Swapping in a Gen 4 Prius' 2ZR Engine into the Prius v

Could that corrosion be errant oven cleaner or similar??

 

At least judging from needing the power tool on the screws, I didn't have the impression anyone had been in there before.

There are a couple downward-facing openings into that chamber, so it isn't completely sealed from the environment.

 

Could I have actually damaged the new EGR, stepper motor or anything when I switched the red and purple wires like the previous posts had mentioned??

 

Which ones were those again?

 

Huh. Did you post that as an image because it was easier than a link?

You'd think a search like this would be able to turn that up, but for me it isn't....

Edit: ok, guess it was in a Conversation, mentioned here.

So apparently it was RightOnTime who supplied that information "some time back" (from January 30th), but who also said recently

If my eyes don't deceive me, this photo seems to show pins 3 and 4 being swapped, not 1 and 6. Remember that the pinout drawing shown above is as seen by a person looking at the valve.



So EGR1 and EGR2 were getting swapped.

Mendel posted excerpts from both Repair Manuals over here, and they both show the same pinout of 1:EGR4, 2:+B1, 3:EGR2, 4:EGR1, 5:+B2, 6:EGR3.

In that post, apparently Dave Hanson is crediting Sandog58 with having "figured it out".

Sandog58 isn't mentioned anywhere on PriusChat but that one thread, and maybe isn't a member.

The 2010 manual does have this sequencing info:



This is at idle, so that apparently is the sequence you use to drive the valve in the closing direction: EGR4 EGR3 EGR2 EGR1 EGR4 EGR3 EGR2 EGR1 and so on.

(Funny, I had always pictured the ECM trying to learn where 'closed' is and then stop sending signals, but if they're saying you can scope this pattern any time you're idling with a warm engine, then the strategy must be whenever the engine is idling, the ECM is just constantly whispering to the valve ... psst ... close ... close close close ... close close close close .... Sure, that would work without having to learn much. Then when you're driving under load and it wants some EGR, it's pretty sure 'closed' is where it's starting, and can count up the right number of steps.)

So swapping the top two waveforms looks at first glance as if it would just kind of trap the rotor wobbling back and forth between two steps. But the reality is even funnier. The diagram up in #344 shows the motor is made with two distinct center-tapped windings, fed with battery voltage at their middles: EGR1 and EGR3 are the two ends of one, with EGR2 and EGR4 being the two ends of the other.

Swapping EGR1 with EGR2 changes their allegiance. Now what you've got is two center-tapped windings, each of which is half the time completely off (not grounded at either end), and the other half the time pulling in both directions at once!

Oh, to ask Sandog58 where the idea came from.

Could it be as simple as, Toyota switched the wire colors for EGR1 and EGR2 between years, and Sandog58 assumed that meant the circuits had to be swapped?

Or was it just dreamed up as a way to do an "EGR delete" that the ECM wouldn't immediately catch on to with a P0403?

 

My bad, should have said Sanddog53. He posted on page 10 of this thread, about this.

 

Hum! @RightOnTime, it looks like you've got a valve of each kind there (post 337). Or were those just the two Gen 3 versions (-37110 and -37120)?

Looks like Gen 4 are -37140 or even later -37150.

It should be easy to see if something has changed in the pinout. The Gen 3 valve has the two separate center-tapped windings on the two rows of pins in the obvious way: pin 2 is the center tap between pin 1 and pin 3, and pin 5 is the center tap between pin 4 and pin 6. An ohmmeter should see about 20 Ω from pin 2 to 1 or 2 to 3, and from pin 5 to 4 or 5 to 6, but there should be no continuity between any of the bottom row pins and any of the top row pins.

If that somehow changed with the newer valve, that could explain the repinning.

But wait ... that test procedure is still in the Gen 4 manual bit that Mendel posted:



... and with no differences.

@Sandog53 reported having "tested the wires with a multimeter" ... it would be great to know what was tested, and what conclusions that led to.

 

Damn this issis getting deeep. Luckily I own a multimeter so I can go get some ohm values and check continuity between rows.

How come we can't get a circuit diagram for the 2016 EGR valve. I will try to grab my part # and then see if RightonTime is running the same gen4 EGR part#

Edit: btw, I have never had any "misfire codes" since the swap,

Dave henson did you swap EGR wires because you were having problems or just because sand dog did it?

 

Who says we can't? I'd bet the drawing I found in 2010 is in the 2016 manual in some very similar form.

So far Mendel has been the copy-n-paste-from-Gen-4 guy. Find out his beer preference and work something out.

