2f 3rd Cylinder not firing

[theRash]

So I convinced my brother to purchase an 87 FJ60. While doing the standard tune up I come to realize that Cylinder #3 isn't firing. My test for this was while the engine is running I pulled out each spark plugs and waiting for the engine RPMs to drop. My assumption is that if the rpms drop then the cylinder is firing. I took it out and there was no drop in RPMs. I tested that the spark plug wire is getting spark by getting electricuted.

My question is?.. Is this the best test? If its getting spark but no fuel to that specific cylinder.. how would I test that?

New spark plugs and wires. Haven't done the cap and rotor yet.

Any other thoughts on what might be causing this?

 

[Mace]

do a compression check

Adjust valves..

Any water in the oil?

 

[lynchmob]

damn, you got electrocuted. welcome back from the dead.

Do as mace said. Could be bad head gasket or a burnt valve.

 

[RredFJ40]

do a compression check

Adjust valves..

Any water in the oil?

Ditto - check number 4 also, I've blown the HG between 3 and 4, low compression on both but no water in the oil.

 

[theRash]

do a compression check

Adjust valves..

Any water in the oil?

Ditto - check number 4 also, I've blown the HG between 3 and 4, low compression on both but no water in the oil.

Thanks guys -

The PO mentioned something about the head gasket needed to be replaced due to a small leak. Funny thing is I did get a very little response from #4 when I checked it. We'll do compression and water in oil check in the few days. I have his old oil still from an oil change but I have enough work on my own to do. He can check his own oil. is the low compression and non firing cylinder(s) caused by a blown or small leaky HG?

 

[NocalFJ60]

is the low compression and non firing cylinder(s) caused by a blown or small leaky HG?

Most likely. The compression test will tell you a lot.

 

[Turd Ferguson]

Did you pull the spark plug out or the wire off? If you pull the plug the rpm's may not change much because not only are you killing the spark to that cylinder, you are relieving the compression off of it. Just a thought.