Rough engine start

Wow this appears to be a very widespread problem. My Gen 1 did this to me for about 10 seconds when I went shopping with my wife. Then a few times later after that. It was so violent, I thought somebody hit me the first time it happened. I added some "Wynn's Tune Up in a Can" because it exhibited sticky valve syndrome, and all these years later it never happened again. Just a thought, and it won't void your warranty.

I have said it before, the 1.8L is a terrible engine for Toyota, and I have no idea why the blazes Toyota used it in this car. Its such a noisy and unrefined engine, and the primary reason I sold my Corolla LE in the first place. 1.8L are known for suffering from heavy oil consumption and sticky valves, warped heads. My Corolla had a collapsed valve spring on number 4 cylinder on the Intake side, and the car was virtually undriveable. Incredible considering the red line on my Corolla was a laughable 5500 rpm! The 1.5L is a much better design. Toyota has such an excellent 2.0L in Europe and Japan in the Avensis, it would have been so much better.

 

Has it happened to anyone "before" you did your first oil change?

 

It happened to me just before my first 5K oil change. Short trip from driveway to garage in cold weather. I have since intentionally let the engine continue to run on short trips just to make sure engine goes through warmup cycle before shutting off engine. I have not had any issue since.

 

So you saying the 1.8 in the prius is the same exact engine 1.8 you had in your Corolla?

 

Twice before, but it settled down quickly

 

I almost did not feel the need to respond to this, but I will defend my honour! LOL! Just joking! Obviously they are not the same engines! Not at all, but the fundamental architecture of the motors is quite similar. Its a lousy engine in the Corolla, I only hope the Prius running on Atikinson cycle proves me wrong. I don't know, only time will tell.

 

If it was a 2008 or 2009 Corolla it could have been a 2ZR-FE, sister to the 2ZR-FXE in the 2010 Prius. Earlier model years had the 1ZZ-FE engine.

Given that mlibanio joined PriusChat in 2008 and his first post was about the Prius, I think it's unlikely. In a previous post he mentioned a 1999 Corolla, which would be the ZZ engine; at the time it didn't yet have VVT-i, which was added for 2000. (Source: http://en.wikipedia.org/wiki/Toyota_Corolla_(E110))

Looking at the model codes, the 2.0L Avensis had a 1AZ-FSE prior to 2009, and 3ZR-FE afterward. In Europe it has the Valvematic 3ZR-FAE variant. The 3ZRs share a lot of design features with the 2ZRs.

Explaining the engine model codes: the first digit is the block variant within a family (numbered sequentially where 1 is the first variant, 2 the second - capacity is unrelated so a 4 might be smaller than a 2 depending on what was needed first), then the letter or two letters before the hyphen indicate the family. The letters after the hyphen indicate specific features. F and E indicate "Economy narrow-angle valve DOHC" and "Electronic Fuel Injection" respectively; most mass-market cars will use an 'F' variant and all will have an 'E'. The FSE indicates direct injection, A indicates Valvematic and X indicates Atkinson-cycle.

 

Spot On Mike! At any rate, I am simply trying to point out the symptoms posted by everyone here, are not uncommon to symptoms related by fellow Corolla owners from 1998 until now. It seems regardles of whatever application, something about these 1.8L engines seem to have a fundamental flaw about them. Not being a G3 owner, I am merely contributing to fellow Prius owners my experience and knowledge, and as a mechanic, which may help to determine the cause by demonstrating commonality of issues. Perhaps in the future, I will simply stick to the G1 forum and that will be that. I was simply trying to be helpful. In all other car clubs I am affiliated with, this is how we tend to find the cause of all our problems, through open discussion.

 

Has not happened to me. Just changed my oil today for the 1st oil change at 2,200 miles. I do not see why an oil change would make conditions for a rough start, but no doubt that's a limitation in my powers of reason! Will report if this ever does happen on our Prius.

FWIW: after settling a few hours, the oil is about 2mm-3mm below the upper dipstick dimple.

Rumple

 

In my case I ran the car for about 45 seconds to get it up the ramps for the oil change, but I don't recall the ICE kicking in. Then, hours later with the change complete, I ran for another 45 seconds or so to come down off the ramps and let the ICE run for a bit.

So perhaps vehicle inclination could be a factor.

