Misfire......from PCV?
 

Long story short bought the car 33k miles intake tube nipple was broke off from PCV line. Ordered new PCV tube and during the week of waiting for it to show up the car would misfire horribly and CEL came on P0300 and P0303. This was only during WOT that it would happen. I changes plugs to stock ACDelco 41108 plugs gapped at .032. Misfire seem to go away, but oh no spoke to soon same issue. Then finally the new PCV tube came in and I replaced it today. The car has not misfired yet Ive done a few WOT pulls through 1-3 gear. I have an appointment with the Stealership for Monday at 9am.

Can the PCV tube cause the car to misfire if left unhooked?

Car is stock with GMS1

Yeah, it was messing with the air/fuel ratio probably, therefore causing mifires.
Honestly, im trying to think of something that doesnt make these stupid cars misfire and run bad...lol
Glad its running better, wish mine was...

Well I drove the car more and the misfire is still there......FML

I have an appointment with the dealership tomorrow at 9am so they can look at it the CEL is on still.

With the info from search's Ive gathered seems to me that there can be these problems left:

-Bad injector or seal
-Dirty Valves

I have seen some people talk about cracked piston rings and what not so I will find out tomorrow i guess.

I just spent a day with a car with PCV issues, but not like that.
The PCV nipple that broke off on your car is the fresh air inlet , and as its metered air taken off the inlet tube between the maf and the turbo inlet, it does not help the car to have a massive air leak there.

BUT that said, I strongly suspect your inlet valves are coked. The PCV valve on this car that is in the inlet manifold was 100% NOT WORKING and the inlet ports were so coked its amazing the car ran.

Attachment 26294

this is the valve removed from the IM and you can see the residue that was washing the inside of the inlet manifold with oil. UGH.

Attachment 26295

DOUBLE UGH. Its a wonder it ran at all

Attachment 26296

it takes a while to upload to photobucket so I will post up the cleaned valves later.

Your car I beleive, needs either the head pulled and valves stripped and cleaned, or this a walnut shell media blast, There is still some scraping required to avoid endless media blasting, but I use a modified blast gun and its very easy to get in and around the valves. You can borescope in through the vacuum fitting port if you want confirmation; borescopes can be had on ebay for 20 dollars or so.

I was surprised the PCV valve was not working they are pretty robust, but I would suggest that the options for you are clear. One thing I caution you about, that if the blow by is significant and its a used car, look for evidence of a previous tune, and expect the piston rings and /or the ring lands to be broken. Ihope not, Good luck.

I seafoamed my car and replaced the plugs with factory ac delco gapped at .30 and it seems to be idling better. My car instantly started smoking when i started doing the seafoam, and continued to get real bad until i finished, so im sure im in need of a walnut blast too:(

How many miles on that car John? Those valves seem quite a bit worse than mine were. I also wish I would have replaced my PCV valve in the manifold when I had it off.

Seafoam wont touch this crap. Walnut blast is needed.

Attachment 26286

I cover the entire front of the car, duct tape the head, and use towels around it as the towels trap the blast residue and stop it from creeping every where. Its sort of like being a dentist lol.

The customers fuel mileage has almost doubled...


Attachment 26287 almost done. The valve cleans up easier than the port, to tell the truth. The back side of the valve is difficult but the modified gun I use takes care of that pretty much.

Attachment 26288

taking pictures of this and getting on with work makes it a pita, and my camera and me dont do a great job . Next time I will just use a borescope camera directly to the PC .

Attachment 26289

One vacuum nozzle I have goes right in the port; I use a wide blade one above the port when blasting. Most of the media comes out and up not down. If you do this yourself, dont forget to get goggle safety classes, some ear protection and the most important of all, a simple respirator. I have a relatively small 220 v compressor that does 12 cfm at 90 psi and the gun handles it no problem
Attachment 26290


Okay you can go home now....lol

Lol @ seafoam. I may try building a distribution nozzle to spray in the individual runners through the vcacuum port and shoot it in and let it sit. But you would have to do it with three cylinders and wait, and then the other cylinder after. I dont know how long you would have to wait for it to emusify that crap its hard, its sticky , its grungy. Ugh.

The owner purchased it at 65,000 kilometers and it has about 139,000 on it now. I was shocked that the pcv valve wasnt working at all, I have not encountered that at all, but the valves were a mess no doubt and the port was half normal size lol. Hard to suck through a straw to make combustion.

The owner takes care of his car; ( Not my choice in some things: he has such a dark tint I cant stand driving the car I have to open the side windows just to use the side view mirrors, and the aftermarket inlet is not my choice, you folks know I prefer a stock inlet box and filter.

But it comes down to fuel ( he uses 94 only so thats good) Oil, ( he uses castrol edge and I would not) and driving cycle. I am afraid that driving cycle has a lot to do with it. Why did the PCV valve fail? I have no clue. That one puzzles me. And gives myself a big pat on the back for automatically changing them whenever I do an IM service, LSJ or LNF.

Well I checked CEL codes are P0303 and P0300 last time it was same codes. I did some data logging not sure if that would help identify the problem as I don't know how to understand the log.

buy a 20 dollar 7 led borescope plug it into yourlap top stick the probe through the brake booster port and see for yourself.

Just got the call from the dealership they say its #3 fuel injector and its covered under powertrain warranty they are replacing it now.

UGH! My car is at 60k miles now, I may gonna have to check this out. I am surprised my car runs smoothly.

My car has 62k, and i am very anal with it, but yet i didnt see mine becoming ths way.
A good sea-foam treatment does moderately help in my opinion though. I think if done often after 30k miles, then the major gunk will never happen, or wont be near as bad.
Just an opinion though.

the sad thing is ^^^ hoping wont make it so. Thats why I worked on a PCV upgrade solution. There is just so much blow by going on. It gets worse with tunes, much worse, and also sad to say, piston ring lands can fail/ or piston rings, and it just makes the condition worse.

The issues with DI motors are industry wide, and the auto makers are reacting, but not with retrofits.

In the case of Toyota and Saabm in the early 2000's with NON DI engines, they had PCV issues with sludging and had to come up with solution, governmint enforced.

Not happening here.


Audi BMW, Toyota all do the media blast deal. I am totally unconvinced that seafoam does anything much, but please spend 25 dollars on a borescore and have a look at your valves and post on up. It would be great if you have clean valves!!

Alright brotha, you are right.

How much for PCV upgrade ? PM Me

done thank you

Got my car back today.....no misfires .....i also talked to the service advisor about checking the vavles when they had the intake manifold off and he allowed me to go back and look and they were clean. Gave me some piece of mind for a while at least.