1.8L starting rattle, knock, events

Both times this has happened to me it was the same as you state, I moved the car a short distance from the driveway to the garage and shut the car down before it completed its warmup cycle. It was cold the next morning when I started it.

I remember seeing a discussion thread some time ago where it was explained that it may possibly be due to what was called "cogging" of MG1. When the ICE shuts down normally, MG1 stops in its optimum position for restart. When the ICE is shut down before it completes its warmup cycle and the ICE gets cold-soaked during the night, this can create this cogging issue. Hopefully some of the experts can explain this better than what I remember.

Once I read about the cogging issue, I learned when I am moving it a short distance to use EV mode if available or let the ICE complete it's warmup cycle. I have not had the knocking issue since.

If it were to happen again, if you floor the accelerator the knocking will stop.

 

From what I've heard so far, that may not be possible. You might want to also just concentrate on what happens differently when the engine is started when the previous start ended with the engine fully warmed versus ending after only running the engine briefly. Even if you can't reproduce it, finding how the engine behaves differently between these two conditions might lead to some theories. If the spark advance differs based on whether the engine was warmed up last time it ran or not, then that's very likely something in the chain of events that leads to the engine knock, and there's some other condition that causes it to be sporadic.

If it doesn't differ, then you'd really need to reproduce it at will to be able to prove that it *wasn't* the spark advance causing the problem, and the sporadic condition is causing the spark advance to be different from a normal start.

 

I have a 2010 with 26,000 miles on it. The first time I heard the knock was at 7,000 miles. It was about 20 degrees farenheight outside and I was starting it for the first time in the morning. I just heard it again at about 24,000 miles and about 35 degrees. Both times it was about the same noise. It sounded like a hammer was banging all around under my hood. Both times made me fear damage was being done. Both times I had it checked out and there was no problem found. I live in North East Ohio.....

 

Well, my wife got the noise in her car this evening, wish I had heard it but she said it lasted 30-60 seconds before it stopped.

What I do know is this:

We started her car about 4pm, backed it out of the garage into the street, pulled it down the road 20 feet then backed it into the driveway and shut it off, about 30 seconds of running. Meanwhile we unloaded a ton of wood pellets into our garage, maybe 15-25 minutes total. I moved my dads truck, moved my wifes Prius in front of her garage door, about 30 seconds of running and shut it off.

About 7:15 she left to go grocery shopping and got the noise.

Temps about 28*F, roughly 22K miles on the her (the car not my wife!).

Thats about as detailed as I can get, I hope it helps. We will report it to the dealer so we have record of it.

 

I do not have a hammering noise but it is rough when it starts sometimes. But I notice this is only in reverse. When I put it in reverse, cold, it starts out on battery but after a few seconds the gas engine starts up and you hear it. If you start in forward it is always very smooth.

Do other hear this in both directions or is it always in reverse?

TED

 

Appears to be a definite pattern here: This event is rare and occurs only on a totally cold engine that, prior to last shut-down, had run for a very short time that run also occurring when the engine was cold.

A lot of people are now saying that similar events came before their knocking. I'm comfortable with saying that it's highly related to this behavior, though the one time I deliberately tried to cause this to happen it didn't. I think that's just due to its rareness, not that the issue is not still related to a cold start after a previous very short run.

 

I had just about the same thing happen I have owned the car since August 2010 it has a little over 2,000 thats two thousand miles on it and the temperature just was in the high 30's to the low 40's overnight.

Saturday moved the car to wash it several hours later moved it again to put up Christmas lights. Parked it with ICE engaged.

Car often engages ICE in fact I always allow it to do so before allowing the car to move to prevent changes in acceleration.

Monday Morning 6:30 AM go to start car as usual wait for the ICE to kick in makes a terrible noise with all kinds of vibrating shaking under the hood ICE smooths out after a couple of seconds I drove it to work this morning.

I do not remember ever reading anything in the owners manual about letting the ICE complete it's cycle before shutting off the car, in fact I never have and I have shut it off many times before while the ICE was running.

By the way is it common or normal to have a ratcheting click in the steering column when straightening out from a parked position? Nothing serious sounding and it only happens when pulling out after starting but it does happen overtime without exception. It sounds like something is calibrating.

 

Somebody who's better at math than I could tabulate the findings here. I think we're all saying the same thing, the conditions are quite predictable it's unfortunate none of us have yet been able to reproduce this on demand, though.

 

As Ted asked, it would be interesting to know whether people who experienced it where on Reverse either when they pressed the Power button to shut it down or when the engine started.

I'm asking this because I think I experienced a short rough start once in the first few thousand miles of my Prius after backing up for a short stop (in cold weather). This was 10 months ago so I'm not 100% sure whether I was backing up when the rough start occured or if I had shut it down in Reverse...

PS: I'm not sure we can really find a meaningful/relevant pattern though, because most people park one way and leave the parking the same way (thus reversing before or after), the only hope would be to detect whether reversing before or after has an impact on the probability of having the problem.

 

Now that the question has been asked, I always back my car in to the carport. So, the car was last in reverse before putting it in park and then shutting it down before the engine completed its warmup cycle.

It was in P when started and while knocking took place.

