Rough engine start

It also happened to me once about a week ago. The car was built 9-2010 and has the original oil with about 3,000 miles on it. Anyways I started it around mid day here in San Diego, and the temp was about 65 outside. Ran it for about 15 seconds to move the vehicle and shut it down. ran fine. Then about 5 hours later, I started it and ran like the video though only lasted about 5-7 seconds and smoothed out. I am going to assume that running for that short of time is the cause. Has never done that before.

 

I like most everything about the car. (until today). Mine has less than 700 miles on it and that God awful noise commenced on the first cold start this morning. (with the ambient temp around 30 F) I had moved it around the driveway a couple of times yesterday to clear snow and ice, and have not driven it for a couple of days. I too, am concerned that if this becomes a habit, that the longevity of the ice could be shortened. I am guessing that it may be related to the winter formulated gas, the extra unburnt fuel in the combustion chamber from the quick start ups and shut downs, or possibly some moisture in the fuel? Has Toyota acknowledged that this is an issue at all? Dave

 

The tensioner works on oil pressure, apparently the Corolla with a similar engine system, has had problems with the tensioner. A search will bring up lot of info. A lot of cars have this kind of tensioner. The chain doesn't have to come off or skip, it gets loose and rubs things. The sound is familar to me, that's why I suggest this as a possibility. I am not saying I am 100% right, just trying to be helpful and suggest a solution that makes sense. Reading the posted conditions it occurs under, and that it goes away after engine runs awhile, fits the idea pretty well.

I suggested this quite awhile back but no one paid attention to what I said, which is fine.

 

Your theory is as good as any of the others including the two I posted earlier. But it doesn't explain why it only seems to happen after the car has been run for only a few minutes several hours before. The only thing that explains that for me is the "left over fuel" theory. We could be seeing the same symptoms with different causes?

Toyota certainly has been made aware of this numerous times and they have the resources to solve the problem. Why haven't they done so?

 

If it were really that simple, they would have released a TSB on it by now. Until then, they're going to remain silent just like any other companies including Apple.

 

I've experience rough engine start twice in 21,000 miles. So what? I suggest that it is impossible to NOT have occassional rough engine start if you think about what the car does: start and stop many times an hour, sometimes a few times a minute, in varying temperatures and humidities and other conditions. Once in a while, there HAS to be a bit of extra gas or the wrong air-gas mixture left in the engine. Moreover, I think most everyone who has experienced this hadn't driven the car for a few days, even more of an issue for residual gas in an engine. Our expectations are too high if we think we should have a perfect car.

 

I don't think anyone expects a "perfect car" but we do expect a car that doesn't try to shake itself to pieces when started. If you think this isn't important or that all cars do it I would think that perhaps you haven't experienced the problem. The first time it happened to me I thought the engine had come loose from the motor mounts.

I have owned a lot of cars and some of them had rough start problems when cold but this is far worse than a typical rough start. Toyota engineers need to look at this and implement a solution. Dealer service departments and posters on this site do not have the resources to solve this.

 

Apparently it's not a problem unique to the Prius so it seems to be an industry wide problem. However, the youtube video posted earlier didn't show the engine shaking itself to pieces (although it sounded horrible) or were you exaggerating?

 

There is no exaggerating in what I heard. It sounded so loud and violent, that at first, I thought the engine was toast. Very violent shaking. I hope you never experience it.

 

I'll take your word for it. Just didn't see any shaking in the video other than camera shake.

I probably won't ever experience it as I live in sunny California where there's basically no weather year round.

 

I thought I saw something (in this thread?) that suggested the problem may be simiilar to the valve timing gear issue covered under a TSB for Corollas and Matrixes. The engines are similar to the Prius's, aren't they?

I mentioned this to my dealer who said they've seen these symptoms but that it could also be caused by bad gas, which I find a little hard to believe. I've had engines run poorly and be hard to start on bad gas, but not try to shake themselves to pieces!

The valves being locked in warmed-up timing on a cold start seems to make more sense, doesn't it?

 

Wow, this finally happened to me at 6600+ miles (built in Feb. 2010)...I'd moved it around a little over a week prior in advance of a week-long trip (I very well may have turned it off before the ICE completed its warm-up cycle) that I took with a rental. I actually moved it multiple times and was half-expecting it to happen during these multiple power cycles, but I evaded it. After a week of sitting dormant in temps as low as 8F, I came back, started it and it underwent the aforementioned violent shaking/knocking episode between 5 and 10 secs before stopping. You can add me to the list of those who have suffered through it.

 

After 20 pages of posts, it's odd no one has proposed any hypothesis.

 

Sounds like cam timing issues similar to the current Corolla/Matrix (same engine .. just a non hybrid Otto cycle version)

What really surprises me is people get this with no MIL.

Of course it could be problems with fuel injection or ignition timing too. All of these things produce similar results.

The Engine ECU can detect misfires as unburned fuel releases a lot of HC but lack of MIL would indicate something else. Hmmm

 

If you search through all the threads on this, people have proposed many hypotheses.

 

I strongly suggest contacting Toyota to document this "Rought Start" issue at their Costumer Experience Center line, 1-800-331-4331. Request them to open a case and to document your experience.
In addition and more importantly, we all should be informing the NHTSA of the possible defect with the Prius. It is fairly easy, just complete a complaint form at :

https://www-odi.nhtsa.dot.gov/ivoq/online.cfm

all you need is your VIN.

I believe the only way to have Toyota take a look at this problem is by force.

 

Thanks for the link, I just filled out the complaint form. My 2011 shook violently last Sunday. Freaked me out, and I work on cars as a hobby!

 

There's been a lot of hypothesis including mine.

 

I also filled out the complaint form and called Toyota's "Customer Experience hotline"...Toyota tells me that its the first they're heard of the problem!

 

On 02-14-2011, I provided a ballpark summary of those PriusChat Gen 3 owners who've experienced this 'rough engine start' issue on another PC forum thread. I've recently discovered two additional threads and 19 new owners who've since posted about this problem.

Here are the current running totals:

SUMMARY(2010 & 2011 Gen 3 Prii only)

Main Forum: 4 topic threads, totaling 58 unique owner reports.

Tech. Forum: 4 topic threads, totaling 8 unique owner reports.

Maintenance & Troubleshooting Forum: 11 topic threads, totaling 106 unique owner reports.

GRAND TOTALS: 19 different topic threads, totaling 172 unique owner reports.

I'm fairly certain there remain other posts I've missed, as well as untold numbers of lurkers here who've experienced this yet undiagnosed issue but have not posted a word. These numbers represent only PriusChatters, which constitute a small fraction of worldwide Prii ownership. Thus, I am still convinced this start-up anomaly is not a rare occurrence, but is a statistically relevant issue and one that Toyota needs to address and then inform their customer base as to its significance and what, if anything, they intend to do to in terms of providing some satisfactory resolution.

It's sad to learn there appear to be official Toyota representatives and dealers who continue to deny the existence of this engine anomaly despite repeated communications from their concerned Prii customers.