Rough engine start

Hi Charlene -

When they tried to duplicate the problem, do you know if they had let it sit out overnight in the cold? If not, that might explain their inabilitly to duplicate it. Perhaps they could be persuaded to try again.

I also think the Corolla they gave you should have been considered a *loaner* and not a rental, and they should never have charged you for such a thing. Their statement that they deigned not to charge you for the diagnostic work (c'mon, what is a warranty for?) sounds like they were blowing smoke in hopes that you would feel that they 'let you off easy,' so to speak. You'd think they would want to please the customer at a time like this, when they are experiencing such bad publicity, but I guess the dealership's perspective may be different from that of Toyota Corporate. Perhaps consider calling Toyota's Customer Experience Center at 800-331-4331. (This might be a mid-atlantic number only, but they should be able to give you one for your area.) Also consider switching dealerships (or telling them that you are considering doing so), if there are others nearby. Good luck!

~Tim

 

I am a late comer to this thread, after all it is in the Gen III forums
and I'm one of the hold-outs who still drives an '08 Gen II. :wave:

I had a single rough start event some weeks ago, earlier in the winter;
violent shaking and loud knocking sounds. It scared the bejezus out of
me and I immediately shut everything down. I sat for a few moments
completely befuddled by what had happened. I decided to restart, but
before I did so, I depressed the go-pedal to the floor a few times.
Why? I don't know, old habits die hard, and I was thinking of a stuck
throttle linkage or choke... nah!

On restart the condition was still there, but greatly reduced. After less
than 400 yds at ~20 MPH it was gone, and has not reoccured.

The car is parked outside. I rarely have cause to move it after parking
for the night. I don't know but I could have done so the night before.
My driveway is only about 25 ft. long, and if I were going to back and
then forward, I would use my EV switch to surpresss ICE start up.
Then too, if air temps were below 32 degF, EV mode would be
unavailable.

No oil change or car washing involved. Car does sit at a slight nose
down attitude.

As to the cause, I'd like to suggest that it has to do with conditions in
the exhaust/catalytic converter pipeline. I think that the short engine
run times that have been reported to precede these incidents leaves a
high HC content gas mixture in the system... remember, the HSD runs
the engine very rich in the minutes after start up to bring the CC up to
temps (I've been told. :noidea: ) What with subsequent low temps, the
HCs might even condense. At any rate, when the ICE is restarted, I
would think there is way too much HCs in there and for sure the
sensors are going to tell whatever computer/ICU is in charge that
things aren't right. In turn the air fuel mixtures in the intake would be
fiddled, and as the condensed HC reflash to vapor, things would be a
control/feed back loop nightmare for a short pertod of time.

Completing this scenario is wholly outside my technical understanding.
Some inkling of the interplay of the sensors in the exhaust/CC chain in
the Gen II can be gotten here. But I can't quite understand it all.
I know the Gen III is somewhat different.

That's my best pseudo-SWAG. (Scientific Wild-nice person Guess)

 

Hi Tim,

Yes, they did leave it out in the cold. They had it for a few days, and tried it more than once. The thing they did not do was start it and turn it off in under a minute, and then start it up the next day. This is what I had done the day before it happened.

I am not happy about being charged for the rental, but I did pay it.

Charlene

P.S. It hasn't happen again since I got my car back almost a week ago. It has been running really well, but I haven't repeated the short start scenario either.

 

I like your theory. Perhaps an additional factor is the cold startup viscosity of the oil which is used to control the variable valve timing. It is a fact that both the Toyota 0W-20 oil and the Honda 0W-20 oil are similar to each other and unique among 0W-20 oils in that the both have an unusual high viscosity index. Both of them have a VI of over 200+ while no other 0W-20 that I've seen a measurement for is greater than 175 (see here). The other notable difference in the Toyota and Honda oils is an astoundingly high molybdenum content.

The higher the viscosity index the less the viscosity of a fluid varying with temperature. So a 0W-20 with a high VI will potentially be less viscous than one with a lower VI. Perhaps the higher cold start viscosity of non-Toyota non-Honda oils is operating the oil driven variable valve sprockets in such a manner as to contribute to the rough engine start?

Has anyone had a rough engine start while operating with either Toyota or Honda 0W-20 oil? I for one have not experienced a rough start on my Prius and am now on a fill of Honda 0W-20 after a drain at 2,100 miles of the factory oil (car has 3,200 miles total).

Rumple

 

I have had the rough start a number of times over the winter. I'm at 11K and had my oil changed at the dealership at 5K. It started happening to me when the temp dropped below 40 but does not every morning. It does seem to happen more frequently when the temperature is colder out. I've had it happen once or twice a week since December. Only occurs for about 3-6 seconds and then it levels out but sounds like the engine is going to explode or fall out of the car.

I just took it into the shop for the ABS and they said they couldn't duplicate it. I told them they didn't read what I told them because it only seems to happen on that first start in a cold morning. They didn't even want to hold it overnight to test.

 

Other people have reported having a rough start if the engine had run for a short time previously. Maybe you could try an experiment: Run the ICE for only a few seconds and then shut it off. Wait for some time and then start the car again to see if you get the rough start. If so then you can demonstrate it to the dealer. Good luck!

