First start-up on a cold(ish) morning...

<div class='quotetop'>QUOTE(TheOtherGoose @ Oct 28 2007, 09:20 AM) [snapback]531545[/snapback]</div>

Do you have an engine block heater installed and in use? This summer I found that using the engine block heater results in a 'knock' for the first 1-2 seconds when the ICE actually starts burning fuel. The initial 'spin up' doesn't have this knock. But so far, I've not been able to isolate the source.

How long ago was your last engine oil change and what did you use?

Thanks,
Bob Wilson

 

Mine has never made such a noise, even at -40 parked outside at my hobby farm. Get it checked

 

Start by checking the oil level.

 

The engine on the Prius does sound a little like a diesel. The Atkinson cycle makes it clatter a bit more than normal, and the engine soundproofing is lighter than on many cars. That's probably what you are hearing, but if you have any doubt, have someone with Prius experience listen to it.

Tom

 

<div class='quotetop'>QUOTE(TheOtherGoose @ Oct 28 2007, 02:35 PM) [snapback]531623[/snapback]</div>

Oh lordy put some decent oil in that high tech car of yours. If your dealer is like mine they will put the sh*ttiest oil in it they can. Not to break your chops but if your quoting "Atkinson-Cycle" and then guessing what kind of oil is in your car your making so little sense you makin' my head hurt. Run..don't walk and put some Mobil 1 10-30 in your car and then buy a EBH from PriusChat.com.Thank you. That is all.

 

<div class='quotetop'>QUOTE(TheOtherGoose @ Oct 28 2007, 11:35 AM) [snapback]531623[/snapback]</div>

What octane fuel are you using? Also, try another station. You might have contaminated gas, it sounds like a knock to me. (pinging)

 

My Prius hasn't done it yet, but my 05 Corolla S two or so times in teh winter had a noisy start. As has my wifes 98 Stratus. Just once in a while, things sound much more noisy than normal. Always scares the crap out of me, probably happened less than ten times over the past ten years, but I consider the rare noisy startup normal.

Oh, always used M1 oil, usually use PureOne or Wix Gold filters.

There is something called an anti drain back valve in oil filters that helps keep oil in channels ready to lube stuff as soon as the engine starts turning over (rather than having to be pumped back up from the pan). I suspect that our oil filters are using this method, and once every blue moon the valve doesn't seat entirely and the engine clanks until oil smothers everything again. Just a uneducated guess.

 

This just happened to me today. Had not started it in 3 days, but it was 73 degrees outside and it was shuddering and knocking so bad, I turned it off. Just had an oil change 250 miles ago. 90K on the car. This has never happened before. Thoughts?

 

Did you move the car in the driveway (i.e. very short engine-on time), then let it sit overnight, and then experience the shaking the next time you started the car? If so then this is consistent with what many others have reported.

Rough engine start | PriusChat

 

Check the engine oil level on the dipstick.

 

Yes. That's exactly what happened. It was moved from across the street. Thank you.

 

OK that's probably the same phenomenon reported by many in this thread
Rough engine start | PriusChat
and there is nothing we can do about it.

But just in case it is still a good practice to check the oil level as Patrick suggested.

 

...this is where the retrofit EV button would be nice to allow moving vehicle without ICE

 

Absolutely true. This where I often use my EV button.

Interesting thread 2009. Apparently it's something that can happen to various modern cars when the engine is cold started and run for only a very short time. My brother once did this in his 2006 Mitsubishi colt. He moved it just a few meters to get his other car out, and then went to start it a few days later and it coughed and spluttered and wouldn't even start! After several attempts he called a mechanic for roadside assistance. After giving the mechanic the back story he then started it immediately just by cranking with full accelerator pedal (which of course is something you'd never normally do in a modern fuel injected car). Apparently he said it's fairly common problem and is similar to "flooding" in an old carburetor engine.

Personally on the Prius I make a habit of allowing the ICE to complete it's warm up cycle and cut out before shutting off in the case where I accidentally let the engine start when just moving the car a few meters (I say *accidentally* because it's only if I forget to use the EV button). I've never really thought too hard about why I do this, but I guess it's a good way of avoiding this problem.

Agreed +1. With any engine problem happening soon after an oil change it is worth doing this. Actually let me rephrase that: Problem or no problem, always check the oil level *yourself* after anyone changes your oil.