Replacement motor questions but hopefully fixable

[drdave81]

Reading into this a bit, what made you think you had spun bearings, and then went to a misfire? Is there a knocking sound?

Not to sound rude, but you seem to be all over the place with this. Spun bearings, ignition issue, fuel issue..............
Before you go throwing parts at it, do you have any kind of a scan tool?
Let's start with some good diagnosis and go from there. It'll save you money. You have a P0304, misfire on cylinder 4. You can take a plug wire from say cylinder 5 and swap them. It's the easiest thing to start with. See if the misfire moves. If not, go to the coil, swap them. If not, swap the spark plug. These are all easy, free tests.

 

[rockdogz]

Reading into this a bit, what made you think you had spun bearings, and then went to a misfire? Is there a knocking sound?

Not to sound rude, but you seem to be all over the place with this. Spun bearings, ignition issue, fuel issue..............
Before you go throwing parts at it, do you have any kind of a scan tool?
Let's start with some good diagnosis and go from there. It'll save you money. You have a P0304, misfire on cylinder 4. You can take a plug wire from say cylinder 5 and swap them. It's the easiest thing to start with. See if the misfire moves. If not, go to the coil, swap them. If not, swap the spark plug. These are all easy, free tests.

It sounded like a knock at first so I assumed the worst. After getting it back home and hooking up the scan tool, I pulled the P0304 and started researching it. I pulled the plug on 4 and while trying to get the wire off it pulled apart.
While I’m waiting for new wires to arrive I’m going to do a compression check to rule out a bad valve or lifter.
As far as the VLOM, I had already been experiencing some oil leaking from somewhere higher on the block and I was going to replace the valve cover gaskets. I also have some small amount of coolant leaking somewhere although I don’t see it on the ground. I just need to add more to the reservoir monthly when it gets low. When I read about the VLOM issues of oil/coolant leaking I have a feeling it could be related.

 

[rockdogz]

Compression checked out ok. Tried new plug wire and spark plug, and swapped coils with cylinder 2 - the misfire stayed on cylinder 4. I suppose it could still be a lifter right? The compression test wouldn't rule that out because it would fail collapsed right?

 

[Rocket Man]

Compression checked out ok. Tried new plug wire and spark plug, and swapped coils with cylinder 2 - the misfire stayed on cylinder 4. I suppose it could still be a lifter right? The compression test wouldn't rule that out because it would fail collapsed right?

Injector harness?

 

[Fless]

Or swap injectors with another cylinder.

 

[Rocket Man]

Or swap injectors with another cylinder.

Oh yeah, I missed the fact he didn’t swap injectors yet.

 

[TollKeeper]

While your down there swapping the injectors around, pull the valve cover off, and check for pushrod movement. This will also give you the oportunity to check for the lifter bridge being pulled from the head, or that the pushrod is even under the rocker. I have seen both, but usually on a high HP LS.

 

[rockdogz]

Ok thanks for the suggestions, I was going to pull the valve cover next but I will try swapping injectors first. Is there a way to test the injector harness?

 

[TollKeeper]

I think that requires a tech2 so you can fire each injector individually.

 

[Rocket Man]

Ok thanks for the suggestions, I was going to pull the valve cover next but I will try swapping injectors first. Is there a way to test the injector harness?

I'm not sure but I think you can swap from one side of the engine to the other.