Rough engine start

You missquote me. I didn't say "all modern cars need regular gas cleaner treatments". I said it is a common problem, preventable by the use of such treatments. My thinking is that it is cheap, easy and prudent preventive maintenance, likely to reduce problems down the road.

 

I wrote that because as far as I can remember, a few others have observed the shaking problem in similar conditions.

 

There is no more valve seating period on a new auto engine. For probably 50 years or more, the seats have been precision machined for an interference fit, including factoring a slight angle difference between seat and valve face for valve stem stretching under load. For American built auto engines at least, pretty sure Toyota isn't doing it different. AFAIK, I am reaching back about 40 years when I had to rebuild an engine and learned this was the "new" way, as opposed to lapping with abrasives.

 

I don't buy this carbon deposits story as it would require lots of short trip starts and stops to develop. This is something which happens (from what I can see from descriptions) only on restart when previous trip was very short on cold engine. Why don't people use EV mode for those short driveway maneuvers to prevent that from happening?

 

The car will not go into EV once the engine has cooled down, I don't remember the exact temperature but it's in the thread that discussed the stages of operation.

 

Tom,

Mine will go in EV mode after it is completely cooled down if I put it in EV mode on startup, right after the Ready light appears. This is what I have started doing when moving my car from driveway to garage. I have not had the rough start issue since moving it short distances in EV mode.

Dwight

 

Exactly, there is a window of several seconds after the ready light to press EV to use EV on cold engine. The only catch is, EV cancels over 10 MPH on cold engine. I use it all the time to back up from garage or parking lot and creep on a driveway. Saves me from wasting gas in ICE while doing that.

 

Thanks Dwight, I'll give it a try in the morning.

 

It often works, but it also will not engage if the battery is low (2 bars, as I recall).

 

OK you guys tell me if I'm doing anything wrong, or is my car somehow different?

This morning the car had sat in the driveway all night, temperature 46 degrees F. The battery was at 6 bars.

I put my foot on the brake and pushed the power button, as soon as the Ready light came on I pushed the EV button. I got the display that says "The EV Mode is Not Available at This Time". Tried it a couple of more times, same result.

 

Tom,

I have no answer for you not being able to go to EV. I get the message that EV is not available every once in a while, but most of the time I can go to EV if I hit the button right after the Ready light comes on and before all of the warning lights go off.

I do not know if the temperature has anything to do with it. It has not gotten down in the 40's here yet. IIRC I could do this in 30 to 40 F temps.

Maybe someone else will have an answer for you.

Dwight

 

I believe somebody else experimentally determined that if the coolant is below ~67°F/20°C, you can't enter EV mode when the car is first started. So no, there's nothing wrong with your car.

 

Thanks Mac, I had kind of thought it might be related to coolant temp but I wasn't sure of the number. I'll try to keep track of it and see if I can confirm the 67/20 degree number.

 

I didn't know that. EV worked for me every single time, but I keep the car in garage overnight. Will know more this winter I guess. I love the EV for slow and silent creeping in and out of garage and driveway.

 

LOL! Just one day after I wrote above EV failed to initiate. It was actually at the ambient temp of 75F and the massage showed "warm up" or something similar. I tried several times with the same result. Yet, one hr later, EV started fine (engine was cold again, same ambient temp). Clearly a bug in the software.

 

Tom,

LOL - ever since you posted this I have tried to get my car in EV in the mornings and have not been able to do so. I get the EV Mode Not Available message. The temps have been in the 50's and 40's.

I realized that when I use the EV the most is at night when I am moving it from the driveway to the garage. This evening about 6:00 it was 46F outside and I had not driven the car since 1:00 and it went right in EV.

I would have thought that the car would have cooled down to ambient after 5 hours. Without a Scangauge I have no idea what the water temp was at the time though.

Interesting.

Dwight

 

I just had my first "knocking" experience. I keep my Prius in a garage and it was around 60 degrees in there. I started the car up, and actually thought to myself if I would ever have the trouble of my engine knocking. Sure enough, somehow, it did it. I just pressed the pedal to change the RPM, and then quickly put it in reverse and it went away. So, if this happens to you I suggest you either press the pedal to rev the engine, or put it in drive or reverse and start moving. Seems to help, at least for me.

 

I've had this issue once before, but it was from a quick shut down after the engine was only running for 3-5 seconds. This morning, no such condition. The car was left in garage overnight and when it started it had this rattling/knocking issue. Powered down, and then back up again... no more shaking. I think, like some on this board, it is either a fuel metering issue or an ECU software flaw with MG1 operation.

I've reported it to my dealer and will see what comes of it. But yeah VERY annoying.

 

Update: I had actually recorded the start sequence with my DashDAQ by shooting the screen with my camera in video mode. During a normal start the SparkAdvance is usually between -2 and +2 TDC (that is what I normally see.)
This morning during the rough start...she started right at +8 to +10 TDC. I didn't see this until I played back the video.

There were also no DTC's recorded. Not even a Pending! ??? I'm at a friggen loss. I reported all this to my dealer and hope to get an answer back.

 

I read somewhere Toyota has engineers looking at this issue.... it is very odd most people are not getting any codes even though this really seems like misfiring.