Please help me fix the 3rd engine this car has had. It’s misfiring and knocking and I cannot diagnose them.

[Joseph Morgan]

Hi, I have a series 2VY executive police pack which I bought with a cracked head with plants to fix it only to find out that once I did fix it. The engine was knocking quite bad which I think was pistons slap as I could wiggle the piston inside the side in the engine with just my hands, anyway, bought another engine. That one was cactus misfired like crazy struggle to start, and then it locked up, returned. It got another engine both of these from the same wreckers yard. This engine that currently is in, it has been fully rebuilt was working fine for a little bit with the misfire slight misfire not too bad, then it started developing and tick and now a knock that will not go and misfiring worse than ever now. The used to go away after you drove the car hard and it would get nice and warm. The knock would actually disappear but now it’s there all the time it’s not too loud. To be honest it’s not as loud as the original engine that had piston slap or rod knock but it’s there all the time now and it’s misfiring quite badly. Can anyone please help me try and diagnose both issues as I am sick of this and just do not have the money to keep fixing things.

 

[vc commodore]

I'd be starting with what common parts were used inbetween all engines and replace those first....

 

[Joseph Morgan]

I'd be starting with what common parts were used inbetween all engines and replace those first....

Yeah I had a lot of people on Facebook say it could be the flex plate which I have shared over the two engines because the one on the engine that came with it was actually slightly damaged. Not sure it’s that though because I did run the engine without it connected to the trans, so I didn’t have any load on it and still made that noise. Also, I believe there’s a massive vacuum coming from the PCV valve and also there’s a lot of oil in the intake pipe.

 

[Immortality]

Make sure the PCV valve is in there as well as the plastic piece that goes under it.

I wonder if you have a bad injector and causing a cylinder issue that is then eating the bearings. Lots of knock will kill bearings.

A bad or dirty MAF can also cause a lean condition and that may cause engine issues long term.

 

[Joseph Morgan]

I took out the PCV valve and cleaned it, and there was something underneath, but like only looked at it through borescope because I didn’t fully take the intake off. But yeah, the valve certainly there. I replaced all the injectors fuel rail and fuel filter with one from another engine and nothing changed at all, and when I unplug each injector while it’s running, the car gets worse showing it’s not really a fuel problem.