[SOLVED] Cylinder 1 Misfire - P0301 / P0300 Mystery

[Toothbrush]

Prior to the valve job - oil in abundance - fixed all leaks (mentioned in first post) - currently leak free. I've checked that so many times I have multiple mirrors, some with lights, and a camera now just to be sure. Have felt all the way around (except the very back side against the firewall) and nothing.

I've checked the first intake and exhaust springs/rocker/seals closest to the front with the camera through the oil fill and they look fine. Can't get the camera at a good angle to check the other two for cylinder 1.

As far as oil in the coil pack / spark plug tubes - dry as a bone. Spark plug does have oil build up on center and ground electrode (tip) not on the threads. I've tried the plug that was there to start with + new NGK and Bosch (no change).

I've swapped so many plugs / coils around I can do it sleeping now.

[AlphaBetaX5]

Did you replace intake seals?

Have you turned on the engine after you replaced intake seals?



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[AlphaBetaX5]

Btw, to test your vanos in ISTA, go to service functions-power train-Vanos
You can reset your vanos /and realign the angel there.


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[Toothbrush]

Originally Posted by AlphaBetaX5

Did you replace intake seals?

Have you turned on the engine after you replaced intake seals?

New seals are on the intake, but I haven't got to the point of installation yet, so yes to the first question and no to the second.

Going to see if I can pick up some injector o rings tomorrow and replace those while it's super easy to get to them. Then reinstall everything, fill up with new coolant/bleed the system, then see what happens...

[Skyline]

Oil on a spark plug can only come from one of two places; from the valve seal, or a bad ring.

Did you ever do the compression test that was suggested early in this thread? I wouldn't throw any more effort at this engine until you're sure you don't have a bad ring.

Assuming the compression is OK, you might consider a chemical decarbonization. There are devices that hook directly to your fuel rail to spray a chemical solution into your engine. Basically, you shut down the fuel pump, so the engine runs for about a half hour on strait solution, at a set pressure. There are two different types of solutions; one that is designed to decarbonize, the other is an injector cleaner. This is the rig you need:

https://www.amazon.com/OTC-Tools-764...70_&dpSrc=srch

This listing is the basic kit, and comes with a few adapters. They make a "Pro" kit that comes with a whole toolbox full of adapters at a higher price level:

https://www.tooltopia.com/otc-tools-...tid=OTC6550PRO

That last link also has some videos.

I bought one of these kits to clean out the engine on my G35, which DID have bad rings, and was burning a quart of oil every 500 miles. Worked pretty well, car ran a bit better. (Those V6 Nissan engines are really crap, and when the car needed a third engine at 150k miles, I sold it.)

[Toothbrush]

Compression test is on the to-do list this weekend. When I have some extra time, I'll probably be pulling the valve cover off to take a look, unless some miracle happens.

Intake is back on and the coolant leak appears to have been fixed with the new valley pan. This seems to have taken care of a lot of the rough idle and the P0300. Carly and OBD Fusion tell me the same thing, but I need to reinstall ISTA (changed laptops recently).

I'll look into the decarbon links - thanks!

[Orthotist]

Does it have an individual throttle body? If It does, you will need two people. One to punch the gas and another to make sure the rod opens the plate. Just repaired M3 with an all else failed tactic as you are facing. Mine was a P0306 code due to this. Youtube: DIY_NATION_TH

[Toothbrush]

Another update: Finally got around to trying my hand at a compression (wot - two people) test on Bank 1, couldn't get the gauge to hold the psi so thinking the tester has a leak somewhere - will look into that and/or get a different gauge and do a complete retest of bank 1 - but till then...

Cylinder 1 would only go up to 30 psi. Cylinders 2, 3, and 4 120+ (couldn't quite tell since I couldn't get the needle to 'stick'.

Put about 3/4ish table spoon of oil in cylinder 1 and tested again with no change.

On the bright side, new intake seals seemed to have made a difference with the plugs. ?? Cylinder 1 isn't fouled like before and by now I would have already seen a good fouling.

I did pull the valve cover off over the weekend too, just for peace of mind, and visually checked the rocker arms, levers, springs, etc and everything looked good.

I've changed the oil a few times since last October and checked numerous times in-between, never saw any abnormal qualities (foaming, bubbles, etc). Also, coolant doesn't appear to have any oil in it and is holding steady since the valley pan change.

No oil leaks from the cover, no oil in the plug tubes either.

Lastly, I think the filthy condition of the engine due to all the [ignored] oil leaks/valve stem issues left over by the previous owner is why the plug threads look the way they do. Every time I do any work I try to clean them but seems nearly impossible to get all the gunk out of those groves (cylinder head).

[Skyline]

Well that compression test is NOT a favorable result. Usually, when adding oil does not bring the compression up, that means the leak is through a valve. This is better confirmed with a leak down test. When you add shop air to the cylinder through an adapter into the suspect cylinder, you can see where the air comes out; oil fill cap, tailpipe, or intake. I could see a scenario where a valve guide seal was bad for so long that the carbon build up is now preventing a valve from completely closing. Was this car exhibiting the classic signs of bad valve guide seals? (Punch the gas after idling a few minutes and get a big cloud of smoke out the exhaust; but otherwise running more or less normally.)

Assuming it's an valve leak, you might want to get a boroscope into that spark plug hole and see if you can determine what's wrong. If there's heavy carbon build up around the valves, getting that removed might solve this problem. I had previously suggested a way to do that.

[Toothbrush]

Originally Posted by Skyline

Well that compression test is NOT a favorable result. Usually, when adding oil does not bring the compression up, that means the leak is through a valve. This is better confirmed with a leak down test. When you add shop air to the cylinder through an adapter into the suspect cylinder, you can see where the air comes out; oil fill cap, tailpipe, or intake. I could see a scenario where a valve guide seal was bad for so long that the carbon build up is now preventing a valve from completely closing.

Second/new gauge + leak down test is the next 'to-do'. I'll post those results (maybe early next week) once done.

Originally Posted by Skyline

Was this car exhibiting the classic signs of bad valve guide seals? (Punch the gas after idling a few minutes and get a big cloud of smoke out the exhaust; but otherwise running more or less normally.

Yep, I didn't wait very long to do the valve seals once the smoke started (maybe a couple of weeks, after heavy research). No lights up to that point, and a couple of codes that I fixed. One for coolant, which was a rotted fitting for the upper radiator hose and one caused by a bad seal or crack in the crankcase vent hose (replaced same day). No other codes or Lights.

Originally Posted by Skyline

Assuming it's an valve leak, you might want to get a boroscope into that spark plug hole and see if you can determine what's wrong. If there's heavy carbon build up around the valves, getting that removed might solve this problem. I had previously suggested a way to do that.

The cheap boroscope I have stopped working, so need to pick another one up. Went to use it while I had the valve cover off and no picture. I know for sure the top of the piston is covered.

I've been looking at the kit you suggested and am 95% sure I'm going that route before anything else. I've keep hoping it's a sludge/carbon issue that just needs to get cleaned up.