Rough engine start

There have been a couple of reports of "banging" under the hood during cold starts as well. David (blind guy) , I believe was one of the ones that had the problem. Mis-firing could lead to backfiring, which I could see how that would sound like banging?
On edit, doubt the throttle plate has anything at all to do with it, I would assume no movement of it for idle, and pretty sure each coil pack is monitored so I don't think it could be ignition. I think fuel delivery, maybe even an overly rich mixture due to the evap system and or that charcoal pad above the air filter?
What are you doing out after midnight?

 

Bob, let us know if you can repeat it. I had that happen once and can't repeat it.

Wayne

 

Hi Bob, I had the same thing happen to me once last year with my Gen. 2 Prius. I thought it was gonna rip off an engine mount. O f course it never happened again and there seemed to be no explanation for it. I think the Prius just has a lot of wierd one time things happen to it to keep us Prius chatters from getting bored LOL.

 

Did you by chance, at some point earlier in the day, start the car cold to say move it around on the driveway and then immediately turn it off?

I've had several cars (non-Prius) run rough the next time after doing this to the point where I don't like jockeying the cars without warming them up (especially in the winter time).

I don't know what it is, but I'm speculating that it has something to do with the fuel injectors holding a lot of cold fuel that would normally evaporate, but doesn't because the engine is cold.

 

How timely of a posting... this just happened to my 2010 Prius. I pulled the car out of the garage on Sunday to wash it, and the engine kicked on for about 30 seconds. I turned it off, washed the car, started it back up to pull it back into the garage. The engine again ran fine for about another 30 seconds until it was back into the garage.

As I started the car Monday morning to go to work, it badly misfired the entire time I backed down the driveway and into the street. It continued for about a block as I drove forward until it gradually diminished and eventually ran smoothly. There has not been a repeat incident since then.

I didn't do anything unusual when washing it (regular hose washing--no water into the engine compartment), so I was stumped at what might have happened until I read this post. Thanks!

 

Any cylinder misfires would be logged, yes? I can not imagine other events that could cause the extreme symptom that e.g. paprius4030 reports.

 

Just happened again yesterday. 6:00PM, ambient temp 60F, engine temp 103F, SOC 4 bars, driven .5 miles. I was proceeding from a stop light and when the ICE kicked in in had a pronounced knocking sound. Not as severe as the first time, but not normal. If your use to a Prius ICE kicking on, when the engine first gets spark and starts you can sometimes feel a very slight catch to the engine, this was worse and continuous for about 30 seconds then just stopped. No indications on the dash and no codes on the ScanGage.

Wayne

 

I didn't get any codes on my scanguage when it happened to me last year either.

 

I just experienced this over the weekend. I was over in eastside Washington where the overnight temps were about 20F, down from my usual 50F. It happened twice, each in the morning on first start. The first one had me yelling 'whaat thee fuuu***!'. Definitely felt like a normal misfiring on a cold start, but the ICE kept on going instead of stalling.

Now back in Seattle, I am no longer having this issue.

 

+1

This happened to my Gen-3 this morning. Last night I pulled the car out of the garage to let my spouse have the Prius' space to load some junk into her SUV.

This morning I thought the thing was going to shake itself to pieces at startup. Ambient was +/- 50F, very high humidity. No other unusual circumstances other than, as I removed the car from the garage last nite, the ICE ran for maybe 30-45 seconds and the car was subsequently shut off for 8-10 hours before a restart.

Very curious; I would very much like to know why Prius seem to be susceptible to this.

(FWIW: I've got ~3,000 miles on it, so it's not like the car's suffered a lifetime of abuse.)

 

Everyone the experiences this issue and all the others should report it to the dealer/service department or Toyota directly to get it on record.

 

Did that Monday. Tech said he never heard of it. He called Toyota and they said they never heard of it. at least i have a service record of my complaint.

Wayne

 

Add me to the list of people who have had this happen.

 

Had one night where temperatures were below +20 F. and the next morning I had the same problem. Engine was quite rough and it sounded like the exhaust pipe was rattling, lasted about 15 seconds. No repeats but it has been warmer since then.

 

I'll add to the spectrum of conditions. We were gone for 15 days. Upon startup, a WEIRD noise from the engine lasted only 6 seconds or so. Totally unexpected and almost like it never happened--but it did.

 

After I washed my Prius tonight, I decided to make a spin around apartment complex where I live. Pushed the start button and a strange noise came from engine.....just of second or maybe 2; however, it made me nervous....
I opened the hood and check if there is any water on any parts; however, everything was okay.
Drove the car for 4-5 miles and it seems to be okay for now.
I will check it tomorrow morning when I go to church...
I believe it has something to do with temperatures 50F and the fact that I washed it....
Probably, we will find new interesting sounds in the next a few months....with temperatures going south...
The Prius is really a unique car

 

Seems to be a little of a trend. Moving the car or running it for just a short time, then turning it off and starting it the next day seems to aggravate the condition. I'm sticking to my too rich a mixture theory, but to be honest too lean would do it as well. Don't think it is ignition or any other electronics as that should throw a code.
Most likely will end up being a anomaly of the car, just something they can do from time to time.