NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10

Just the other day - mine did do it once - but only for a half a second ... almost like it fouled a plug but cleared right up.
this occured on a rain-ish day with moisture in the air - and I had shut the car off before the warmup cycle was complete --- came back from lunch shut it off --- it set for 5 more hours - and at 5 when i went to leave work -- it fired up sputtered a couple hits...and immediately went smooth... didn't have to shut it off or anything ... and no, no warning lights or anything.

I almost wondered if it weren't pre-detination in the manifold ... since... on the atkinson cycle engine - they leave the intake valve open during the first bit of compression stroke - which blows some intake air back into the intake - i'm assuming this is to help promote atomization of the fuel - and get a better air/fuel mix ... but, when cold and with cold air or cooler air -- the fuel doesn't mix or atomize well leaving a "rich" mix in the intake... causing it to backfire...

i'm not sure i explained quite as i am theorizing - but maybe you follow what i'm trying to get at?

 

In your case, it could very well be. You will know when you get an event like many here describe. It literately sounds and feels like someone is clobbering the engine with an 8 pound sledgehammer. It is quite violent.

I have had a few rough starts since the replacement but nothing like what happened twice before. Even know when I can sense a rough start coming, I cringe thinking it is going to postal on me.

 

In an early post - when I first joined PC and was shopping for a prius - I ran across the issue... once.

I was looking at the liftback and the v - and when the saleman and I climbed into the brand new v they had on the lot - and i hit the start button -- it did the knock. caught the salesman offguard too -
yeah, it sounded like throwing a bunch of pinballs into a dryer and turning it on ...

he reached over and hit the stop button -- waited half a second then hit the start button again - and it was fine...

for a second - i almost thought maybe the AC motor tried started the engine in reverse...
never had an issue after that -- and i luckily haven't had one in my new car ... purchased in july...right off the delivery truck.

 

Hi friends,

Well the other morning here in Ohio it was raining all night and the temp dropped to around 30. Next morning started up the car and - knock knock - so loud and rough the car shook for 30 seconds till it worked itself off.

If that didn't set off a DTC, I don't know what will.

Anyway - went to Toyota service department here to have them check it out. The service adviser mentioned they had to do one of these already before so he seemed a little familiar with it. They looked into it and sure enough there was a DTC present. They ordered the parts and will be doing the repair as soon as the parts arrive.

 

Join the club!

Glad they didn't beat around the bush and got on it. I have not had a re-occurrence since.

 

After driving from Ohio to Florida, I started my Prius the next morning and experienced the violent engine rattle that other posters have described in this thread. I've had this happen twice before, but there has not been any consistency in temperature or driving conditions to come to any conclusions. In fact the TSB indicates the temp needs to be 40 or below which was not the case during the last episode. If fact it was more like 60. So I printed out the TSB from this thread (thank you seilerts), and took it to Cramer Toyota in Venice, FL. where I purchased the car. They were incredibly unhelpful. They said that the DTCs were not found, and there was nothing they could do. They even implied that I was making the whole thing up. I then informed them that I would post my experience on PriusChat (which they knew nothing about) and never return to their dealership for anything. So the questions I have for my learned brethren are the following:
1. Should I contact Toyota directly of this issue and my experience at Cramer Toyota?
1a. If so, what Toyota department is best for this issue?
2. Should the DTCs have been stored in my car so they could see them or do they only show up during the event.
3. I am concerned that this violent shaking will eventually damage something in the engine compartment (i.e. motor mounts). Is this a reasonable concern?

I learn so much from reading what this community posts. I sure hope someone can ease my fears.

 

From what I have been following on here -- no, there doesn't necessarily have to be a DTC ... The DTC is only made when the computer "sees" a parameter out of spec. like say - an 02 sensor fails and it can't see there is unburned fuel in the exhaust --etc. then the light would come on and a code would be stored. most computers today running obd2 or later - will store a "snapshot" when the light comes on ... the tech can then hook up a scan tool and read that data - to help see what was going on at the time the even occured. from my understading - this knocking issue - isn't setting a code... for whatever reason - the computer isn't seeing the misfire event. I honestly think - it has to do with a crank sensor - and in certain rare conditions - the computer thinks it's in time - when really it may be 180 degrees out of timing ... that's what it acts like it's doing ... I've seen this before - when I helped my dad rebuild an engine - and we dropped the distributor in - lined up to the mark -- problem was - the piston was on bottom dead center not top dead center... it rattled and "dieseled" - as the shop term was ... pulled the distributor - realigned it - and it purred like a kitten.