So that makes 3 potential triggers for this issue: (1) temps around freezing, (2) short previous run time, (3) inclination.

 

Please stick around. So you're saying this might be a sticky valves issue ?

 

:welcome:
Actually we need and appreciate all the help and ideas we can get. I think we should all post anywhere we wish and keep trying to help each other. Please keep posting on this topic with anything you think might be of use, and thank you.

 

Hi Guys, thanks for the support, its very appreciated. Indeed, because of the ultra-lightweight valve and valve spring design of this version of the Prius engine, I suspect that they become stiffer as a result of the cold, and perhaps take a while to "free up" or "loosen up" a bit. The fact that this issue is also directly after an oil change is also indicative of this. Older oil is thick and tends to stick to parts more readily than fresh oil. Further, the 0W20 oil the Prius uses may not be suitable in such frigid temperature. I have used 0W30 in my Prius for quite some time, and no issues. But in winter I use 5W30, which I just find helps the motor run smoother in super cool temperatures.

Any thoughts?

 

Seems I recall an issue I read some months back that depicted problems when not allowing the car to warm up.....

However.. the viscosity of the oil is easily misunderstood.

The colder it gets, the thicker oil gets and the hotter it gets the thinner.

So to say you use thicker oil because its colder is reverse rational as to how viscosity is normally chosen.

As the temp gets hotter and things get thinner, the thicker higher viscosity oils fare better and as it gets colder and things get thicker and gum up, the thinner oils excel.

I can't imagine this is a viscosity issue at all unless the engine has some serious build problems. This engine has been proven in many Toyota cars.

I can see a vapor lock type scenario since the ethanol gas combined with the complicated computer handling of vapor/fuel ratios etc. are quite complex to control in all temp/humidity circumstances.

 

Had another occurrence this morning, first time in at least two months. Mileage 12,000, temperature 40 degrees, car had been setting outside all night, overnight temperature was only down to about 32 degrees. Last oil change was a month and a half ago, using Mobil 1 0W20.

I started it last night to check something on the ScanGauge, it ran for about 15 or 20 seconds then I shut it down for the night. Went out this morning and it started to vibrate and bang as soon as I started it. I immediately shoved the throttle to the floor and it smoothed right out so it only went on for about two seconds. Pushing the throttle down all the way seems to stop it, in my car at least. I stopped it that way one other time also.

 

Humm.... almost sounds like an air bubble in the fuel line

interesting..... nice to know a workaround......

 

My previous car (w/ Mitsubishi 3.0L V6) had a well known hydraulic valve related "tick" issue, often more apparent after an oil change and with specific brands/viscosities. But at worse the engine sounded like a sewing machine; there was no violent knocking.

If this was the cause I'd expect the problem to recur more often, but who knows ?

I used Mobil 1 5W20 for my first oil change after which I experienced this problem.

 

Well I must add this to the occurence list...

Had it happen this morning, "First TIme" since taking delivery in August. About 34 Degrees, car garaged all night, lasted only 4-5 seconds tops.

Actually started the car and got out of it and when the ICE started it sounded like someone was slapping a Rubber Tire on the fender..but it smoothed right out after 4-5 seconds as mentioned.

I was close enough and did not feel the car shaking....as I was trying to jump in fast to shut off, but by the time I opened door it stopped and smoothed out.

Not further occurence of it today, car running normal. 3560 Miles, have not changed oil yet. Oil Level appears to be in normal range.

 

Still think it is an over rich condition, basically flooded. Why I don't know, maybe it has something to do with the vapor recovery system. Is the vapor recovery system purged right after start up? I think it is, so if you shut it down in the middle of a purge, it's a little rich, then you restart it in the morning and it purges again and get's real rich?
Opening the throttle of course adds air and would lean the mixture. How do you start a flooded engine? Open the throttle of course. Makes sense that opening the throttle would stop it if it's due to being too rich. Of course this thing is drive by wire, pressing the throttle does not open the throttle, it asks the computer to open the throttle, but I assume it does as requested.
If the rough start is a result of a rich mixture, then no damage is occurring if it is a rare thing, but it is I'm sure obnoxious.
I'd bet lunch that it is NOT valve train related

 

Thats the same complaint my wife has every time I eat food thats too rich!...