Rough engine start

[bwilson4web]

Temperature: 63F
Time: 1:30 AM
Humidity: high
Car unused: ~48 hrs.
Most recent activity: oil change on Saturday

Went to run an errand and was surprised at a rough running engine start in my wife's ZVW30. It only lasted 3-4 seconds but it acted as if the engine had an intermittent spark plug failing. Weird.

Will let the car 'cold soak' another couple of days and see if it returns. I'll also check the spark plug wires and make sure the throttle plate moves easily. For good measure, I'll try to use the iPod recorder on the next couple of starts.

Bob Wilson

[a64pilot]

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?

[FireEngineer]

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

Wayne

[paprius4030]

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.

[Spartane]

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.

[bwilson4web]

Thanks folks. I had something like this happen with my NHW11 but I was using carb cleaner prior to starting. It was totally unexpected with the ZVW30.

FYI, it was an errand for "she who must be obeyed."

Bob Wilson

[ecrider]

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!

[tochatihu]

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

[FireEngineer]

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

[paprius4030]

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