Ron_Stoppable

iTrader: (1)

Did a 5.3 swap on my 2000 S10. Motor is an 05 5.3. I havent been able to pull codes since the engine is back out of the truck because of major frame damage. But I suspected that cylinder 1 & 2 werent firing because of how the header tubes looked and felt. The exhaust ports on the heads also have minimal carbon in those 2 cylinders vs the others. The plugs on both of these cylinders are alot darker. The first pic shows from LEFT to RIGHT cylinders 2,4,6,& 8.


And this pic is cylinders 1,3,5,7 from left to right

Old Geezer

iTrader: (3)

Junkyard engine?
If so, could be the injs are fubar'd.

usdmholden

I looks like those plugs weren't firing, as you suspected.

SS10Tech

How long have you ran these plugs?

6, 8, 3, 5, and 7 all show carbon deposits to me, but nothing on the electrodes which is odd. Possibly means you did not run them for very long before the bent frame. Carbon simply means the AFR is too rich. The pure white insulators and lack of carbon buildup on them could mean you also need to consider a different heat range if these plugs had some life on them.

GMtechmatt

they smell like fuel?

Italianjoe1

I'd check for spark on those two cyl's first. Could be bad coils/wires but that's odd to find two adjacent ones failed at the same time. Possible blown head gasket issue causing very low compression on them, but usually you will still see them firing a little. Those appear to be getting no spark at all.

Ron_Stoppable

iTrader: (1)

I did a bit of research and actually heard that Anti-sieze could cause this. My plugs did have anti-sieze near the tip now that I think about it.

usdmholden

I have had anti seize short out plugs before.

If this is the case, clean them up pretty well and they will be ok.