My Sienna van has one of the earlier VVT Toyota designs. Engine started bucking like a mad bull and tossed the p1354 code for a faulty VVT oil control valve. Luckily I limped it home before it got worse. I ordered the OEM unit for the left bank cam phaser and installed it.
One thing that seemed strange is that the RPMs went really high after installing it on a cold start. Usually it doesn't go over 2K, ever. But right after replacing the oil valve and starting the engine, it went up to 2.5K RPM. I then drove it for a week and each cold start after that was normal at about 1.5K RPM.
Today, I installed a new OEM right bank valve proactively, since they tend to go out around the same time. Once again, on the cold start after the swap, the engine raced up in RPM to nearly 2.5K. What could be causing this? Does removing a VVT control valve allow oil to drain out of the phasers, making them a bit off until the engine has run a bit? Or does the engine have to re-learn the advancing and retarding of the cam phasers once a new one is installed?
Also, curious if anyone has any ideas on why the VVT oil control valves would be more likely to be faulty in cold weather? I've read reports from others with the same engine (Toyota used it on a massive number of cars/vans/SUVs) that the engine started acting up in cold weather due to failing valves, but not in warm weather. The left bank (front) valve on this engine sits a bit exposed and probably gets a good blast of cold air when driving down the highway. Maybe the cold is just enough to cause a failing VVT valve to become extra sticky and poorly performing? The engine actually did toss a code for the left bank a little over a month ago during the previous cold snap, but went away and didn't cause the engine to run poorly in warmer weather, but then ran perfect with no codes until the next cold snap.
One thing that seemed strange is that the RPMs went really high after installing it on a cold start. Usually it doesn't go over 2K, ever. But right after replacing the oil valve and starting the engine, it went up to 2.5K RPM. I then drove it for a week and each cold start after that was normal at about 1.5K RPM.
Today, I installed a new OEM right bank valve proactively, since they tend to go out around the same time. Once again, on the cold start after the swap, the engine raced up in RPM to nearly 2.5K. What could be causing this? Does removing a VVT control valve allow oil to drain out of the phasers, making them a bit off until the engine has run a bit? Or does the engine have to re-learn the advancing and retarding of the cam phasers once a new one is installed?
Also, curious if anyone has any ideas on why the VVT oil control valves would be more likely to be faulty in cold weather? I've read reports from others with the same engine (Toyota used it on a massive number of cars/vans/SUVs) that the engine started acting up in cold weather due to failing valves, but not in warm weather. The left bank (front) valve on this engine sits a bit exposed and probably gets a good blast of cold air when driving down the highway. Maybe the cold is just enough to cause a failing VVT valve to become extra sticky and poorly performing? The engine actually did toss a code for the left bank a little over a month ago during the previous cold snap, but went away and didn't cause the engine to run poorly in warmer weather, but then ran perfect with no codes until the next cold snap.