Still P0401 after cleaning egr !! should we drive it?

I'm sorry, I'm not a subscriber of "New York Times" - could you explain short, what you mean?

Mat

 

It was dark humor. The news was about eBay having used the mailing of cockroaches, spiders, pig-face masks, and a manual on grieving the death of a spouse, to convince a writer to write fewer unfavorable stories about them.

The link, oddly, works for me with no fuss about a subscription. I followed it from a Google link, which may involve special behavior.

 

OK - I'v got it now

I don't think, I will use the trick on him

But.. maybe I should use it on you? ))

You could listen to your EGR valve too

Mat

 

Hi folks!

Today I did another test on my old EGR valve rotor.

I tried to determine at which temperature the material of the ramp begins to soften.

I pushed the tip of my soldering iron into the material of the ramp at a point, where it would not do any damage, even if the tip would go a little into the material.

I can precisely set the temperature of the tip.

The temperature at which the tip began to go into the material was 210°C (410°F).

I think, it is very possible, that, if the inside off the cooler is covered with carbon deposite, but the exaust gas is still flowing thrue the cooler, the gases do not get cooled enough from the coolant and the temperature of the valve shaft and the stopping tip can easily get over 210°C. The exhhaust gases can get well over 400°C at he EGR cooler inlet.

If at such moment the computer commands the EGR valve to close, and holds it in closed position for longer, the stopping tip can go into or thrue the ramp damaging it.

What do you think?

Mat

 

I'm not sure I've seen anyone document what the temperature is supposed to be when the cooler is clean, or how much less cool it is later. It's a relevant question to some other temperature-based arguments that have been made, but I haven't seen anyone take it up.

I couldn't help noticing that the Prius c (and Yaris, apparently) EGR valve adds coolant hose nipples for cooling the valve itself.



They seem to have concluded at some point that cooling the valve directly is a good idea, whatever the condition of the EGR cooler.

 

Last evening, searching for plugs and receptacles for the EGR valve (I wanted to measure the voltages without back probing the plug), I found, that Toyota uses this kind of valve actuator for idle speed control valves too.

And I stumbled over a page from some repair manual stating:
"Check for operating sound from ISC valve:
Check that there is a clicking sound immediately after stopping the engine"

Very interesting

Mat

 

Decided to pull apart my old egr valve to see what it looks like inside. I’m assuming the stop is mashed? The valve was also so gummed up with carbon it took a decent amount of force to push open.

2012 | 140k miles

 

Sure looks mashed.

 

Yes... It looks smashed, but maybe not the whole way through.
Mine was shot through the whole ramp, but the plunger was actually free to move, only slightly covered with carbon deposits, which was easy to remove.

Mat

 

Hi all! Long time reader, first time poster.

I have 2010 prius with 360k km (220k miles) and I had blown head gasket. So I replace it myself and a clean EGR and cooler in sonic cleaner, so it shines. After puting all back togeather and drive it fo 200km check engine light came up and P0401. Than I start reading this thread and finde out my ski jump is bad. So I decide to fix it myself, before buying new EGR assambly. Just came from first ride and no P0401! Sure it was only 25km ride, so not sure how long is going to last, but for this shor period it is fixed.

Need to say that after my fix the magnet was stoped more distinctive than before, when I could push it beonde end point. But I did not push it too much by hand when assabling the EGR motor, to not brake it again. I wonder how much torque does that motor have...

I use bluedriver to read codes. Pending code for P0401 came right after first EGR commande position, usualy after 10km driving. I monitored manfold absolute pressure and EGR commanded position and looks like EGR is not active until engine gets hot enouth.

Will update how many km I can make with that diy repair. Attached are pictures of magnet before and after + glue I used. Hope this helps someone.

 

Back again.

So my fix last for abouth 300 km (200miles), today I try to drive pwr on highway up to 185 km/h (115mph) and got P0401 again.

So that proof this ski jump is the couse for P0401 and simple fix with my glue is temporary. First pic show how glue was scratched the same way sky jump was first time.

But I am no quitter, so try something else. I drill 1mm hole in middle of sky jump, rihght where scratch is and put in small bolt from old broken computer hard drive. Bolt itself is 1,5mm, so it screw in nice and firm. I have been considering to put glue arround that bolt, to get ski jump its shape again, in caseit will not be able to rotate the way it should. But than I try to put it back on EGR and seems no problem screwing it all the way to stop point. (when drilling hole I try to get right angle as ski jupm is)

This time I had curage to try screwing bit harder and I am confident it is strong.

No time today for test drive, but be sure I will write result soon.

 

I think it's time for a new egr valve...

 

I wouldn't be surprised if that holds for a while.

 

20km test run completed, no P0401 and EGR System smog check completed.
Now it is only mater of durability.

ASRDogman, it is my car, I do not make many miles with it any more, so it is free for me to mess it up.
If you fixing some else car I do not recomend this fix.

The reason I am doing this (and posting it here) is becouse I really hate, when you need to replace 200€+ part for something so small, like dam sky jump. I woul buy motor rotor emidiatly, it that were an oprion, but hole EGR valve for small scratch on motor rotor... That is to much.
Toyota should reconsider desighn of that small parts to last longer, does not seem to be such hard to do.

 

I understand not wanting to spend the money.
But your time should be worth something. And if you get stranded as the worse time.....

 

I have not yet had the opportunity to disassemble the revised valve they announced, to see if anything about the ski jump is different.

 

That screw should be much more durable than glue. Nothing is damaged by the screw hole?

 

That is pushing pretty hard on it (185 km/h)...
You wrote, you did some EGR test - are you sure, your EGR cooler is clean?
Pushing hard on the engine is known to be the situation, where the ski jump gets beaten.

If the EGR cooler is not completely clogged, but pretty dirty, it could lead to a raised EGR valve temperature (not enough cooling to the exhaust gases in the cooler) and the ski jump getting soft.
Then climbing a long hill or driving at max speed causes the EGR being hold closed - the hot metal notch pushed against the softened ski jump...
This is my theory of the ski jump damaging mechanism - not proven of course

And the ski jump may have its shape for a reason.
I can imagine, if the rotor gets past the (intact) ski jump, the controller is able to get it back to normal condition simply by trying to open the valve. In your case, it _might_ get caught in that spot until you disassemble it and free it up.

Mat

 

It’d be interesting to see the 4th gen ski ramp, and/or the one on the revised 3rd gen EGR valve. Metal would be better material.

safe to say the engineers were not expecting the degree of clogging, reduced cooling.

 

EGR valves for later gens, and even for Prius c if I remember right, introduced just a couple years into Gen 3, have added coolant nipples on the valve itself, for cooling the valve even when the EGR cooler is shiny and new.

The rotor never does go past the intact ski jump ... that's its point. To go past that point, it has to mash its way through.

Once that happens, there are a few ways that can reduce future EGR delivery:

1. At a minimum, the valve will always be less open than it should be. The controller simply dead-reckons position by counting the steps it sends in the opening direction, assuming the valve was at the stop to begin with. If the valve was beyond the stop, it will be too few steps open
2. As you've proposed, it conceivably could get stuck on the ski jump the other way, though that strikes me as unlikely, as it would just be retracing the path already mashed through.
3. The ski jump stops the rotation at a point where the valve is closed but the rotor has not yet wound up tight on the threads. Going past the stop, it could wind itself tight on the threads and lack the torque to loosen itself later. That exactly happened just last December to the gas valve in my home furnace, which has striking similarity to a Prius EGR valve, but with no ski jump. (Oops.)