barnum Posted May 3, 2016 Share Posted May 3, 2016 Hey guys, been awhile since I've been on here.My 02 R50 has been running rough at idle for a while now with P0300 coming up frequently (multi-cylinder misfire) as well as excessive oil consumption since I got it 3 years ago. Other than that the thing runs great. Finally really started digging into it to understand the issue and have come down to PCU failure of some sort based on the following diagnosis: - Air/fuel filter swap -> no diff - Plug swap (OEM NGK's) -> no diff - Power balance test -> found cyl #1 made no difference in idle rpm - Coil test -> OK - Check spark -> OK - Vacuum leak check -> OK - Dry compression test -> cyl #1/4 low (~50% of highest) - Leakdown test -> cyl #1/4 had leaked into exhaust stream, negligible leak in crankcase (piston may have shifted as I did not lock engine position) - Wet compression test -> cyl #1 jumped 22psi/cyl #4 jumped 70psi -> most likely bad rings/pistons/or cylindersSo, I'm at the crossroads of sell, engine swap, or repair. I want to know if this worn rings, compression loss is a known issue with VQ35DE's or if this is an outlier. Reason being, if I can get an engine swap done for $1500 that might be the way to go but I would be taking a gamble with a junkyard engine and don't want to get another if this issue may come back because of its prevalence. Anyone know a little better than me the known issues with these engines at high mileage?I'll have to perform the leak down again with the engine position locked to confirm or deny leak into exhaust stream.Info on VQ35DE longevity appreciated. Thanks. Link to comment Share on other sites More sharing options...
adamzan Posted May 4, 2016 Share Posted May 4, 2016 Sounds to me like the power valve screws may have dropped into it at some point. It has happened before. Just comp test the Jy engine before hand and you should be fine. Just check and loctite the power valve screws. There's a how to here somewhere. Link to comment Share on other sites More sharing options...
Slartibartfast Posted May 4, 2016 Share Posted May 4, 2016 +1 on making sure the JY engine has good compression before swapping. My dad checked around locally for a wrecking yard motor for his '03 and couldn't find one with decent/consistent compression. His had oil consumption too, though the engine still pulled just fine. Hopefully you have better luck at your local yards. Link to comment Share on other sites More sharing options...
barnum Posted May 4, 2016 Author Share Posted May 4, 2016 (edited) Shouldn't be power valves as from my understanding that was only in AT engines, I have a MT. Is oil consumption/worn rings a common failure on these engines? If so, I may not be interested in keeping the vehicle around. Which on the subject matter, what's the difference besides the mating plate between AT/MT and no power valves? AT engines will be much more available than MT. Is there anything else MT specific besides mating plate? Did the tranny coolant lines come from the engine or radiator? Found this image online from another poster in Nicoclub. I can't tell if those lines run into the engine at all or if just between the cooler and tranny. EDIT: Found another post that the power valves are actuated by the TCU so an "AT" engine swap into my "MT" Pathfinder won't work. Edited May 4, 2016 by barnum Link to comment Share on other sites More sharing options...
adamzan Posted May 4, 2016 Share Posted May 4, 2016 Why wouldn't it. Just use the intake parts off the old engine. The blocks and heads should be the same. Link to comment Share on other sites More sharing options...
Slartibartfast Posted May 5, 2016 Share Posted May 5, 2016 Not sure if common but certainly not unheard of. My dad found quite a few people who'd had the same issue when looking to fix his '03. I didn't get to tear that motor down so I have no idea what the problem actually was. We were thinking maybe valve guides because it only smoked on warm starts, but I've heard everything from ingested valve screws to the PCV valve somehow siphoning into the intake. And yeah, the power valves are in the intake, just swap that out and you should be good to go. Link to comment Share on other sites More sharing options...
Rebelord Posted May 5, 2016 Share Posted May 5, 2016 The power valves are vacuum actuated. In the MT they are just removed. Can swap intakes just fine. Sent from my SM-G920V using Tapatalk Link to comment Share on other sites More sharing options...
barnum Posted May 7, 2016 Author Share Posted May 7, 2016 Thanks for the responses guys. Planning to get a couple quotes on a swap then decide if I'll sell or repair. Intake swap should be easy enough and it will be easier finding an AT engine anyhow. Link to comment Share on other sites More sharing options...
Rebelord Posted May 8, 2016 Share Posted May 8, 2016 Ive been reading on Bob Is The Oil Guy forums about people with oil consumption and stuck rings. Lots of talk about doing soaks with Marvel Mystery Oil to free the rings. Bring back up compression and going about the day. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now