07 escalade p0300 and stabilitrac light on running rough

[rcsnipe2000]

hey all, long time lurker, 1st time posting

i have a 07 escalade with a 6.2. i have a hard miss on #6. (used tech 2 for pulling the code) p0300

i have swapped 2 injectors to see if it went to the new hole. no luck

i have good spark at the plug (use a spark tester at the plug and coil wire) good spark

i have sprayed brake clean around the intake and no leaks found there.

i have good fuel pressure. 58ish on the fuel pressure gauge

i dove this car around yesterday with no probs. even topped off the tank. this morning, this happens.

any ideas? anyone ever have this happen just out of the blue?

thanks for any help,
rc

 

[89Suburban]

How many miles on it? Did you pull the actual spark plug to inspect?

 

[rcsnipe2000]

hi, 210k on it. pulled the plug and it was clean. no fuel on it at all.

rc

 

[89Suburban]

hi, 210k on it. pulled the plug and it was clean. no fuel on it at all.

rc

Time for a compression test or knock off the valve cover and check the rockers on that cylinder. No funny noises? Hopefully others will chime in here.

 

[rcsnipe2000]

yes, thats what the plan is for tommarra. see what the compression is. as far as valve noise, i dont really hear anything suspect.

rc

 

[89Suburban]

yes, thats what the plan is for tommarra. see what the compression is. as far as valve noise, i dont really hear anything suspect.

rc

Good luck hoss.

 

[Joseph Garcia]

Keep us updated, and we'll help out where we can.

 

[rcsnipe2000]

ok fellas,

again, my prob is a hard miss fire on #6.

so, today i pulled the valve cover and all the lifters and rockers are working with no play in them. so no stuck lifter for sure.

i did a compression test on #6 and it is at 160. so pleanty of compression there.

i did look through the spark plug hole while i had the plug out with a snap on video borascope. i could see a bit of a carbon ring around the top of the cyclender and some carbon build up on the top of the piston. nothing that screams we have a problem, but enough to go ahead and do a de carbon on the engine. so i put a can in and im letting it sit over night for a good soak.

anything yall can think of to check, please let me know.

 

[Geotrash]

ok fellas,

again, my prob is a hard miss fire on #6.

so, today i pulled the valve cover and all the lifters and rockers are working with no play in them. so no stuck lifter for sure.

i did a compression test on #6 and it is at 160. so pleanty of compression there.

i did look through the spark plug hole while i had the plug out with a snap on video borascope. i could see a bit of a carbon ring around the top of the cyclender and some carbon build up on the top of the piston. nothing that screams we have a problem, but enough to go ahead and do a de carbon on the engine. so i put a can in and im letting it sit over night for a good soak.

anything yall can think of to check, please let me know.

I would try swapping coils and plug wires also and see if the problem follows. I've seen coils produce a spark at starter speeds but fail to deliver reliably at engine speeds. I've also had an injector connector come loose and produce a misfire. Hit it with electrical contact cleaner and reseat it firmly to be sure.

 

[rcsnipe2000]

yes, i forgot to mention i did swap the coil and plug wire to #2 and the injector with #4. i still have a #6 miss fire. nothing moved to another cylender after the swap. it stayed the same

 

[rcsnipe2000]

so, i dropped it off at a shop yesterday afternoon. i got a call this morning about 9 saying. it has 0 compression on #6

i have a hard time believing i am getting 160 psi on #6 and they are getting 0psi. so i picked it up. i personally dont think they even did the test.

 

[rcsnipe2000]

ok, so today i did another compression test to find it at 0!!!

so back off with the valve cover and sure enough! a broken spring on a ex. valve #6!

so im off to find a valve spring!!

any chance the valve is bent? anyone been here?

i took another look with a bora scope and best i can see there was no contact unless its in a area i couldnt see.

 

[89Suburban]

ok, so today i did another compression test to find it at 0!!!

so back off with the valve cover and sure enough! a broken spring on a ex. valve #6!

so im off to find a valve spring!!

any chance the valve is bent? anyone been here?

i took another look with a bora scope and best i can see there was no contact unless its in a area i couldnt see.

@iamdub

 

[rcsnipe2000]

replaced the valve spring and all is good again!

thanks fellas!

 

[89Suburban]

replaced the valve spring and all is good again!

thanks fellas!

Awesome sauce!!!

 

[Geotrash]

You dodged a bullet! Well done!

 

[donjetman]

replaced the valve spring and all is good again!

thanks fellas!

It may be time for all new valve springs?

 

[Geotrash]

It may be time for all new valve springs?

+1 to this. There are lots of examples of 2007 6.2 L braking valve springs. It would be wise to replace them all in my opinion.

 

[Rocket Man]

It may be time for all new valve springs?

Exactly. I believe there’s a known issue with the springs on that engine as @Geotrash mentioned. If one broke and you got lucky, I wouldn’t just count my blessings because if another breaks your luck will probably run out. That can do a lot of damage quick.

 

[donjetman]

I guess should change mine too then? 182k miles and climbing on our L92.