Techstream EGR Valve Blockage Data

Good catch on the units. Those had better be kPa!

 

Here's mine. Cleaned EGR, intake and MAP sensor 2 days ago.

Wish I'd performed a test prior to cleaning.

2012, 100k miles

 

Well, I did add a turbo to my Prius.

 

Out of curiosity, I checked the test results again today (and I still have NOT cleaned the EGR cooler or valve) to see what sort of variation there might be in test results.

April 7: 16.17 kPa
April 16: 16.28 kPa

They're different enough to know the test ran again but still really similar. I'll try to do this a few more times to see if there's more fluctuation. While we can't definitively say what the target/threshold number is for healthy/unhealthy EGR, it would be nice to know if the results are consistent so that a single test is all you need.

 

Thanks for doing that. Measures of test-to-test variance without changing anything are definitely part of the picture we need.

 

OK joining the club.
Prius 3 2009, 192,000 miles, no idea what maintenance previous owners did.



No problems with coolant, 10 ounces of oil at 6200 miles. Car runs and sounds normal.
No idea what that value means. Good? Bad? So-so?

 

To clarify, this is a 3rd gen, same as North American model year 2010 through 2015?

appreciate around the world the identification can vary.

 

Well, the observations we can make so far are: it's about twenty times the minimum to pass, it's roughly like what Emmanuel Isaac had upthread, before cleaning, at 51,500 miles ... it's not quite as good as wheezyglider's 2012, it's somewhat better than AW82's 2012 at 158,000 miles (correcting for that scan tool saying "psi" where it clearly has to mean kPa), it's not quite as good as the 20- to 21-ish numbers reported a couple times right after cleaning, and it is way, way better than what ozmatt got with an EGR valve that didn't work.

Ideally, as we get more of these numbers, we'll also get information to go with them: the corresponding after-cleaning numbers, photos of the coolers, it might be nice if some folks could also independently measure airflow through their removed coolers, if we could come up with some easy reproducible way of doing that.

Going by only what we know so far, I'd say it probably isn't telling you of an urgent problem.

 

IIRC @mjoo has tested before and after water flow; would that be helpful? Maybe along the lines of “time required for a quart to pass through”, or “volume passed through in a minute”. I think easier to measure.

 

That could be pretty easy and repeatable, but would call for being very consistent in the shape of the quart container and its height above the cooler being tested.

 

Did a third reading today with no additional egr cleaning. A little more variation than last time. I do have BG 44k in the tank right now. It's gone about halfway through. Doubt that has any impact, but...

April 7: 16.17 kPa
April 16: 16.28 kPa
April 24: 17.14kPa

 

Yes, same 3rd Gen.

Thx ChapmanF.

 

If we're making the ideal wishlist, I'd also suggest photos of the intake manifold EGR port cloggage. (Do we have a correct term for those small EGR holes?) Specifically: a water hose at the EGR inlet (where the EGR pipe normally goes) can visually show the unevenness of distribution to each cylinder.

We would want to correlate that with mileage since new or last cleaned. This could be useful in nailing down maintenance recommendations, because we already know that those ports clog unevenly long before the cooler is clogged, and can begin to cause misfire DTCs if nothing else. As @ChapmanF had suggested elsewhere, even if the EGR flow monitor shows good, we could still recommend an intake manifold cleaning interval.

I'll admit it's a tricky photo to take without an extra pair of hands to hold the camera, and the result is sensitive to how level you keep the manifold. But even without lab-grade conditions (controlled psi) the visual evidence is telling.

 

That would be nice to have, but I think the point here is to draw parallels between a simple OBD test and conditions within the EGR system. There aren't any sensors that would apply to uneven intake manifold blockage.

 

Forgive me for thinking the bigger picture is to make use of the (so far rare and mostly missed) opportunity to have willing participants gather useful data before cleaning EGR. Preferably a checklist of items like the one proposed.

[With just a bit more data, the odometer *becomes* the indicator of probable IM cloggage, is the hope.]

 

May 7: 16.48kPa
Still have some 44k in the tank.

 

I finally got a clue, and followed you over from the Prius V thread to this one. My questions are mostly answered. I managed to find an install of TS that worked. I found the EGR Monitor data, and I took a screenshot:

View attachment 212016

This is the result of the the most recent EGR test on my 2017 Prius V at 94,290 miles. It is June 22 2021 in Philadelphia. It has been humid, and temperatures have ranged from 70 to the low 90's over the past week. This 2013 was driven 300 highway miles about a week ago to pick up my 2017 Pruis V. This 2013 has seen a few days of short trips and at least 1-2 days of my wife commuting 15 highway miles each way to work. Nothing unusual. No Uber driving yet.

I found a place to clear all of the monitors, but the data persisted. The I fiddled with some other features, like putting the car into inspection mode. I checked back, and the Monitor data was now cleared. With the data cleared, I can run the car around and get some more data points before I start taking the EGR beast apart. If I postpone the EGR surgery until next week, I can get 20+ hours of Uber driving as a test this weekend. I'd like to get 5 EGR monitor tests from before the EGR Surgery.

It would be helpful if someone can post the "confirmation driving pattern" from the repair manual section for P0401.

 

There was an issue posting the image. ChapmanF: I can see you are online, I would like feedback if this is helpful... How do I contact you through the chat?

 

It is helpful to have the information contributed. I'm not sure I can say very much specific to your result value; that looks to be within the range of variation so far seen with systems that aren't freshly cleaned but aren't about to log a P0401 either.

Part of the appeal of gathering as much data as possible is that one day it may be possible to say something more about what a 14.76 suggests compared to a 12 or 16 or 18, but we're just not there yet.

 

You are preaching to the choir here. @94k miles, I don't expect the blockage to be bad, but worse than the 51K data point from above. I should point out that at least 50% of my miles are while driving on Uber. A data point is a data point.

My understanding is that you would like a few distinct EGR test results of before and after because there is variability between EGR tests. I was planning on giving you 5 before values and 5 after values. If I could give you the same data via a phone app, I won't have to lug my laptop with me during Ubering this weekend. I can extract data from my phone while I eat dinner. I can't find my Bluetooth ELM 327 adapter, but I purchased a replacement on Amazon, which I will have by late Thursday. Are you OK with results extracted via the Android "Car Scanner" app?

BTW: What is the "IN VVT STUCK B1" all about? I assume that "VVT" is "Variable Valve Timing", and "B1" is "Bank 1". I am surprised that VVT data would be lumped in with EGR performance. For the moment, I am not paying attention to it.