Topic: Emissions fail, advice?

[Gnarly4X]

I should note I am using 7/64 hose instead of 3mm. It is a tiny bit smaller. Would that matter?

7/64" is .109357 inches.  The difference between 3mm and 7/64ths is .00866"... I don't think the vacuum is going to know the difference.  But I'm just speculating.

Gnarls.

[andykrow [OP]]

Yeah, I just read someone saying to be sure to use the 3mm hose.

I really don't want to throw money at this, but I guess I could try a new egr valve. Mine is definitely not fully plugged but it could be not letting enough exhaust through. With a baffle in place I certainly should be getting a stumble or stall when applying vacuum directly to the valve.

My understanding is this does not take a lot of vacuum to actuatate. And I sucked pretty hard, haha

[andykrow [OP]]

The egr source is internal to the head, right? I had a shop put the motor in, there isn't any way they could have blocked it off is there?

[Gnarly4X]

More backpressure doesn't affect the mixture.

It affects the EGR and modulator.     More exhaust in the intake = less NOx.

Look at the modulator and EGR and hoses in Snowtoy's post.


When the bottom of the 'T' is closed,  full available vacuum is applied to the EGR  (if the BVSV is working correctly,   BVSV is so EGR doesn't work when cold,  you can bypass as smog test is for warm conditions)

Backpressure at the bottom of the modulator and vacuum in the middle will close the bottom of the 'T'

But (this is from memory)  the middle chamber also has a controlled vacuum leak.   So if there's low backpressure and not much vacuum the bottom of the 'T' is never (or rarely) closed.    So you never get much vacuum to the EGR valve to open it up.

Toyota designed the system for the stock exhaust and muffler.     Any changes to the exhaust and you've messed up Toyota's calibration.

The plate I made was just a educated guess and it worked................

So if the EGR is not working at idle (full vacuum), then the mixture goes lean?

Gnarls.

[Gnarly4X]

The plate I made was just a educated guess and it worked................

For testing purchases, will a potato stuck in the end of the exhaust pipe work to create some back pressure? 

Gnarls 

[emsvitil]

Some exhaust has to escape, so drill a hole in the potato first..........

[andykrow [OP]]

So if the EGR is not working at idle (full vacuum), then the mixture goes lean?

Egr definitely should not be working at idle. The test, at idle, is to apply vacuum to the valve, which opens it, letting exhaust into the intake and causing the motor to stumble or die. Mine fails this test.

I do not believe the egr is affecting mixture. It's purpose is to lower combustion temps which will reduce NOx. NOx is caused by the high temps which can be made hotter with a lean condition.

[emsvitil]

EGR has nothing to do with mixture.    Exhaust gas is inert since there is no (well, very very very little) O2 in it.

[emsvitil]

Did you apply vacuum directly to EGR? (leaving modulator out of it)

[andykrow [OP]]

Yeah. Direct to the valve. I can confirm the valve at least moves and is not fully plugged. It could be too plugged to work though. That's kind of my only hope.

[Snowtoy]

The BVSV also plays a role in the EGR system,

[emsvitil]

The BVSV is there so there's no EGR until the engine warms up. (any vacuum that would otherwise go to the EGR valve is lost)

Failing in the below 30C mode would mean the EGR won't function.

Failing in the above 44C mode only means the engine will run slightly rougher when cold.


Since a smog test is run when you're engine is warmed up,  hope that if it fails, it's in the above 44C mode (like mine did years and years and years ago).

[andykrow [OP]]

I have a vacuum gauge and tested the system in that regard, per the fsm. I was able to get vacuum at 3000 rpm like the fsm states. BVSV at least was open at temp. This was before I even cleaned out the EGR, where the small stem that goes to the modulator was completely plugged. So it appears that stem does not need to be functioning in order for vacuum to get past the modulator and to the valve.

I think I am going to run it through today, with the baffle in place and the slightly functioning valve. Maybe I can squeak by. I am going to not warm the engine up, just drive the 3 miles to the testing place. The purpose of the warm up is a more complete fuel burn, and I do not have that problem in the least.

[andykrow [OP]]

I found the results of the test with this truck from two years ago. Stock head and cam, and an open exhaust. It got through with NOx on the very high end of the scale, 5.5/6. So it seems that on my truck at least egr was not working back then.

HC was much higher on the motor, by an order of magnitude. It was old tired motor and that would be expected.

It might be reasonable to say that in a truck with a fully functioning emissions system the 261C will not push the truck into failing emissions. It may be causing a lean condition that is then causing high temps and higher NOx - that seems possible but I am not ready to make that claim just yet.

I find it likely that the bigger culprit here is the open exhaust and higher flow head. Again, back to my wrx days. Just swapping exhaust from the turbo back (downpipe to tail pipe) can cause you to run dangerously lean, on a far more advanced EFI system. And here we have high flow equipment, much higher flow than stock at least, with no corresponding adjustments to the efi system. I think that adjusting the AFM gears at least may be necessary in this scenario. I would think the ECU would learn the new setting and adjust in closed loop, but in WOT open loop? That is where I want more fuel put into the system.

I think a wideband o2 is in my future.

[Toyotadon]

Wait, what are you using to apply vacuum to the EGR valve?  Your mouth?

Sorry, that won't do it.  You could take a vacuum source from the engine, or go get yourself a vacuum tester, such as this one.
http://www.oreillyauto.com/site/c/detail/LIS0/75000/N1745.oap?ck=Search_vacuum+tester_-1_-1&keyword=vacuum+tester

[andykrow [OP]]

Yeah I used my mouth. I had read somewhere that should be sufficient, that the egr does not need much pressure to actuate.

