My girlfriend bought a 2000 1.8l mr2 last week and it has the following issues: Blue smoke on WOT, Wont rev past 4500rpm (feels like a rev limit), Seems to be blue smoke escaping from the block as well as the exhaust. Plugs are covered in oil and caked within 20mins of driving, Feels like 40hp (not 140hp!). Lots of pressure coming from the oil cap port when the cap is removed with engine running. The top of the pistons are gungey black and caked with burnt oil. Engine in question is a 1ZZ-FED (which are notorious for pre-cat failure, burning oil, doing in piston rings and big ends). Now - before i fall to internet hearsay and buy a complete new engine tomorrow..... there are a few things that are really baffling me and making me think it may not need a complete engine!: 1). It idles perfectly. 2). It doesn't miss fire between 1000 and 4500rpm (in neutral or driving). 3). it's only got 100K miles. 4). I inspected the pre-cat and it looks intact. 5). I compression tested it tonight and i got 175psi across the bored!! (which i couldnt believe). 6). I pulled the rocker cover off and nothing looked suspect - ie no blow by. 7). I inspected the rocker oil breathers and they were relatively dry. 8). The car was really low on petrol when purchased which led me to think initially the lack of power may have been a blocked fuel filter, The compression test really threw me..... i thought it was rings for sure. So now i'm think one of the following (or all 3 combined): A). Valve stem seals letting loads of oil into the cylinders. B). Blocked fuel filter causing the lack of power. C). Dodgy MAF causing the 4500 rpm rev limit. Any opinions???
Anyone? Forgot to mention - no engine check light is on. I'm starting to think that a seized PCV valve on the rocker breather could cause huge positive crank case pressure that would force oil through the valve stem seals, and that's why it's burning oil and oil is getting into the cylinders..... This would explain the good compression results (as the rocker cover was off for the comp test. Going to run with an open breather tonight and see if that makes a difference. Still at a loss with the 4500rpm rev limit though.
Leak down test will tell you if its valves or not but sounds like it may be. Wont have any effect on the rev limit though I imagine so might be another issue probably to do with the fuel like you mentioned
PCV and worn valve stem seals ? Could the knock sensor be pulling the timing because it it is picking up knock created by the oil contamination in the cylinders (lowers fuel octane rating) ?
Presumably you know nothing of the cars history ? Who did you buy it from ? Oil getting spewed everywhere could be as simply as a crankcase breather not hooked up correctly. have you checked the intake passageways ? Are they oily ? You say plugs cake within 20 mins....from brand new plugs ? Post a picture. Is the engine filled with the correct amount of oil...and not filled to the brim or something equally stupid ? As for CEL etc...is there even a bulb ? Viewing lave data for any anomalies would be more useful than any fault codes. Low rpm limit could be many things, from an actual fault to a deliberate action from the ecu because something is making it unhappy...again a proper interrogation of the ecu should reveal anything odd there.
When I bought ours it wouldnt rev past about 4.5K - no error codes either. Replaced the AFM and it was fine, might be worth a try The other stuff, Id have said rings as well but if its got compression Im at a loss, ours is weeping from rocker cover gasket so chucks out smoke when it hits the manifold but if your plugs are oiling up, who knows?
Well - bit of an update (and thanks to those who gave decent advice): I ripped the main cat out - totally clogged with burnt oil/carbon and also one of the pre-cat's from the manifold has shat itself and also partially blocked the main cat. That was the 4500rpm limit problem - engine was getting choked. Took it for a spin and full power again (very fast actually). So thats the power issue sorted - but i still have the oil in the cylinders issue (which has gotten worse now because there's no back pressure.... So now it's missing in the low revs and the plugs are completely getting soaked in oil. So i did a hot compression check this time..... 175, 175, 200, 175. good results and i'm not really worried about the higher reading on no.3 as it's boarder line within specs and i reckon it's higher because that's the most oil soaked cylinder. So now i'm thinking it can only be one of two things..... 1). Valve stem seals. 2). Piston rings. I'm leaning more towards stem seals (as i think the huge back pressure could have knackered them over time). Also i would not have thought worn oil rings could let so much oil in (like, tons of oil!). No engine check light, no PCV issues or breather issues, no oil in the intake, no overfilling...... Anyone think it could be the rings!?
So did you check all crankcase breathers and check the intake to see where any traces of oil actually start appearing ?
ya nothing. Turned out to be completely knackered valve stem seals..... which happened because of a totally blocked cat and the car being driven like that for months. I opted for a replacement engine rather than refurbish the head.
