Prius III engine knocking at high torque low RPM (solved)

Daspi - I read one of your earlier posts that your mechanic manipulated the EGR open and closed. Do you know how or where to manipulate the EGR? I havent looked at my car yet to try to locate the valve but an idea of where it is would be nice!

You can refer to the drawing in a post above!

Thanks!

 

@RyanFlorida: He just plugged it in the service port and manipulated with the snapon computer thing. Electronically stepping it up to full open and close again a few times.

 

Just got a Warranty Enhancement Notification - ZF3 addressing and acknowledging the rough idle issue with or without P0401. Seems I was not the only one suffering with a stuck EGR. Glad Toyota finally acting on it. We will see what the dealer will say now that the code is gone and the EGR is NOT currently stuck. Maybe a link to this thread will convince them to replace my questionable valve.

 

Did your mechanic put an egr block off plate? Is your car running well with no cel?

 

I think he manipulated the valve using the Techstream diagnostic computer, and not by physically touching the EGR.
But if you look at your engine, there's a plastic silver piece that covers the oil fill cap. The EGR is below the right side of that plastic cover, as you face it (driver's side). The plastic cover lifts straight straight up and comes off without tools; you won't break it.

There are three parts to the EGR: The EGR cooler, which is on top of the EGR. This has two small cooking hoses attached to it. The EGR is beneath the cooler. Then, there is a small metal pipe which runs from the EGR to the intake manifold.

If you want to get started at looking into this, go to the sticky posts and review the NutzAboutBolts video for EGR pipe cleaning. That's the first thing to do, because if your EGR pipe is clogging, it's a sign that you might want to remove and fully clean the EGR itself, which is more painful.

The EGR is indeed a valve, and if it sticks open or closed, you could have difficulties. One poster said that manipulating the valve was enough to free it up, others have disassembled the whole thing and cleaned it up to remove the carbon deposits and make it work like new.

 

I have an exchanger that is completely blocked that is waiting for a long soak in Purple Power. It'll be interesting to see how long that process takes as it's that blocked that neither light or liquid can pass through it.

 

I have some similar problem,
When the engine is under low load or coasting speed it is vibrating. When i hit the gas its gone. When i loose the gas its gone to.
I'm thinking a gummed egr.
I took the egr pipe of to see how bad it is.
Do you think the gummed up egr can cause the engine vibrating under light load?
The black substance was hard and not oily

 

I wanna report back, the vibration is gone. I cleaned the EGR and intake.
The small channels where full of junk.
So if your car is vibrating at coasting? Clean the egr and inlet

 

Hi guys!
I am not very technical is these aspects however I got my EGR pipe and intake manifold cleaned by a certified mechanic(who I should mention was not aware of this problem and had to be shown the prcoess via the pictures and guidance you guys posted) but my problem has still not gone away. My Prius has started knocking more than before. I am uploading the pictures of the things I got cleaned from the mechanic so someone might suggest anything I missed.
Kindly guide!

 

How many miles on your Prius? Owned since new? Did the mechanic clean the small passages in the intake manifold where the egr returns? How much carbon deposits did he find?

 

Thanks for your quick response!
The images I uploaded are all the gadgets the mechanic cleaned up. There was not a lot of carbon as seen in other pics in the thread. My car has been driven 150,000 kms. I am the second owner. I got it three years ago when the mileage was 72,000 kms.

 

What I'm asking is do you know I he cleaned the small inlet passages from the egr system into the intake manifold? If not, cleaning the egr system will only be so effective.

150 k km's is about 90 k miles. Have you tried anything else to combat the knock? Are there any dash lights on?

 

Here in the US Toyota started replacing the EGR valve on cars with those symptoms. I had mine replaced and the CEL came back on a few months later. I noticed that Toyota replaced only the valve and not the cooler which would more than likely be clogged as well. Car started to knock and had a misfire # 2 code. My mechanic checked every thing and determined the system is clogged again causing this. They will be replacing the cooler, as cleaning it is too much labor. I will contact Toyota and mention the failure not sure if they will do anything though. Any one else have the EGR service completed to have the issue return?

 

If the cooler is clogged you can bet there's likely a ton of junk in the EGR pipe going back to the exhaust. I replaced my EGR and cooler, cleaned the EGR pipe that goes from the EGR to the manifold and got a newer intake manifold that was cleaned spotlessly. Everything was great for about 600 miles (or almost two weeks for me) and then it all went downhill from there. The junk is back. I haven't had the cooler off yet but there's already enough crud in the EGR (had the cap off) and in the pipe and manifold to guess the cooler is gunked to the max.

I guess this means I'm getting all of that stuff off the car again and likely the exhaust manifold. All of the above will be cleaned with something super caustic, like Nancy Pelosi's makeup remover or something similar.

 

That sounds really really bad. You're getting a LOT of oil and grime coming out of the exhaust. Are you getting blue smoke out of the exhaust?

 

Well at 214K miles the mechanic revised the problem... Blown head gasket. Since it was burning a quart of oil every 1000 miles for that past 120K miles they are going to swap the engine for around $5000, if they can get a under 50K and 1 year warranty. They seem confident they can find the engine. That seems like a reasonable investment to make, I will then try to take this car over the 300K mark.

 

That is an awful lot of money. I'd expect closer to $3k. Also check out danlatu's stickied thread. The service manual's directions include dropping the engine through the bottom. It's possible, easier, and quicker to pull through the top.

 

OMG!
Just did the job again, i felt the same vibration again. There was 1 little peace of gunk again in one of the inlet channels and it block it again. Must be a left over. Now cleaned it very very good. And of couse once the litle peace was out of the small EGR channels engine runs smooth as butter again

 

What is that, a little blob of plastic left over from moulding process?

 

No it was a peace of carbon deposits.