Since everything is electronic today - they have crank sensors - that measure rpm, and tell it where position 1 is ...
maybe the prii have 2 on the crank as a redundant - but the computer see's the wrong one first and times the spark to that ... could explain it - just theorizing... again.

for what its worth...

 

You can file a complaint with Toyota Customer Care. That's what I did and they asked what I wanted done to fix the issue. I explained I wanted the TSB done and I had video showing it happening to my Prius. Couple weeks later the dealer had the part in and I got the TSB performed. Like I mentioned in another thread, it use to happen for 15 to 20 seconds now it happens for about 3 seconds. So in my case it wasn't a total fix.

 

Oh no's! Mine starting rattling for about 15 secs or more when I turned it on. The temp outside today was around 45 deg. I just brought it in to Toyota today to take a look at it. I also gave them the TSB just incase. I hope they fix it can fix it. *crosses fingers*

 

update. Boo, they couldn't reproduce the problem so they're not going to fix anything. The temps the past few days have been in the low 30's when they would start up the engine. Now that I think about it, I washed my car the day before maybe moister got into it.

 

I'm really sorry to hear that, friend. It's like they think we're going in there on purpose or something. If my car never made the knocking sound, I WOULDN'T want them doing a 7.5 hour major repair to my car! No touchy!! Unfortunately mine has it bad so it needs done. Don't know why they'd think we would BS them....

 

because it's wrranty work that probably only pays 45 min. book rate... which is all they get no matter how long it takes.

 

Oh great. Our's just started doing this. Three times now in cool weather. Guess I'm going to make an appointment tomorrow and see what comes out of it. Wife drives this car, but it did happened one time when I started it about a week ago. It's quite the racket, but only lasts a couple of seconds or so. Ho-hum.

 

I decieded against doing the TSB on my Prius since people say it doesn't totally cure the problem. The FIX seems to be to just put it in D or R as soon as it does it. That makes it stop.

 

How did you make out with the issue? Has it happened again? I am assuming it knocked, etc at start up before part replacement.

My dealer wants to actually hear the problem before taking such extensive effort to replace. They also stated they have never had this problem and have never swapped out these parts. Ugh

 

Has anyone had JUST the intake manifold replaced and NOT the R&R right rear mount? I am only having the intake manifold done today, but am worried I'll still have issues of knocking/vibrating if I don't get the R&R mount done as well -- I haven't noticed any major vibrations from the engine, just when it's actually knocking.

 

They first did my R&R mount. That did help to smooth out the starts and in general the noise from the ICE. Then after negotiating with them (about a weeks time), they installed the IM.

I think the mount replacement helped a lot in terms of starting vibration and noise.

 

I have taken my 2012 Prius in three times and they could not get it to duplicate the shaking and noise. The third time I refused to drive it because I work an hour from home in a rural area and was afraid of the car quitting. After insisting they gave me a rental car and then said Toyota had said to replace the manifold. They did and a week later the rattle and noise happened again this morning and this evening. Now the check engine light is on. I called the dealer and they said Toyota came and decided that it is bad fuel in the area and they will clean out the fuel system to get the carbon build up out and the estimated cost is $200.00 to me. Then there is a specific fuel they want us to use. They say it is not a Toyota part so they can not cover it. When I bought the car there was no restriction on the fuel just regular gas. In Tuscaloosa, Alabama the only gas station that sells gas without ethanol is approximently 20 miles from my house and not in the direction of my job or near a business I frequent. The car was manufactured to burn regular gas per the service technician and that is what I have put in it. So why I am responsible for the repairs?
Is anyone else having these problems?

 

All through this thread people have had the same problem. Now with the check engine light on, that is something they should completely diagnose and fix, no cost to you. If they can't, then a lemon law should come into play.
The car is design for plain ol 87 oct gas. No need for anything else. There could be a gas delivery problem in your area but I doubt it... just them trying to get you off their case. Stick to it.
In the end though... try not to worry about the noise... simply press on the gas pedal to make it stop.