Techstream EGR Valve Blockage Data

I du᠎nno ... you say subjective like it's a bad thing. Seems to me there's an "ok, but how subjective?" angle.

The EGR steps range from 0 to 110. In my first test, the difference between "barely noticeably rough" and "about to shake, rattle, and die" was the difference between 14-15 and 17. Out of 110.

I didn't go further to see where it finally conked out, but with that big an effect in three steps, it might have made 19, certainly not 30 or 40, as seen in some other reports.

As with any test, gathering enough data from different subjects will show us whether the range of differences that matter is so narrow that the subjectivity drowns it out, or is wide enough to draw useful conclusions even in the presence of some subjectivity.

We just don't have that amount of data yet.

 

What's going on with the second word in the above? I often want to use it, and priuschat grammar nanny "fixes" it.

 

Yeah, it's funny ... most of the PC nanny changes don't bother me as much as that one ... usually I'll just shrug and move on, or reword the whole sentence some other way. But this one bothers me every time ... "I do not know" comes out so different from what I intended to say.

 

update: with clean and newer EGR cooler and valve, i successfully entered the maintenance mode and did the EGR steps. the RPM were about 1060 (no load and warmed up engine). over #10 the idle slowed down progressively to as low as 890. when i reached #20, the idle speed would vary and some mild misfires started. i smelled sulfur exhaust again and aborted the test. I would say it is some improvement # 20 vs maybe #30, but not exactly apples to oranges.

 

I was originally playing with this just because I found the active test in Techstream, but looking in the repair manual, there is a procedure for doing such a test. It is repeated in multiple places, in the workup steps for various different engine trouble codes where the EGR could be one of the suspects. (Funnily enough, it is not repeated in the workup for P0403, the insufficient-EGR-flow code. )

P0101 is as good an example as any. Look for "PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)".

It has some specific recommendations, like warming up to 75°C or higher, not playing with EGR openings above step 30 or for more than 10 seconds, and being sure to return it to step 0 when done. The manual also confirms that step 0 is the fully closed position, and step 110 fully open.

 

That is the kind of thing I was hoping/expecting to see: before cleaning, you were having to open the valve twice as far to get an amount of EGR flow enough to roughen the idle.

 

Techstream newbie here...

I connected to the car (fully warmed, ready mode, engine off).
I found the EGR test screen.

What is the correct way to get the engine running for this test?

 

You will need to put the car in “Maintenance Mode” to keep the motor from not turning off


iPhone ?

 

Okay, maintenance mode achieved...

Now TS crashes as it tries to begin the EGR test. Tried that 2x wtih mini-vci. 1x with an openport2.0, same result. Then tried to get to AFR/O2 sensor live data, that crashed as well. I'll send an email to "tech support" (wish me luck). Pointers if ya got 'em please (TIA).

Edit: Virus protection software causing problems here (I have Avast)?

I'll try again later with Avast disabled.

 

Which version of techstream and what year is your Prius?

 

2010 Prius II, Techstream 13.00.022, mini-vci firmware 1.4.1, Win7 64 bit.

 

The techstream and 64 bit seem too new to me.

I had version 10.30.028 for our 2010 paired with an old windows XP laptop and it worked flawlessly.

Another member here tried to "upgrade" the setup and put version 12.xx.024 on it and most of the menus wouldn't function.

Ended up putting 10.30.028 back on it and it worked well again.

 

I don't think tech support will be receptive.

 

If they answer at all.

 

Try a different USB port


iPhone ?

 

I tried a) different USB ports, b) disabling anti-virus software. No change.

Edit: I see now that the CD I bought contains two older versions of Techstream. 10.30.029 and 10.10.018 along with a readme that says "Few functions in newer techstream program may have problems with some cars , so please try it again with older version techstream..."

So I guess I still have some things to try even if "tech support" doesn't come through.

I wish Toyota had an economical option for a techstream license locked down to 1 or 2 VINs.

 

Success.

I got a reply from the ebay seller, who sent me a google drive link to an install for v 12.something. I installed this and was able to get to the egr test utility and run it.

My car is 2010, 103K miles, it has not been cleaned. Oil consumption is essentially nil (lucky me). I have had the EGR pipe out and it had a thin layer of carbon all around.

I can see the MAP change when the egr valve position hits 10. By 15 the MAP has gone from 4psi to 8 psi. The engine isn't misfiring, but it's beginning to struggle a bit. I conclude my EGR system is working pretty well for 100K miles and that there is no urgent need to clean out the cooler & valve. I do plan to inspect/clean out the manifold before too long.

 

Almost exactly one year after my first check and now at 154,000 miles, I'm seeing unchanged results of step 14 to 15 for noticeable roughening of idle, 17 for extra badness.

I would guess mine is still flowing just about as well as last year.

This time, for curiosity's sake, I have removed the manifold and the EGR pipe (none of the rest of the EGR system for this weekend).

There was a layer of deposits about the thickness of paper around the inside walls of the EGR pipe and manifold passages. The cylinder 1 EGR outlet had maybe a just barely discernibly thicker layer than 2, 3, or 4.

I cleaned the passages out using some stiff nylon and PEX tubing I happened to have around in suitable diameters.

My manifold turns out to be the original 2010, -37050 one, with one big straight EGR passage right through it that the four outlet passages join perpendicularly into. At least that makes it easy to clean.

Also had the chance to see the intake valves in the head for the first time. Pleasingly clean and free of deposits. Interestingly, the intake ports have some carbon deposited in the outer portions (again maybe as thick as paper), from the manifold to about as far in as where the injectors come through. Everything beyond that point is quite clean. Must be something to those detergents in the top-tier fuels. I haven't been running any extra cleaning additives.

With the carboned-intake problem being that the carbon soaks up fuel and messes with mixture, I guess the existence of some light carbon only upstream of the fuel injectors doesn't seem like much of a concern.

 

I should add here that I found a similar, but easier, check available in Techstream: rather than manually, yourself, using an Active Test to move the EGR valve and see what the manifold pressure does, you can ask the ECM what the result was the last time it performed that same routine as a self-test.



It may not be directly comparable to what you see doing the active test at idle, because the ECM does its self test under driving, decelerating conditions instead. But it is very easy to go in to Techstream and pull up the most recent saved result.

The one in the picture is from the same car as in #39, about eight months later (and very little driving, COVID, don'tcha know), to give one idea how the two test results and the visual check result may relate.