EGR Cleaning: What did I get myself into?

If you think it's hard on a Gen3, you don't want to see the gen4 or Prime.

It'll be several years before I get to 100k miles, but when I do, I'll perform the work.

Already installed and oil catch can too.

Life favors the prepared .

 

They had EGR way back in 1979?

Pixel XL ?

 

I can confirm that no codes are thrown for a clogged EGR. My 2010 (with 180K miles) was shuddering/shaking badly. It started about 5K miles ago, only at part throttle at low speed, like driving through a parking lot at 10mph. It gradually (but quickly) got worse, until it happened continuously at any speed up to about 80 mph.

Anytime the "eco gauge" display was just slightly above midpoint, the car would start shaking/shuddering bad. I pulled the EGR pipe and it was very dirty, but not plugged. Where the pipe connects to the EGR valve and to the intake manifold were dirty, but not plugged. Pulled the intake and the runners (along with the ports in the head, were very dirty, but nothing that would cause the severe shaking the car was doing.

Not until after I started cleaning the intake manifold could I even see those little 1/4" holes in the intake manifold. They were 100%, totally plugged. No way they were allowing anything to pass through - and they connect directly to the EGR passage that connects to the EGR pipe.

I spent a long time fighting the gunk in those passages. I could get brake cleaner to go through them, but there was still a lot of gunk coming out after 2 cans of brake cleaner.

I also needed more shop towels, so took a quick trick to Harbor Freight. Look around a bit and saw a "6pc tube brush set". If you are cleaning the EGR system downstream of the EGR valve (pipe and intake), get the brushes. They cleaned the gunk out of the EGR pipe and intake EGR passages in like 4 minutes. And they were like $7.

Anyway, despite the intake passages being 100% plugged, the car had no codes. No pending codes, no stored codes.

No more shaking/shuddering! It's like a new car! But I still need to pull the cowl and do the spark plugs because I bought the car used with 68K, and AFAIK they've never been changed. So I'll do the EGR cooler and EGR valve at the same time. And the coolant.

 

P0401 is Insufficient Exhaust EGR Flow. I owned a auto repair shop for a few years and saw that code often. And that code will turn on the CEL. But the Gen III Prius evidently only sets that code when the EGR valve itself doesn't open enough.

 

EGR valves were very common by the mid 70's, and at some point about that time almost all manufacturers started using them in order to meet the new emission requirements. They were all vacuum controlled back then. Take a look at the vacuum routing diagram on any late 70's vehicle and you'll go nuts!

 

Gen III Prius sets the code when the manifold absolute pressure doesn't increase (increase indicates EGR flow) when the ECM test-opens the valve during unpowered deceleration. Has to get that result two trips in a row to set the code (seeing it once only makes a 'pending' code.)

Other than using the manifold pressure sensor like that, the ECM doesn't have any direct way to tell whether the EGR valve opens or not. There is no position feedback from the valve itself. It is driven by a plain stepper motor, and the ECM only dead-reckons its position by counting step commands it has issued, assuming closed when it started.

 

Seems like a "sleepy sentry": the capillary passages seem to clog soonest at cylinder one, furthest from the EGR entry into intake manifold. Maybe number one capillary can be fully clogged but sensor still sees "sufficient pressure". Head gasket failures are usually at cylinder one.

 

My first car was an '87 Civic with vacuum lines that looked like a rats nest around the engine. After many repairs and 2k miles later, I was elated when I sold it.

 

Our first car was an 81 Civic, had a manual choke, worked a charm. Then we got an 83 Accord, had an automatic choke, which automatically stalled the car at the same red light, every morning when I was starting out. Dealership was useless, couldn't figure it out, said there was nothing they could do. Turned out to be a defective vacuum check valve; forget how I figured it out but that solved the problem.

 

I'm prepping to do my EGR cleaning, was hoping for some advice. What OxiClean product did you use? I have some OxiClean at home, but it's a powder thats marketed as a stain remover and a laundry additive. I'm thinking it's still good for use as a cleaning agent though. I'm also picking up some Purple Power today, and I have a can of brake clean at home. Will these be enough?

 

It will take hours and hours of soaking, changing the water, soaking, etc. Use a pressure washer and oven cleaner.
Depending on how clogged it is or isn't...
Brake clean will just get expensive because you'll need several cans.
If it's not too bad, just sooty, depending on your mileage and how you drive it, a pressure washer will clear it out.
But the oven cleaner will clean it.
Last time I used the pressure washer and it cleared it out nicely and fast. But I used the oven cleaner afterward.
After a 30 minute soaking, I pressure washed again, it was black coming out. I did this 3 times before it was pretty clean.

Everyone has there way of cleaning the cooler. If I had a glass beater, I'd use that!
So pick the way you want to do it, and how fast you want/need to get it done.

 

Hmm are pressure washings and oven cleaners safe for the EGR components?

 

Safe for the cooler and pipe, but not the egr valve. Brake or carb cleaner for that is fine.

 

That's what I used. Cork one end of the cooler, see how water it will hold. Mix a little less than that volume, the hottest tap water you can get, with 2~3 heaping tablespoons of the powder. Stir well and pour it in. Likely a little will not dissolve, so add an extra shot of hot water, swirl and add.

Leave it propped upright, say in corner of a laundry sink, for about an hour. There should be column of foam bubbling out, with black froth. Remove the cork, rinse with hot tap water, repeat. Five or six repetitions thus worked for me.

If it's royally clogged you may need to also run a think gauge wire through.

EGR & Intake Manifold Clean Results | Page 4 | PriusChat

EGR & Intake Manifold Clean Results | Page 4 | PriusChat

 

What should I use for the valve? I'm seeing you guys discussed about the valve being aluminum, while the cooler is stainless steel. Is the Purple Power safe for the valve? Will it be effective?

 

I used carb cleaner and paper towel. Be sure to add around a tablespoon of motor oil to coat the plunger so it doesn't stick.

 

I would just use brake cleaner and brushes for the valve. A strong basic cleaner may react with the aluminum. Maybe just cosmetic but who knows, and it's not hard to clean. Don't drench it: there are electronics. I manage to clean without removing the black plastic cap. I cleaned as much as possible, then just gently lifted the valve with a knife tip, cleaned around the edges.

 

Please don’t use motor oil to the plunger. Last thing you want to do is introduce oil to a clean valve.

Just fully disassemble the valve (2 screws) on top then go to town with the brake cleaner

 

I just used the OxiClean brand powder you can get at Costco.

Just to reiterate some previous comments, it *does* take a few soakings to get all the crud out...but it worked beautifully.

BTW - Also invest in a rubber stopper to plug up one end. See pics here :

Hi all, new Prius v owner | Page 3 | PriusChat