Dead Cylinder Analysis

[ronbo613]

Hello Everyone-I have become the owner of a 1995 4Runner. Unfortunately, the #1 cylinder is dead. The spark plug is badly fouled with oil and there is some oil blowby, so I am worried that I may have piston ring problems. It may be a bad valve or valve stem seal or even a bad head gasket, this is my first experience with a 3VZE engine, so I'd appreciate any first hand advice. I'll check the compression, but I think I know most of what I need to see here.
I've changed the plugs and wires, no difference. When I pull the plug wire and run the engine, it is the same with the plug wire on.
While this is my first 4Runner, it's not my first Toyota. I owned a HiLux back in the seventies, drove my FJ40 all over Baja on surf trips and I currently own a 1990 Toyota pickup with about 120K miles. None of these vehicles have ever been to a repair shop, I'd like to keep it that way.
Thanks in advance, any info or insight will be greatly appreciated.

 

[drmorbius]

Hello Everyone-I have become the owner of a 1995 4Runner. Unfortunately, the #1 cylinder is dead. The spark plug is badly fouled with oil and there is some oil blowby, so I am worried that I may have piston ring problems. It may be a bad valve or valve stem seal or even a bad head gasket, this is my first experience with a 3VZE engine, so I'd appreciate any first hand advice. I'll check the compression, but I think I know most of what I need to see here.
I've changed the plugs and wires, no difference. When I pull the plug wire and run the engine, it is the same with the plug wire on.
While this is my first 4Runner, it's not my first Toyota. I owned a HiLux back in the seventies, drove my FJ40 all over Baja on surf trips and I currently own a 1990 Toyota pickup with about 120K miles. None of these vehicles have ever been to a repair shop, I'd like to keep it that way.
Thanks in advance, any info or insight will be greatly appreciated.

It sounds like you may have an injector problem on that cylinder.

 

[ronbo613]

That is something I will check out before I rip the engine apart.
The heavily fouled plug really is what really is making me worry. When I took the plug out and saw the oil fouling, I was really bummed and made me think "worst case scenario".

Thanks for the advice.

 

[drmorbius]

That is something I will check out before I rip the engine apart.
The heavily fouled plug really is what really is making me worry. When I took the plug out and saw the oil fouling, I was really bummed and made me think "worst case scenario".

Thanks for the advice.

With a clean plug , a hot spark, and fuel coming from the injector it should still fire. It may burn oil at that point but it should run.

 

[ronbo613]

A compression check shows 140psi in the cylinder and the new plug looks a little dry, so piston or valve problems seem unlikely.
Good call on the bad injector, that looks like the problem.

 

[drmorbius]

A compression check shows 140psi in the cylinder and the new plug looks a little dry, so piston or valve problems seem unlikely.
Good call on the bad injector, that looks like the problem.

That's really good news for you! Glad it wasn't something more radical.

 

[ronbo613]

Yes indeed, I am stoked, to say the least. I just bought this 4Runner, it could use a little work, so not having to deal with a major mechanical issue is going to leave me some bucks to buff out the truck.
Thanks again for your help.