Dreaded p0300

[agon3279]

Well guys here I am with a horrible running vehicle. It all started last night. I was on my way home when all the sudden the check engine light started to blink. So I pulled over reset the battery and well, that didn't work. So this morning I brought it over to autozone an had the code pulled. Yep. It was P0300. So I bought ac delco plugs and a brand new coil pack. Put all the new plugs in and then I started one by one to test the coil packs. Sure enough it was cylinder one. Changed the pack and that did nothing. I check all coil packs and they are all getting spark and firing. I cleaned the throttle body also. So here I am, completely stumped and I don't know what to do. By the way, it is burning oil like crazy since it is now misfiring. I appreciate the help and feedback!

Oh yea. Buick Rainier with I6 and 95K miles. Oil change just done on Wednesday.

 

[IllogicTC]

Well guys here I am with a horrible running vehicle. It all started last night. I was on my way home when all the sudden the check engine light started to blink. So I pulled over reset the battery and well, that didn't work. So this morning I brought it over to autozone an had the code pulled. Yep. It was P0300. So I bought ac delco plugs and a brand new coil pack. Put all the new plugs in and then I started one by one to test the coil packs. Sure enough it was cylinder one. Changed the pack and that did nothing. I check all coil packs and they are all getting spark and firing. I cleaned the throttle body also. So here I am, completely stumped and I don't know what to do. By the way, it is burning oil like crazy since it is now misfiring. I appreciate the help and feedback!

Oh yea. Buick Rainier with I6 and 95K miles. Oil change just done on Wednesday.

You covered the air and spark part of the equation, but how about fuel? Have you examined the fuel injector(s)? I myself don't know enough on the subject to get specific on what needs to be tested, but I do understand fire, and you may not have fuel, or have severely reduced amounts of fuel, running to cylinder one.

 

[CaptainXL]

Burning oil "like crazy" doesn't sound good. Time for a leakdown test. I would consider this priority one. Don't drive the vehicle.

 

[Blckshdw]

When you pulled the plugs, did you have any oil in the spark plug wells, or oil in the spark plug threads? If so, you may need to retorque your valve cover bolts.

 

[IllogicTC]

When you pulled the plugs, did you have any oil in the spark plug wells, or oil in the spark plug threads? If so, you may need to retorque your valve cover bolts.

When checking the valve cover bolts, the torque is 89 INCH-POUNDS. NOT foot-pounds!!!! Yes, it seems rather loose (it actually translates to 7.41667 foot pounds) but that's all it takes. To get a measurement this precise you'd probably need one of those tiny 1/4" socket torque wrenches.

 

[CaptainXL]

When you pulled the plugs, did you have any oil in the spark plug wells, or oil in the spark plug threads? If so, you may need to retorque your valve cover bolts.

I have read and agree that oil seen on the spark plug threads is from the oil falling past the plug tapered seat running down the threads when the plug is removed.

Oil doesn't actually get past the plug and enter the cylinder. If it did then there would be no oil in the spark plug well. It would all be sucked dry from the downstroke of the piston.

No, it sounds like he has a much bigger problem. Especially if he is burning oil "like crazy" which sounds excessive.

 

[agon3279]

When I took the plugs out there was oil in the hole. But plug 1 was pretty bad. There was oil on the threads and it looked pretty fouled and burned. And when I was testing the spark with the engine running thats when it was burning oil. The water left on the blacktop from the exhaust had oil residue and when I pressed the gas a little, a lot of white smoke came out and it had the smell of burning oil. I'm pretty familiar on how the oil smells when its burnt. I used to have a town car and they are notorious for the valve seats wearing away causing the engine to burn oil. That's kind of what i'm leaning towards. Either a valve seat has worn away or an exhaust valve is burnt.

 

[agon3279]

[video=youtube;KuMqVx40c-g]http://www.youtube.com/watch?v=KuMqVx40c-g&feature=youtu.be[/video]

 

[CaptainXL]

Yes, if it burns oil shortly after starting then that usually means valve seals.

But if you need proof that it is not the valve cover leak then clean out the spark plug well and stuff something like bath tissue to soak up any oil. Let it sit overnight, remove the tissue, replace coil and start. Still get white smoke? If yes then it is the valve seal. You could also apply some ant seize on the plug threads which would block any oil (if it somehow made it past the spark plug seat...which I have doubts)

 

[agon3279]

Here is an update. So I took the vehicle to a shop for an inspection. Good news is that all injectors are working correctly and all coil packs are good. Bad news is that cylinder 1 has ZERO compression So at this point the total to get it fixed is going to be $2500. Does that seem around the norm for a head teardown/rebuild?

 

[Texan]

I have watched your video three times, and I think you should get a second opinion.

 

[CaptainXL]

Here is an update. So I took the vehicle to a shop for an inspection. Good news is that all injectors are working correctly and all coil packs are good. Bad news is that cylinder 1 has ZERO compression So at this point the total to get it fixed is going to be $2500. Does that seem around the norm for a head teardown/rebuild?

Pardon me but that is bull crap. The shop should be doing a leak down test and giving you an accurate diagnosis. Not just hooking up a compression tester and only telling you it has zero compression. Of course it very well may, but due to what? Valves, rings? The shop needs to be specific and have everything in writing.

And you definitely need a second and a third opinion before spending that kind of dough.

 

[IllogicTC]

Are you on a PC? If so, grab the TSB pack I posted, located here. (mega.co.nz, just download the whole folder if you want).

You may want to have a look at the following TSBs:
PIP4138N - SES Light, Misfire, DTC P0300, And/or a Chirp, Squeak, Squeal or Tick Noise - Potential Valvetrain Concern
PIP4013C - In-Line Truck Engine Misfire At Idle
PIP3472A - In-Line Truck Engine Misfires On End Cylinders
03-06-04-030H - Various Driveability Symptoms Due to Clogged Fuel Injectors
02-06-05-004B - Misfire DTCs, P1380, P1381, and Catalytic Converter Damage Due to Installation of Alarm Systems (Only applies if you have an aftermarket alarm installed)

The first two I listed involve cylinder testing. The first says a compression test is acceptable, but BOTH mention leakdown tests. I'd have a leakdown done myself. I agree very much with Captain that a second opinion at BARE minimum is required for fixes running $1000-1500 and above. $2500 is a down payment on a new car, just to HOPE it's the issue. And it could be, but $2500 could be an overkill fix for something that may be $500, you never know.

 

[NJTB]

Well, for me if I'm faced with an expensive repair I'll try to do all the cheap fixes first.
You stated in your post this engine misfire happened suddenly, which leads me to believe it was sudden and catastrophic. You could have a hole in the piston, burnt valve, bent valve, etc. The leak down test will confirm it. If you have a camera to put down the hole, you will be able to see the pistons, valves to confirm it. If it is a burnt valve or piston, the engine has to come apart, nothing else you can do.
The fact that the spark plug came out sooty and black isn't good. Could mean the problem was getting progressively worse, and when it got bad enough, the CEL turned on.
I'm going with the 'sudden' scenario, and think a piece of carbon broke off and is holding a valve partially open, so here's my suggestion.
Remove the plug, bring the piston up to TDC, and fill the cylinder up with Sea Foam, GM Top Engine Cleaner, or the like, and let it sit for a while. If it is a piece of carbon, this will soften it.
With the plug still out, crank the engine (rag over the hole) until the cleaner is all gone. It's gonna be messy. Make sure all the liquid is out of the cylinder, put it all back together and try it.
If it fixes the problem, great. If it don't, you tried.