Dead plugs tell tales?

[Four0Sport]

The 4.0L in my 93 Sport has been out of action for a while, i havnt bothered with it bc ive been driving my 97 5.0L around. On my 1 day off this week i decided to fool around with the 4.0L. It starts fine, runs barely, acts like its running on 3 cylinders.. so i pulled the plugs. Bare with me bc i forget the cylinder firing order.. back right plug's electrode was fused to the ground, right middle plug electrode was non existant, right front plug was fine.. just fouled. Left rear plug fused, left middle missing part of the electrode, left front fine.. not even fouled. I was hoping my problem was a plugged cat, or even a burnt valve in one of the heads but now I dont know what to think. if anyone has any suggestions from the condion of the plugs i would appreciate it. Tried to get a picture to upload but it is currently lost in transit between my camera and my pc.

 

[FROADER]

Mine looked like that at one time except all of my electrodes were completely gone. I'm not sure how it still ran. My #2 cyl. ended up being dead. Good luck with it.

I was trying to find my picture, but I can't right now.

 

[mikeinri]

I think we need a little more info. How many miles on the motor? Was the truck acting this way before you parked it to drive the newer one? How many miles has it been since the plugs were last replaced before this problem started? Have you gotten any CELs and/or checked for codes?

If it were me, I'd start with throwing new wires and plugs in there and drive it for a while to see if the problem comes back. If the problem doesn't come back, drive it for a while (an oil change worth of miles), pull the plugs and see how they look.

That's a pretty cheap fix, and you may get lucky and it might solve the whole problem. If nothing else, you need new plugs at this point anyway.

Mike

 

[Four0Sport]

i was driving to work on the interstate climbing a hill and heard a pop and lost power.. the truck actually shut off, i had to put in in nuetral and restart it while on the interstate. pull in to work the motor is shakin and gas is dripping out of the tail pipe. the plugs and wires were both fairly new.. 2-3 months?. I changed all six plugs, it runs smoother but there is still a shake in the motor, maybe a dead cylinder or 6? lol

 

[Mud Bug 94]

the non existant electrode if from them getting to hot...not the motor just the plugs.

 

[Maniak]

Pinging/detonation can also destroy the electode.

~Mark

 

[mikeinri]

Did you get any codes?

Either way, I would re-replace the plugs at least so you can hook up a reader and do the balance test (tells you which cylinders are bad). I'm making a huge assumption that you are using "good" plugs. There are lots of threads here about which brands seem to work better than others.

Mike

 

[Four0Sport]

I've been having good luck with autolite platinums.. and theyre cheaper than the factory motorcraft which is made by autolite (or so ive been told). reader? balance test? I tried pulling a code but to no luck. my friend matt said if i would of used ac delco plugs none of this would have happened, typical chevy guy. could a plugged cat cause the plugs to get hot enough to blow? there was a small amount of detonation while under a heavy load on the interstate but nothing bad. the truck ran fine the 60K miles ive had it. thanks for the help guys.

 

[mikeinri]

The reader and balance test I am referring to involve connecting a code reader (used for checking CEL codes) and running a series of tests.

The manual that comes with the code reader should explain this. Also, do a search on this forum for KOER code checking.

Mike

 

[Four0Sport]

i was familiar with the KEOR test doing a cylinder recognition test but didnt know it involved a cylinder balancing test. oh well.

 

[mikeinri]

I think we may be talking about the same thing. What I am calling the "balance" test is the one that reports if the computer thinks a cylinder is bad.

Mike

 

[quicklook2]

what did the problem turn out to be?

what was the fix.