Rattling/vibrating at low throttle

IMHO, cleaning EGR pipe and valve may not be enough. You need to clean intake and maybe even EGR cooler.

 

Welcome to Prius Chat .

+1.

Sounds like you are the DIY type. The intake manifold is a 1.5 hour job. What did you see when you cleaned the egr pipe?

How much oil is the car consuming and disna light on the dash let you know the level got low?

Keep us posted

 

If you can wait until Sunday I'll have both of them ready. @m.wynn and I will give it our best effort anyway as Saturday is when there is an Upstate NY meetup.

I have done both myself. They are not hard, but the egr cooler is best done when the windshield wiper cowling is removed. It is also a bit fiddly.

I'll try to give you a good tutorial .

 

It may be not suitable for small children, but we will have some sort of documentation detailing an entire EGR circuit cleaning. The spanners will be flying in the WynnStar (Star is my wife's name) team garage Saturday morning.

mattcav30, did Toyota really give you an EGR valve with no CEL and P0401?.. One less part of the circuit for you to have to clean yourself, anyway. It's an odd thing they've done with that TSB, throwing a part at a code in what amounts to nothing but a stereotypical "parts changer" move, leaving the actual problem completely unattended to. Then waffling about a possible blockage in the intake manifold... At least the factory trained techs have a hunch that your intake manifold, EGR circuit is packed full of black sludge. The cam gear and coupler nonsense is solid gold, though. This is how you build a multi-billion dollar corporate empire, peeps. Good intuition by you to not let them have at it. It seems the only way it will be done right is to DIY or explain to a good independent mechanic what needs to be done.

In seriousness, it will be good to address your somewhat severe sounding symptoms in a timely manner. Part of the function of a cooled (or even non-cooled) EGR is to keep combustion chamber temps and rates down. It's not crazy to think these fully blocked circuits are contributing to the Gen 3 head gasket failure plague from detonation. I don't have fact to back this theory but I've personally upgraded Gen 3 EGR issues from performance nuisance to potential engine killer. And I've said several times now, Toyota needs to own this design fail.

 

Here are some videos from our weekend:

My Prius is down 4 quarts of oil 9000 miles after oil change

Earlier in the thread, I described how we went at the egr cooler with success:


My Prius is down 4 quarts of oil 9000 miles after oil change

While we didn't get a video of removal, that should be a good guide .

Keep us posted.

 

No problem on follow up questions .

I've done this twice:

• once with draining the coolant and plugging the hoses (lost about 1-2 ounces of coolant)
• Once with draining the coolant and lost 4-5 ounces.

If you do not drain the coolant, not only will the hoses be full of coolant, you will also have a full egr cooler of coolant.

If only removing the throttle body, you can probably clamp them, but the manifold is difficult to get out, so dodging a couple of clamps may make removal more difficult.

If you are talking about clamping the 4egr cooler hoses, it is already a constricted area, and you may not be able to successfully clamp the hoses and avoid a significant amount of coolant everywhere. If you just replaced the fluid last month, what I would do would be find some clean containers, drain it, set it aside, then put the same fluid back in. The coolant is composed of water, so extra moisture from the air will not hurt anything . Also, you would have to add coolant anyway after the amount lost, so why not try and save as much as you can, rather than end up with a lot of slick surfaces.

We used wire brushes first to clean the intake manifold passages, then went with brake cleaner. For the egr cooler, I tried compressed air up to 120 psi and there were still deposits remaining. So I'll try carb cleaner next. It should be the safest material to use, but other solvents will work.

Good luck with your weekend project. If doing the egr cooler, a second or third pair of hands come in handy.

Keep us posted and take pics along the way.

 

Did you end up doing this? Did it correct the problem? My car is doing the exact same thing. I am worried about potentially damaging something if I keep driving it this way. Thanks so much.

 

Thanks for the update and sorry to hear about the loss of the socket.

How many miles are on the Prius now? Have you resolved how much oil consumption (if any) you have? Can you quantify gas mileage now and has it only been 10 miles you have put on the car since the cleaning? Did you hold a light up to the cooler to confirm most passages were clear? Does it hesitate at all during any stage of throttle position?

As always, keep us posted .

 

I have actually a CT200h which is equipped with the same hybrid system as Prius gen.3.
I have exactly the same problem as mattcav30 has. It took me almost 2 months to try to solve the problem.
I check everything I could do(spark plug, egr pipe, egr valve,throttle body, loose clips,loose under cover...).
Now I am planning to clean the intake manifold.
However, I am quite shocked that after mattcav30 doing that much, the improvement is not very good.
Did you try to unplug the egr valve connector to disable the function of the egr? This may tell us if the problem is really on the egr system or not.

 

But.....did you cleaned the four small holes in de intake manifault? Those are the most important because when these are full of carbon your engine is going to shake.

 

Let me share my experience of cleaning intake manifold for solving the same problem.
I took down the intake manifold and the small egr gap passages inside the manifold did not clog seriously.
Anyway, I cleaned them up. I used cleaner spary and brushes to clean the passages. Not easy to make sure the cleaning was complete, since the egr passages looked like a maze inside. I am sure the small holes and passages are unblocked but not sure they are complete smooth and distribute gas evenly.
Finally, my CT still have small rattling noise under low throttle especially when backing off my throttle.
I will try to remove egr valve and clean it. It is not a easy job since it is connected to egr cooler.

 

l unpluged the egr valve connector (deactivating the egr) and drove around today.
Engine rattling remains. However, the situation when rattling shows seems a little bit different.I think the egr is not the problem or not the only problem.

 

@Hsieh2017 and @mattcav30 guys, I'm experiencing the same problem as you - engine is rattling/knocking/shaking at low RPM or when battery is low. Just paid $544 for cleaning IM, EGR Pipe, EGR Valve, changed spark plugs - didn't help the problem still exists. @Hsieh2017 after u plugged egr valve connector back in did the Check Engine light disappear by itself?
@mattcav30 did u fix the rattle?

I'm having 2010 Prius Two 169k.

Thank you!!

 

Plugged EGR Cooler - see my comments in this thread:
Engine rattle at low rpm acceleration | PriusChat