 

I have also had this problem. To those of you reading who haven't experienced it, it was so bad that myself and two passengers thought I should turn the car off rather quickly. I can only imagine that this is how an engine would run without any oil... I did manage to look under the hood one time and the whole engine was shaking violently. It has only happened twice. I contacted a Toyota tech and explained the problem as best I could but I'm not sure he understood what I was talking about, since anyone would clearly understand that this type of engine behavior is not within normal operating tolerances, i.e. you can't ever visual this happening unless something is very obviously wrong. Here is the response I received from the Toyota tech (English isn't too hot, I think the tech is Japanese based on his name which I have omitted):

Thank you for using our “Ask a Tech†forum.
There is a heavy rotor inside of the Trans axle assembly, which works like the starter motor and electric generator to crank the engine when needed and charging the main battery, is designed to rotating in forward and/or backward with a variable speed to give the vehicle constantly changing transmission gear ratio including obtaining the reverse gear. Therefore, some guest might feel some sensation when this heavy mass changing a direction and/or start cranking the engine to start.
I would recommend that you bring your vehicle into a Toyota Dealer to compare your vehicle to other similar vehicles to see the difference.

 

Do you know if the dealer used Toyota 0W-20 oil for sure? Many dealers do not do so - there are several complaints on these forums of dealers even putting in non-recommended grades of oil (e.g. 5W-20).

Rumple

 

What is so odd about this is that some cars do not experience it. Our Prius has never had a rough start and the temperatures in NJ this winter have been from mild to cold (e.g. 10F) and not once has the car exhibited this behavior. Has anyone had success in duplicating the issue?

Rumple

 

YES! My experience was just as you say. I too felt the engine was shaking violently.

I did not look at the engine while it was doing so though. Was it the ICE that was shaking or the MG's? My impression was that of the shaking coming from direclty in front of me....where the MG's are. I am very curious about this.

I was afraid to drive my car for fear that I would permantely hurt it.

It has not happened to my car again.

I do not feel the tech's explanation is correct. He does not seem to understand the severity of the problem.

 

Whenever you've made a complaint, they will tell you they've never heard of it. Thats what they said when I told them about my brake issue.

 

That seems to be Toyota's answer to every problem, "oh my, we have never heard of that before".

If they are truly interested in improving the company that would be a very good place to start.

 

I took my car in for its first oil change on 2/26/2010. After discussion with the Service Director, he told me they have had 1-2 other customers expressing the same concern about hard knocking and shaking.

They sent my request to the NW district rep and after an initial review they are leaning towards the problem having to do with the engine mounts. They also confirmed they are only seeing reports out of the colder weather states. Temperature seems to be a contributing factor.

I am in the service directors file to be notified as soon as they have a technical solution. I'll keep you posted.

 

Thank you, that's progress. I'm glad they are finally listening to us about this.

 

Thank you! I am looking forward to further updates.

 

I haven't been reading the thread, but just saw the video. That sounds Horrible! I query whether 'just' engine mounts could do that? Doesn't some of it seem internal to the engine??

 

A few thoughts - I don't want to hurt any feelings here but... I think some of your assumptions are backwards - at least with respect to basic engineering principles.

(1) Temperature effects on spring constant of steel is probably negligible (not zero, but it's probably hard to peg without knowing the actual steel composition).

(2) Older oil usually gets thinner - as viscosity enhancers break down, and it is diluted by combustion by-products.

(3) In colder temperatures you should use lower viscosity oil, NOT higher viscosity oil. The reason is that oil doesn't flow so well when its very cold, so you compensate slightly for colder temperatures by switching to lower viscosity oil....

Sorry to be the bearer of contradictory news (I see from above there are already some sensitivity issues at play here)...

 

Ouch! That sounds awful, like a part is really loose, or there's no oil in the engine. Good luck and keep us posted!

I just remembered an issue with my 02 Sienna: sometimes it would run rough if, on its previous start, I shut the engine off before it warmed up much. For instance, starting up on a cold morning and driving just down the road to get coffee; upon second start at coffee shop, it would sometimes run rough. Any similarity.

 

This has happened to me several times and the sound reminds me of exhaust pipes rattling, maybe not, but if it were a motor mount problem that could be what I hear?

I also have a possible work around that might or might not work. But I was hoping someone else would try it and let me know if it works for them.

I haven't had a rough start for about 2 months now. What I have been doing is putting my foot clear to the floor to start the car as soon as the "ready" light comes on, instead of waiting for the 12-15 seconds to pass and letting it start itself. As soon as the engine starts I let off the throttle.

It might work, might also be just a coincidence. I decided to try it because when I had my last rough start incident instead of turning the car off I pushed the throttle to the floor for a second or so to see what would happen and it smoothed right out.

 

Thanks for posting the video, very interesting.

I agree.

My guess is that the problem is with the variable intake timing (which is controlled by a hydraulic device within the intake camshaft sprocket that uses engine oil, under engine ECU control), and that if the timing is too retarded then that unusual vibration will occur. By depressing the accelerator, that causes the timing to change which makes the engine run more smoothly.

Maybe the root cause is that oil drains out of the hydraulic device under cold weather conditions and it takes several seconds for proper operation to be restored.