Everyone's favorite p0300
 

I'll give you the history first. About 2 months ago I pulled the engine out to put JUN cams, wiseco 10.5:1 pistons, and maramello rods in it. I did the work myself since I'm a technician. I have full Megan exhaust except the stillen headers, no cats or pre cats just open tubes. The intake's are Injen's, I have been tuned but since this problem was found out on the dyno, who knows how accurate it is....(It's uprev)

For the first 500 break in miles everything was ok. Then once I started getting on it more and more I noticed fuel in my oil, only slightly at first(the CEL light had been on because of the O2 sensors, so I thought anyways,) Then I noticed it was losing some power. So I checked all the plugs and only #6 was fouling, except that it was caked in oil and fuel, So I thought "****, one of the rings not be right". So I preformed a compression and leak down test, after I cleaned the cylinder, 220 psi for 20 minutes. Not the rings. The rings just are not sealing when the walls are coated in fuel. Now I checked the injector pulse with a noid light, it was no different then the rest. Changed back to my stock injectors and problem still there. Moved the coil and plug, problem still there. Since I don't have access to consult III(I work for Honda), I can't check some of the live data since Uprev has the worst data feed I've ever seen, thanks for giving me bank1 and 2 not the whole ******* engine.

I ordered a coil since one of them was weak anyways, and will replace that today. I'm also going to replace the 02 sensor that was throwing the performance code from a while ago, but it said bank 1, #6 is on bank 2(I think unless Nissan just decided to do things differently). I'm also going to try a different plug (e3's, cause they work wonder's in my 77 280 with a turbo on it.) Also the coil(no matter which one, makes good spark on #6, same with the plugs.)

So any idea's out there on the problem, I'll update you guys tomorrow on everything to see if the 02 magically fixes this. But with out some data or Nissan's theory of operation, I'm kinda pissing in the wind right now.

I can't help. I'm just here to ask a stupid question. Isn't the stock compression 11.5:1? You rebuilt the motor for a NA car with lower compression pistons?

It's 11.1:1 if I remember correctly, Nitrous is on the way but only once it's right. I have the 100 shot for it. I just haven't hooked it up. Hence the lower cp and forged internals.

Ok, you built the motor for spray. That makes more sense. :tiphat:

Yea, I was going to use the kit on my VR-4, But after I broke the 3 transmission, I said **** this car and tore it apart and am parting it out. NO MORE ENGINES THE WRONG WAY FOR ME.

I just checked my AFR on Bank 2, sensor 2 reports it as a 29-30. That is probably my problem.

Are the rings on those pistons free floating or do they have guide pins? I remember something back when I was learning how to build motors that if the piston rings and the oil scraper 'line up'.. like where the ring ends are aligned with the one below it, etc.. you can get blow by. It could hold when you do a leakdown test on it, but when its running it could be a different story. Have you pulled your oil pan to see if theres anything in there?

before your problems what did you dyno at with this setup? curious as I don't think anyone has dyno'd and shared that has full bolt ons and jun cams. good luck fixing your issues.

I never got a good run, so I have no idea.

This P0300 is 99% of the time related to a LEAN misfire, id start there and not on fuel side, vacuum leak, the consult 3 is great(i run a shop that has one), but i would definitely start looking for a lean issue, intake leak throttle leak vacuum leak etc.

Didn't even read the thread but if you're trying to wrap your' head around p0300, don't unless you have consult3, you can see even a fraction of what the car is looking at to throw that code. For referance, i had a p0300 and after 3 months the dealer finally figured out the thrust bearing was worn and the slight vibration from the crank moving made the car throw the infamous "Something is wrong but I don't know what" code because it was getting picked up randomly by the knock sensors. They had to replace my motor to fix it, If you have narrowed it down to no spark on cylinder 6, then you only have about 10 feet of wire loom and the ecu left to check. Hope you get it fixed eventually that code is a bitch.