Has the rough cold start issue being corrected?

I can't say that I've ever heard a "metallic" noise during my 4 events but after all 4 there was a strong smell of gasoline.

 

I am over 30k on my 2010 now and recently hard my third and fourth occurrences very close together, within a week of each other, both resulting from previous drive not being complete warm up cycle. I can confirm that in my two experiences pushing on the gas does temporarily correct this. I still don't bother most times, since even often when it's not had a complete warm up last time it was driven it won't have this rough start, but the last two times I "floored it" and the knocking went away, but the gas needs to be kept down for a short while, otherwise knocking comes back as soon as pedal released.

I think all my events have been ~5-10 seconds in duration.

We already have a thread on this, but Toyota has yet to address it in well over a year of reports, so as far as I'm concerned the more we complain about this the more likely we are to get an official response.

I'll believe it when I see it...

Heck no, but chances of it happening are slim. Even with my current car I suspect it's causing no real damage since it happens to infrequently.

I used to have a Maxima and from basically the day I bought it used until I sold it, 100k miles later, it would often have an awful metal on metal screech upon starting. It appears this was the timing chain tensioner. It was a terrible sound and one would think it was going to cause premature issues but at 135k the issue never got worse (didn't always happen, happened more when it was cold) and the engine continued to purr like a kitten.

Agree. As I said in the other thread, I refuse to spend one iota of effort (other than posting here of course!) on trying to avoid this by extending warm up cycles or otherwise inconveniencing myself.

 

I just went to my dealer last Saturday for my 20000 mile service. There is in fact a TSB to cover this issue. It was just released last week. It involves replacing the left side engine mount. I am not sure this will fix it but I am getting it done anyway and will keep you all posted.

 

Link? I hear about this mysterious TSB but nobody has yet posted a TSB that I've seen that addresses start-up knocking in a 2010+ Prius.

 

I haven't had the issue yet. It has been very cold for Atlanta the last two mornings, below freezing yesterday morning and I had no issue whatsoever. Perhaps they did the update to the 2011 model before I bought it?

 

Seilerts posted this about a week or so ago.

http://priuschat.com/forums/gen-iii...n-engine-knocking-startup-t-sb-0204-11-a.html

 

Took mine to dealer and although the knocking did not occur, I did have several YouTube videos with me that detailed the problem.

The service techs had not seen/heard of this problem before but were all quite interested. The dealer notified tech support in California and they approved my getting a new intake manifold after watching the YouTube videos. My new intake manifold should be available in a week or so. I'll keep everyone posted after it is installed (...to be covered under warranty of course).

What I find most interesting is that the dealer, located in the greater Baltimore/Washington area, had not had any reports of this problem. This forum does not have that many users, and the users of this forum are scattered all over the world. With so many users experiencing this problem you would think that the percentage of owners NOT on this forum that are having the same problem would be quite high in numbers, no?

Anyway, I think Toyota does know about this problem and rather than starting a campaign to correct all the problems they are simply waiting to fix them as the problems get called-in. With all the recalls and problems Toyota has had in the past 5-7 years it doesn't surprise me that they want to keep this issue quiet for as long as they can. Quiet from the press anyway.

 

So, has it problem happened again SINCE you delined to have the new intake manifold installed?

 

Thanks!!

I can say with complete certainty however, that the 32F cutoff mentioned in this was not the temperature when I first noticed this--a morning in June, 2010. Not sure what the temp was but well, well above 32F.

I may have them perform this TSB when I'm in there in March for inspection, though, unless they need proof somehow that my car suffered from it.

EDIT: That original thread says the TSB for mount is to address a different sound. Makes sense, as what I hear--the metallic banging--really does sound like mounts couldn't be related to it.

 

Yep, I agree -- a COMPLETELY different sound, and a COMPLETELY different problem! I was trying to stress that in a post a few days ago; asking people in the forum not to get confused about the two!

 

OK guys, its official, the TSB is out for the engine knock in the morning..., the problem is the intake manifold..., the issue is when, condensation builds up in the egr it gets sucked into the engine in the morning causing a misfire, the new manifold was revised in order to address this condition..., a brief knocking after cold startup.... TSB number:0010-12

 

Based on past performance, if service observes the listed fault codes, would they automatically perform the repairs or would they disregard the codes because the problem hasn't been reported?

What about the motor mount? Is that repair also required?

 

No the motor mount is a different condition all together.., it is a buzzing noise for an extended time while the engine is running in extremely cold temps..., they wont automatically perform the repair unless you complain about the brief knocking on a cold startup...

 

So you know for next time, if you press the power on button once with foot off the brake, it will be in audio accessory mode (the engine will not start at all). You will not be able to move the windows though.

If you press Power button twice with foot off brake, the display will come on and you can roll windows down and still the ICE will not come on (it is not in hybrid ready mode).

From either of above modes, if you put foot on brake, press power button once more, it goes into Ready mode where you can drive.

No need to fire your ICE (Ready mode) just for radio, iPod, or opening windows, but power down if you leave the car

 

EGR condensate and misfire seem to make sense.

But why would a misfire result in mechanical noise? Is the angular rotation of the crank so irregular that that it slaps the timing chain around?

 

The 'mechanical' noise you hear is the damper in the transaxle, it is absorbing the harsh vibrations from the misfire and it makes that noise.

 

As I recall, this unit resembles the driven plate of a conventional clutch having springs in a circumferential arrangement. So the springs bottom out during the misfire? Are there any reported failures of this unit?

 

No there hasn't been, it was designed to take some abuse (because of the multiple engine starts/stops that prius does every driving cycle)