is part of the pump in the tank HOWEVER low fuel rail pressure on a SIDI comes from the HPFP (high pressure fuel pump) which is on the rear of the engine on the passenger side. So it could be the pump in the tank not supplying enough to the HPFP or it could be the HPFP itself.
Going to take some diagnosing and checking and fixing each issue or you will be running around in circles.

Before anyone else mentions it go and get your battery load tested first that will please many people on here

Sorry no quick fixes for this one.

 

[LSJuan.]

Bloke probably put in a second hand engine not a new one to be fair and that is why he probably sold it.
O2 sensors will throw codes if engine is misfiring so you need to get that fixed for a start before spending money on O2 sensors.
Low fuel rail pressure is an issue and the fuel filter is part of the pump in the tank HOWEVER low fuel rail pressure on a SIDI comes from the HPFP (high pressure fuel pump) which is on the rear of the engine on the passenger side. So it could be the pump in the tank not supplying enough to the HPFP or it could be the HPFP itself.
Going to take some diagnosing and checking and fixing each issue or you will be running around in circles.

Before anyone else mentions it go and get your battery load tested first that will please many people on here

Sorry no quick fixes for this one.

Okay, thank you for that information.

I discovered yesterday that the battery ground terminal was loose to the point I just pulled it off with my hand. The car had been running like crap all day, I tightened it and cleared the codes and so far the car has been fine. Could that be another possible cause? Or is the car just coincidentally running okay for the time being.

I’m hoping that may be the case because if that was loose when I connected the trailer that could’ve been what caused the car to do all those random things.

Thanks again

 

[uglyoldfatbastard]

Okay, thank you for that information.

I discovered yesterday that the battery ground terminal was loose to the point I just pulled it off with my hand. The car had been running like crap all day, I tightened it and cleared the codes and so far the car has been fine. Could that be another possible cause? Or is the car just coincidentally running okay for the time being.

I’m hoping that may be the case because if that was loose when I connected the trailer that could’ve been what caused the car to do all those random things.

Thanks again

Bad ground causes all sorts of issues to these modern cars so maybe you will get lucky.
Battery terminals and charge is one of the first things I check when I get a car just a matter of habit so rarely catches me so maybe you should make it a habit as well and you never know it might save you a headache.