Broken Intake Valve from Valve Float 6.2L L92?

[kbuskill]

So i swapped the injecrors, cleared the codes and fired it up....still cylinder 8 misfire. So im guessing its a lifter or maybe head is cracked?

Have you swapped coil packs to see if the problem moves... could also be the connector/plug for the coil pack.

 

[gpracer1]

Time to do a compression test dry, record value.
Squirt oil in spark plug hole and repeat, record value.

 

[Lsnoob13]

I checked the coil when i put in new wires and plugs. Id have the truck on and pull the wire and it shot out a good inch of spark so i figured it was good. Wires are new and i swapped it after i put it in to make sure it wasnt the wire and same thing happened. Ill do compression test next. When you say squirt, would like about half a syringe be good? Like medicine syringe? Im guessing if value with dry and with oil differs it means rings?

 

[gpracer1]

I checked the coil when i put in new wires and plugs. Id have the truck on and pull the wire and it shot out a good inch of spark so i figured it was good. Wires are new and i swapped it after i put it in to make sure it wasnt the wire and same thing happened. Ill do compression test next. When you say squirt, would like about half a syringe be good? Like medicine syringe? Im guessing if value with dry and with oil differs it means rings?

Yes, if it stays the same after adding oil it’s the valves or a hole in the piston, if it is higher then the rings.

 

[Lsnoob13]

Ok so i got time to do the compression test....not to good. I did a control test on cylinder 4, which is 2 cylinders forward of 8. On 4 i got around 190ish PSI ill post pictures in a bit. On 8 i got 90PSI, i syphoned a bit of oli into the cylinder and got 90PSI again. So at this point i know its not the piston or rings. I ended up removing the wheel and splash guard to get to cylinder 8, made it tons easier to get to then last time i worked on it. As i was down there i noticed alot of oil on the block and heads.....i hadent noticed it before. So i know there is a head gasket leak and maybe a valve cover gasket leak as well....but would that cause this entire feasco?

 

[Lsnoob13]

First picture is spark plug out of cylinder 4. Has a strong fuel smell and something i didnt notice last time i changed the plugs.....a bit of oil. Second picture is plug out of cylinder 8. Looks fairly the same but less soot on the plug.

 

[Lsnoob13]

Here is the picture of the oil on the block i noticed. Possible head gasket and valve cover gasket leaks maybe?

 

[gpracer1]

Well 90 psi, that sucks.

You can put the piston at top dead center and hook an air hose to the compression tester......minus the gauge part, and force air into the cylinder.

Listen for the air flow out the exhaust valve/tailpipe or intake manifold.
If its head gasket or piston, check crank case airflow out the oil fill cap, cap removed, and or radiator building pressure.
I would do a compression check on all cylinders at this point and write them down.

 

[Lsnoob13]

Piston in cylinder 8 looks ok from what i can see. Its not much but im not sure. I moved it around and looked as best as i could recording and doing that was kind of hard but i think i got a decent shot of the piston. Looks like alot of build up but looks in tack i think. Im going to have to do a head gasket replacrment so ill look at it better there. While i was in there i wanted to see what gaskets were better that stock. If i ever got it running down the road id like to maybe put in a cam, long tubes and tune maybe a few other things. What do you guys recomend i "upgrade" while im in there to increase my "reliability" i was thinking head studs maybe and things like that simple things id have acces to while the heads were off.

 

[swathdiver]

Piston in cylinder 8 looks ok from what i can see. Its not much but im not sure. I moved it around and looked as best as i could recording and doing that was kind of hard but i think i got a decent shot of the piston. Looks like alot of build up but looks in tack i think. Im going to have to do a head gasket replacrment so ill look at it better there. While i was in there i wanted to see what gaskets were better that stock. If i ever got it running down the road id like to maybe put in a cam, long tubes and tune maybe a few other things. What do you guys recomend i "upgrade" while im in there to increase my "reliability" i was thinking head studs maybe and things like that simple things id have acces to while the heads were off.

@randeez