I was able to generate 5 psi or so doing that with my pressure gauge. Not enough vacuum?

As soon as the rain clears up I will try the test with direct manifold vacuum.

[Gnarly4X]

Hey andykrow,

How many 22RE's are out there with over-sized valves, headers and free-flow cats/mufflers running 2.25" to 2.5" piping that DO NOT have a lean mixture issue?  If adding headers and open exhaust on a stock 22RE was causing a serious lean fire condition, wouldn't we know about before now?

Were the injectors tested or refurbed? Like me, I assume you don't know or have not tested the fuel pressure?

Gnarls.

[andykrow [OP]]

Indeed I have not tested fuel pressure.

Part of the issue here is I really do not know what this NOx number actually means. It is the limit the state of Colorado has somehow determined. If I am over it does it mean my truck is actually lean? This is why I am thinking of getting a wideband so I can actually know what is going on. Determining that a motor is lean by NOx is not very rigorous. I am certainly not so lean that I have a miss or pinging.

As I was mentioning, my previous truck now owned by a close friend - (30k on motor, DT and open exhaust, 252S cam) just barely passed the NOx, and that was on the third try. After the first try failed we retarded the timing a bit which got NOx down but it still failed. He then bought a new catalytic converter and it just squeaked by. It's possible that all of that change was due to driving differences by the tech, as the catalytic was fairly new and put in by me when I owned the truck.

EDIT: I never tested the EGR for my friend, I will try to do that in the next few weeks and see if his is also not doing anything.

[andykrow [OP]]

If adding headers and open exhaust on a stock 22RE was causing a serious lean fire condition, wouldn't we know about before now?

Were the injectors tested or refurbed? Like me, I assume you don't know or have not tested the fuel pressure?

I have to agree, if there were a serious lean fire condition we would likely know about it. Question is, do my NOx levels indicate a serious condition. I do not believe so simply because I have no miss nor pinging, and it drives so damn well.

Injectors were sent to witchhunter, which was a waste of money. Everything tested well to begin with.

[Snowtoy]

Ugh, baffle in place and egr still doesn't want to make the car stumble.

With not being able to get the engine to stumble/stall, I would check all of the plumbing and ports, with it barely passing yrs ago, the problem may not have anything to do with the new cam, the way you found the vsv connected to the charcoal canister, that could have been done by the PO or helpful smog tech to get it to pass.

[andykrow [OP]]

I know that I have the vacuum hoses all connected properly.

The question now is why is there no stumble? So it would seem that either the egr valve is too junked up to pass enough exhaust, or for some reason the port on the head is not supplying enough. The stumble did not happen with a baffle in place so I do not think backpressure is my issue.

[andykrow [OP]]

The vsv was the one that should be connected to the fpr. Verified by looking at friends vacuum plumbing. Pretty sure there is no effect on smog with that.

If anything, not getting some vapors from the charcoal would hurt my cause.

In any case the first time I ran through I left the vacuum as it was. After the first failure I realized it was wonky.

[Gnarly4X]

Did you verify that the vacuum tubing is not plugged and the port(s) on the chamber are providing full vacuum?

Gnarls.

[andykrow [OP]]

Back when I teed off the line going from modulator to the valve and check the vacuum, it passed according to the fsm. This is the check to see if the system is applying vacuum to the valve when it should.

The issue is the valve. When applying vacuum directly to it, (bypassing the cars EGR control system,) the engine should run really rough or die. It does not do this. So at this point, the controls don't actually matter because the valve itself is not putting exhaust into the system.

[Snowtoy]

So at this point, the controls don't actually matter because the valve itself is not putting exhaust into the system.

Or maybe a clog somewhere before the EGR.

[Gnarly4X]

Have you pulled the plugs, disconnected and reconnected the battery, or done a compression check?

Gnarls.

[andykrow [OP]]

Or maybe a clog somewhere before the EGR.

I hope this is not the case. This is a brand new head, and as I understand it the EGR plumbing is fully internal on the head, there would be no way to block it off. With the valve removed last night I could see that nothing was blocking the port on the head, at least.

Have you pulled the plugs, disconnected and reconnected the battery, or done a compression check?

Have not pulled the plugs or checked compression. I did disconnect the battery yesterday.

Anyway, third time through and another fail. So, at this point I have to get the EGR system working. I need that idle-test stumble. Looks like I'm buying a new valve. Ouch. I will run a few hundred more miles on it and then check compression and plugs.

I think before I run it through late next week I am going to return the AFM and timing to stock settings, and include a baffle to slow down the exhaust a little.

I am out of town through next Tuesday so this is going to have to wait until then :/

[andykrow [OP]]

I suppose next week while the EGR valve is off I could start her up and see if exhaust comes out of that port.

Also, I didn't even think to look, is it possible that the intake plenum is clogged up? Does it have any internal plumbing in it for EGR? I thought it was just basically a hole in the plenum so very little chance of clogging. I guess I should look into that before I order a new valve...

[Toyotadon]

I was just thinking to suggest starting it with the valve off.  If the intake port is actually clear, it will barely run due to the vacuum leak, but you should be able to hear a good popping sound from the exhaust port.

[andykrow [OP]]

Yeah I am going to do that. I'll plug up the plenum with something to stop the leak.

From looking at some photos, it looks like the exhaust exits the rear of the head on the exhaust side, the goes through the back plate (I think for cooling and contact with the coolant inside the head?), then back into the head at the rear on the intake side, and then out again at the EGR port the valve bolts up to. The shop that built the engine would have had to purposely block off the ports that the rear plate connects to. I don't know why they would do that without talking to me, and since this county has emissions that would be dumb. Stranger things have happened I suppose.