 

By the way,

My EGR is 37140, ohm readings are consistent with the chart provided above. Engine cold, outside temp 67 F.

2 and 1: 19.3
2 and 3: 19.4
5 and 4: 19.4
5 and 6: 19.2

No continuity between rows.

 

That would indicate no change between generations in the way the motor operates. Maybe Mendel can find the Gen 4 versions of the circuit diagrams and scope traces seen in #344 and #346. At this point my bet is they'll be no different from Gen 3.

Making it all the more interesting to hear what @Sandog53 saw that led to thinking those pins should be swapped.

 

One of my very selfish motivations for hanging out here, is to learn from the experience of owners further down the road. It seems like swapping in a fourth gen EGR is not without perils, if indeed the 3rd gen's computers don't quite know how to handle it, it's got different performance parameters.

My take now, if I was ever in the engine-swap scenario (and with the glacial pace of our odometer it's highly unlikely), I'd get the head rebuilt by a machine shop, stay with 3rd gen EGR (cleaned well), and a new short block.

@michaud85 has some links btw.

 

What I'm seeing at this point in this thread is that nobody knows very much yet about why michaud85's engine is performing strangely, and there have been some ideas about EGR that aren't being borne out by evidence, and it would be good for everybody to find out more.

@Mendel Leisk, you have posted some excerpts from Gen 4 repair manuals earlier in this thread. Do you still have access? Is there any chance you could look for the EGR wiring picture and the scope waveform pictures that correspond to the 2010 ones?

In the 2010 manual, the oscilloscope traces are sort of early in the engine diagnostics section; there are a bunch of scope traces for different signals, grouped together right after "terminals of ecm".

The how-it's-wired picture is in the troubleshooting steps for P0403.

 

@michaud85 has links to all my info. Might still be downloading? Maybe post search string suggestions for him, here?

 

The oscilloscope graph for EGR function is identical in the Gen 4 Manual(see below). I havent found circuit diagram yet, the manual is over 12000 pages...

Im going to sort this out though. I will have to get an MVCI cord and run techstream on the old windows 7 laptop i keep around just for occasions like this.

I found the EGR step test procedure in the gen 4 manual so i would like to use techstream to test my egr valve, only because my symptoms go away when I unplug egr,

However, for my syptoms of hesitation and poor acceleration the manual does not even list EGR as a culprit for that problem. It does list EGR as a problem for rough idle, which i was experiencing when I rewired the EGR for no reason. I am wondering if I maybe screwed the valve up somehow swapping those pins and running the car like that for 1000 miles.

Anyways i will test the valve and swap if it does not pass the test. If the valve passes performance test then I will start troubleshooting from the beginning, maybe the MAP sensor has some debris on it or something.... Maybe there is a cut in a vac line?

All i know is the car has a ton of power when its floored but when you let off throttle completely and suddenly or only give it a little bit of throttle it does not operate smoothly.

When you start the car with a cold engine the engine seems to idle unusually high initially but then settles down(not sure if that always used to happen or if I am hyper vigilant now).

Just installed K&N filter which makes me feel like an idiot, but at least they are re-usable. Will Update with any additional findings. May take some time because I have to order this funky chinese techstream cord. Let me know if anyone recommends a particularly less shitty one.

I will say, one thing I thought about and heard about was the hybrid battery causing problems lie this, when I initially ruined the gen 3 engine and my gf drove it home that fateful day, the overheated engine could barely power the vehicle, she said it was struggling to maintain speeds)and I think maybe the battery was given a gauntlet run that left it weak.

 

Not sure myself, but don't believe I've got 4th gen wiring diagrams. Second gen version I have has wiring diagrams at the end. Third gen it's a separate file, same folder. 4th it's just the one file, maybe no wiring diagrams, at least not the big/complete bundle.

 

We confirmed the EGR pinout is the same with Both Gen 3 and Gen 4.

No need to worry

 

So this whole red purple thing is just trash, may have been chasing the wrong suspect all along. What is your EGR Part # just to confirm @RightOnTime?

Well that is actually pretty good news for me because that means I should be able to fix whatever is is causing this....

 

I am still sort of hoping @Sanddog53 might come around and explain where the idea came from, but yeah, when you actually do that swap, it just means your EGR valve can't move, so it'll be stuck OFF and you haven't got EGR.

But the topic of this thread isn't just EGR, it's the whole business of swapping a Gen 4 2ZR into a v. So you're still doing that, and if it isn't running perfectly yet, there's still legit stuff to talk about. EGR might turn out to be all of the explanation, or some of the explanation, or not much of the explanation, but it would still be satisfying to get the engine running right.