Techstream EGR Valve Blockage Data

Yeah but to but to be that close, and exerting extra effort to leave the cooler in place; I couldn't do that. OP's miles are low too, cleaning cooler would be easy.

Draining* a couple of quarts of coolant prior to disconnecting the cooler's coolant lines, you don't spill anything, Well maybe a trivial vestige.

* Into a clean container; pour back into reservoir after.

 

I wanted to add some data I gathered on a recent drive to a cold weather climate. I was there for a couple of days and the weather never went over 40⁰ and averaged in the high 20⁰s. My readings are usually in the 18-19 kPa range in Socal (70⁰s) in the low temps during my trip my readings were consistently lower between 12-14 during hwy and ciry speeds. As soon as I got back to a warmer climate my readings normalized to 18ish.

Not saying it's causation, seems like a correlation. I took around 10-15 readings and all were consistent. Elevation during normal readings around 700'-1000', cold weather elevations were 2500-4500'.

 

Interesting. What's the atmospheric pressure difference in kPa between 700'-1000' and 2500-4500'?

 

Difference between 1000' and 3000' is around 7kPa

 

Hello all,

2014 Prius here just hit 130k. Recently changed spark plugs (a little late).

a friend who also has a Prius and blew a head gasket put me onto the EGR issue and I’ve been a little stressed. However my results have almost been too good to be true. I seem to be getting the same results as a just cleaned setup.

Over the past weeks I’ve gotten the following results:
21.11
21.52
22.3
21.99

some background on the car, I bought it used in 2018 with 70k from a Toyota dealership. They had offered the certified warranty on it but I declined. Most of the 60k miles I’ve put on it have been ubering in nyc. Oil changed with Mobil 1 every 5k since I’ve owned it.

I was planning to clean the whole system, but now I am thinking I may just start with the manifold passages and pipe.

 

Interesting! Those are figures supposedly typical of new or freshly cleaned-out coolers. At similar mileage, I got higher-than-expected flow-test values too, but not that high---more like 18-19 kPa.

Let us know what you find in the manifold EGR passages, please.

 

Hi folks!

Short update on my EGR flow (see a table) and a concern...

Recently, my dear Prius rattled on me on start...

I had the rattle one or two times already, but it was the famous "short engine on" story - the next start you have rattle - no-brainer.

This time, I have trouble remembering having a short ICE start before rattling...

If you wish, you can look into attached reports (PDF-files) - one from 21.09.2022 (no rattle then) and one from 29.04.2023 (rattled two times recently). One can see misfire issues in the second one.

What do you think? I'll drive it today about 2x 16 km - I will listen for rattling and will make new reports - lets see if it was intermittent or not :|

I know, this thread is not 100% appropriate for this - but you are the experts

Mat

Edited:
Added two attachments:
Diagnostic Report 2023-04-30 153454_no_VIN.pdf
Diagnostic Report 2023-04-30 200621_no_VIN.pdf

Through the last two drives, there seems no misfiring events being detected.
The "Exponential Weighted Moving Average" of overall misfires is going down (look for "Mode $06 - On-Board Monitoring"-table in the PDF-documents).

Interesting is the EGR data from the last two drives - the EGR flow value is over 20!

I have to monitor the averages of the misfire count - hopefully it was an isolated event

Mat

 

I just want to throw out there, for those using brake clean, Carb and Throttle Body cleaner works lightyears better.

 

Hi all,

2012 Lexus CT here. This thread helped me a lot identifying the issues with clogged EGR/Intake, so i wanted to share my values for comparison.

But first some background of the car and conditions:

2012 Lexus CT, bought it with 40k miles on the clock in 2017
currently 144k miles on the clock
5k OCI with 0W-20 (API SP, GF6-A)
Transaxle fluid every 60k miles
Coolants every 50k miles
Sparkplugs every 100k miles
Fuel is 95 octane
No oil consumption
Maintenance is all DIY
Avg. mpg on last 104k miles is 53 mpg, tracked everything since i bought it

Driving profile is 75% highway, 25% city driving. I am pretty calm driver, i barely go over 75 miles/hour.

Ok, now the values of my last readings(2 weeks):

18.37 kPa / Min 0.99
18.41 kPa / Min 0.99
18.59 kPa / Min 0.99
17.81 kPa / Min 0.99
17.87 kPa / Min 0.99
18.39 kPa / Min 0.97
18.98 kPa / Min 0.97

I think the values are not too bad compared to freshly cleaned EGR/Intake with around 20 kPa, 21 kPa. I am not sure if it is worthwhile to clean everything yet. I might have a look at the intake but not clean the complete EGR. Yes, i am procrastinating

I also have no idea why the values are still ok for 144k miles. Is it the high amount if highway miles? Could quality of fuel have something to do with it?

 

Try a tank of regular.

so EGR and intake manifold not touched yet?

 

RON 95 is "regular" here in germany, premium fuels are RON 100 or above.

I have not touched EGR/Intake yet. But don't know if something was changed between 2012 and 2017, before i bought it. Is there a way to check if the car has the upgraded versions of the EGR-Valve or Intake Manifold? Any details visible from the outside?

 

This is a CT 200h? Not sure, doubly not with European spec, but I think it's propensity to carbon clog will be the same as any gen 3 Prius, ie: a certainty. There was an EGR valve and intake manifold "upgrade", but I don't think it accomplished much, if anything.

Fourth gen prius did have a major revision, and it worked.

 

Agreed, with those numbers I would feel comfortable leaving the bulk of the EGR system alone for now. The intake manifold is easy to remove and check, and I would do that, just because (1) it's easy, and (2) differential clogging of the four little passages there may spell trouble, even if the overall flow numbers are good.

 

Has anyone tried fuel additives that promise to clean catalytic converters and EGR-Systems? Maybe that helps to prevent clogging or even detach the build-up carbon? I have no idea how this works, but i see some quite good reviews on these products...

 

I can't see fuel additives doing a thing.

 

The question comes up pretty regularly, probably some number of times right in this thread.

The first thing that comes to my mind is that I've seen more cleaning substances advertised to clean the parts of the fuel and induction system that are ahead of combustion. After combustion, the substances are probably other substances.

But I haven't tried them myself.

 

Adding my results. This is on a 2012 Plug in Prius, ~160k miles, first cleaning i'm aware of. More details on the car and cleaning are over here: Do all Gen 3's (2010-2014) need EGR Cleaning? | PriusChat

Results are below. using Car Scanner Pro and the "noncontinuous monitors" to pull this. results were pulled from different days.

 

Just thought to check this again today.

16.42kPa with no further EGR or intake cleaning in the last 2 years. 175,000 miles (~15k more than my first readings 2 years ago).

Reminder: this is with a never-cleaned cooler. I DID clean the pipe and intake manifold 2 years/15k miles ago, though.

 

2012 Prius with 200,000 miles

Value: 20.89 kPa
Minimum: 0.95 kPa
Maximum: 655.35 kPa

Never cleaned any of the EGR parts. I'm going to put off the cleaning the EGR parts a while longer because it sounds like a lot of work!

 

Wow! That's unusual!

What gas are you using? Something special?

Mat