Every morning I drive about a quarter mile and then wait at a stoplight. This is when the engine first shuts down. There is always a very strong vibration on this shutdown. All future shutdowns and startups are very smooth. Is this normal?
Yep, sounds normal. It's more noticeable when the engine is cold. Also, I sometimes encounter that kind of vibration when situations cause the HSD to get a little indecisive about whether to keep the engine running or shut it off. For the most part, I experience very little (if any) vibration. That's pretty awesome considering the engine is always engaged and it's the motors that have to compensate for engine RPM changes! - Justifyd
During warmup, the hybrid system doesn't necessarily manage the engine as "tightly" as at other times. When you're in full normal operation, the hybrid system also keeps very close track of the engine's crank sensor and thus has its own copy of exactly where the engine is -- and in fact uses the motors to reposition it about 9 degrees before top dead center at shutdown, to better facilitate spinning up again later! Sometimes the roughness is from when the hybrid system doesn't bother to do that in some instances, and some is from it taking close control the first time -- sometimes you can actually feel the engine shut down and then do another little lurch right after that. Guess what, it's actually the electric motors doing that on purpose. . A line from one of my training slides says "HV ECU gets NEO copy of CKP for RPM and TDC" how's that for alphabet soup? It's true, though. . _H*
Guys I have the first generation prius. It runs great and I love the car. This vibration issue is something I noticed too but recently I have gotten alot of problems. When I start up the engine idles ar per norm but then after a few seconds the revs seem to fluctuate, my battery indicator (HV) goes from a low level to full green bar in an up and down manner. The vibration sounds and the engine then seem to free wheel, and the revs seems to increase. Accessing drive mode does not result in the car moving. It just seems to be out of gear. I have checked from the aux batteries, the HV batteries, the ECM etc.. even the pedal sensors and cant find a clue. My investigations so far has shown: (1)no fault indications, (2)the turtle icon is on after a few seconds into start up (3)and the knock sensor seems to be the one which is picking up the vibration and sending a signal to the ECU. My question is this: is it possible that the transaxle is damaged or some other component in the coupling of the PSD and the ENGINE and MG1, MG2? I need help. Where I live there is no authorised toyota dealer, and the lots of mechanics here not familiar with this baby.
I would also say, "normal". I have had my 2006 for 2 1/2 years and it still does it from time to time. No rhyme or reason that I have spotted yet. Don
