Jerking after taking off the gas and more..

Any warning lights?

Is your problem consistent, or intermittent?

The nature of these Atkinson engines causes them to occasionally run a little rough on start up and shut down, especially when cold. So if it's relatively rare you have nothing to worry about.

 

Hopefully, this is going to be a very interesting thread. Here's something I've noticed, but haven't really brought up for discussion.

I've had around (10) Gen 2s in my driveway at various times. I've built a handful of HV batteries for them and several for other forum members. On some, I've used modules from brand new OEM Gen 3 batteries and also made some using modules from very low mile Gen 3 and Gen 4 wrecks.

I've noticed, at least on my cars because I have plenty of before and after time behind the wheel, that a Gen 2 with an aged HV battery can act just like the OPs symptoms when the engine shuts down or starts while driving. Install a 'new' battery and it goes away. I've always noticed how much different the transitions are after a refurb. Why? I don't have a good answer. Unfortunately, it could be a bit expensive to try battery replacement as an experiment to see if the symptoms get cured.

 

Yes I have a Gen 2 well got four of them here but two of them have had batteries and when batteries were failing or falling into the pitfall of failing a lot more snatching and jerking a clunk when the engine cuts off a noticeable one soon as the battery went in Bam back to like brand new so when I go to buy one of these cars now and get it running in the parking lot where it's been sitting for God knows how long because the people whatever I'll get it started in the parking lot drive it around a little bit and will notice that very quickly of course I'm buying the car for a couple hundred dollars mainly because the hybrid battery probably is dead the reason the cars parked.

 

Adding another data point to confirm this observation. Before reconditioning the HV battery for the first time, it had a rough transition to and from the ICE. After reconditioning, back to very smooth and unnoticeable. Subsequent reconditions were done when fuel economy started to tank, but ICE to EV and EV to ICE transitions were still smooth so have not had the phenomenon again.

 

Interesting line of thinking... I guess the next step in your process would be to look at the health of the hybrid battery via an inexpensive Veepeak or Panlong OBD2 reader so you can run phone apps like Dr. Prius App and others to get a sense of hybrid battery health.

Or perhaps more directly, how does the state of charge screen look while driving? Does it move rapidly from full charge down to one or two bars very quickly, or does it stay pretty stable? The more stable the charge level, the healthier the battery pack.

 

This makes me realize that every time I hear the engine start up in a Prius that's stationary or moving slowly it consistently sounds faster and more efficient with a www.projectlithium.com/?ref=9qLPw battery pack than it sounds with an old OEM pack. Perhaps the availability of more amps more often makes the motor starting the engine sound more robust than an old OEM pack depleted down to one bar?

 

It's funny how that would work too because when the Prius is moving the reciprocating mass is always turning so starting of the engine is not like a starter motor turning the reciprocating mass and adding fire and fuel to start it I reciprocating mass is already turning with the electric motors etc all the Prius is doing is flipping a fire switch that turns on the coils and the fuel pump I would have to guess. That's why it should be very smooth and all this and that because everything is already turning The Prius is just flipping a computer switch for the fire and the fuel pump and then it turns that off when the computer dictates right? But I do notice in a car with a low battery like you noticed when it's in the magenta red area everything is real sluggish duh. So I guess it would make sense as your battery gets more and more depleted things may get a little clunkier I imagine the relationship of the 70 horsepower electric motor to the I don't know what 90 horsepower of the gas engine becomes less of a match with lower state of charge possibly.? Something along those lines so having more battery power probably a good thing I'd like to have a battery that would be as 2x thick as the battery we have now. The room is not the problem at all I don't need that space I'm going to take up back there at all so I could literally have two battery packs stacked on top of each other not sure how it would get them wired or whatever I would just like to buy some kind of battery that's based on the 211 volt nonsense but with double the AH or whatever that would be called I don't care if it's twice as tall that's okay The bus bar arrangement would be quite wild or the module assemblies would be quite different would matter to me.