 

We always pull into driveway in D, so no chance in the world it was in R during the pre-knock shutdown. Whether it was in R during the knocking sessions (i.e. car powers on and then before ICE turns on it's put into R) or not I cannot say but I'm highly suspect that gear has anything to do with it given that the car is totally unmoving when this happens.

 

It happens the same to me and only when coming out from parking. I don't think it is a malfunction - it would be really interesting to know what exactly it is...

[Separate thread about it from 2010priusowner here]

 

Happened to me this morning. parked last night in stage 3, reversed onto drive, and then pulled forward about three feet, it was about 0C. this morning it was -8C, started the car, loud and unpleasant knocking, floored the throttle, it went away, let off and the sound returned, but much much quieter. car drove normally after warmup.

It sounded like a really old cantankerous diesel.

 

It sounds like when you parked last night the ICE was at full operating temperature? Or, was it just that you moved it a few feet and during that move it had been sitting and was cold, so you moved it cold and then when it turned off it was still cold?

 

I got a theory but i know nothing about how a Prius starts?

My theory is that they start differently in reverse. Most cars start with a starter motor but I think the Prius starts with the electric drive motor when going forward. I don't think this can happen in reverse so it may have a separate starter motor when in reverse; more like a conventional starter motor?

So when they start in forward it is perfectly smooth, but in reverse it starts differently, more like a conventional car, and this is why we feel the difference.

Anybody has knowledge that will blow my theory out of the water?

I went to buy a service manual because I like to know how my cars work and I like to work on them. The problem is that they cost $900 and this is stupid expensive. I did find a CD on eBay that is suppose to be a copy for $10. I did buy it because it was very cheap but have not received it yet. I will buy the real book in a couple of years when I can find a good use one for cheaper.

TED

 

When reciprocating aircraft engines do this, it often indicates a sticking valve(s).

Don't think it's carbon, which would cause preignition. Don't think it's detonation either (which usually results under heavy load with high combustion chamber temperatures). A cold engine won't lead to either of these.

My bet is, either that something's up with the valvetrain, or possibly a fuel metering issue. But the banging noise as some have described seems like a clue, and could be caused by improper ignition timing, especially if it's advanced too far.

 

Bob Wilson et al.:

This is not engine knock. It's valve-train noise.

Engine knock sounds like a loud hammer and indicates severe engine problems. What is in the video is not engine knock.

Engine ping sounds like firecrackers inside your engine and occasional ping is typical with Toyota engines, as they run near the borderline compression ratios and air - fuel mixtures for best thermodynamic efficiency.

This is valve-train noise. Occasional valve-train noise, especially in cold weather or during engine start-up, is nothing to be worried about. If it happens consistently, if your engine sounds like a loud clock or sewing machine all the time (when it's warm), you need to have your automatic valve-clearance adjusters, called valve-lash adjusters, replaced.

Ignition timing will increase with engine RPM. So, what you're seeing is normal. When the RPM decreases, timing decreases. The reason you're seeing small ignition timing at low coolant temperatures is probably because of emission regulations. When the coolant temperature increases, EGR kicks in around 50 Celsius (120 F) and then the ignition timing can be increased without increasing the NOx emissions.

Also note that knock would happen at higher (more advanced) ignition timing, not at lower (retarded) timing. Also, as mentioned above, a cold engine is much less likely to knock. Knock is something caused by excessive temperatures in the combustion chamber (due to overheating engine, too high compression ratio, overadvanced timing, insufficient EGR cooling, glowing carbon deposits, too much air in the [too lean] air - fuel mixture, etc.) and/or low-octane gasoline.

Also, always use the appropriate grade and quality of motor oil and have it changed at a trustworthy mechanic (or do it yourself). Always check your oil level and never run out of oil. Never race a cold engine and always drive smoothly, especially with a cold engine. These simple things will minimize any problems with your valve train or the rest of your engine.

Again, relax, this is not engine knock, and it's nothing to be worried about. Engines can have unusual transient behavior in cold operation.

 

Woah, just watched/listened to the video. Valvetrain. Definitely.

That doesn't sound good to me.

Normal valvetrain clatter goes away in a few seconds or less, once the oil reaches the top of the engine and the hydraulic lifters pump up (if so equipped, I don't know if the 1.8 has roller cam followers). This is not normal valvetrain clatter. It takes too long to go away and actually comes back—worse—after ten seconds or so before disappearing.

Where does the 'oil' light pressure sensor take its reading from? What is the oil pressure doing when the engine starts up? That's what's missing from that graph. I find myself wondering if there's an internal oil leak somewhere in the engine, preventing oil from getting to the top of the engine quickly, and in sufficient volume. But that probably wouldn't be intermittent.

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Another thought: Does the 1.8 have variable valve timing? If so, the noise could be caused by that. What actuates it? Electricity? Oil pressure? In that case it's either a software malfunction, some sort of solenoid issue or—once again—an oil pressure problem.

My best guess: there is indeed variable valve timing on the 1.8 and it's oil pressure controlled, and something is causing it to misbehave.

I'd say it's not normal. I mean, have any other new cars you've ever bought prompted you to point a video camera at the engine bay?