UPDATE: Passed!! Wrap up at the end of the thread.

Stock 5.7 with a mild cam and BBK 52mm TB. Engine has 2,000 miles on it.

Cam:


Just missed the NOx. 650 vs 450 to pass. Last time when my EGR was not working, NOx was 1200+ so I am close.

I am buying a new Walker California Catalytic (not sure how old the one is in there but it looks fine), Scott Hansen sent me a slightly richer tune but said everything looks good and suggested I check/replace the EGR temperature sensor. My smog pump is hooked up, about three years old, and diverter valves functioning (last time I checked).

Any tips/tricks?

 

Increase the 02 sensor voltage switch points about 0.200v and retard the ignition timing table about 4°.

 

This was from the last year my old G20 van had to pass the emissions dyno. TPI with Vortec heads and no egr, no air injection, had newer heavy load cats and thorley tri-ys. If you have some room on the HC and CO readings, retarding the timing and slightly richening the air/fuel in closed loop will cool the combustion chamber and choke off NOx formation. It passed with a fraction of the allowable limits. In factory form it was carbureted with dual air pumps and no cats.

 

Sorry you are having to deal with this good luck. Sure glad I live in Northwest Ohio and don't have to deal with all this government BS. Make sure to tell Pelosi and Biden thanks for costing you all the extra problem and Money. Better voter her back in. lol sorry just popped into my head.

 

I'm with you Randy, but, I do acknowledge that the difference in air quality in SoCal, where I grew up, is as clear as the difference between night and day. Every night after a day of playing as a kid in the summers, my lungs hurt. All of my friends' lungs hurt. We had Stage 1, 2, or 3 "smog alerts" almost every day. Only late fall would the air quality improve. The state of CA did drive the development of the catalytic converter and that made all the difference. Yes it can be a pain, but the quality of life benefit is very real.

 

Thanks I will send to Scott.

 

Believe it or not, sometimes if you're real close to passing a fresh oil change will do the trick; the PCV system draws in crankcase vapors and if the oil is really dirty it can raise the emissions.

 

Just add a couple gallons of E85 to your tank. That will lower the NOx and the HC's as well without raising combustion temps. You are very close to the pass so I would just take the $10 fix and move on.

GD

 

E85, "dry gas", denatured alcohol, are all about the same thing chemically and will have the same effect. E85 is certainly the cheeeepest.

NOx emissions are mostly due to high compression; that raises the peak combustion temperature, and it can exceed the temp at which the nitrogen in the air begins to combust. Best way to combat it is to lower the combustion temps somehow, which of course alcohol does. That's also the purpose of EGR which is why getting it working right has such a yuuuuujjjjje effect on that.

For that matter, just retarding the timing (cranking the dist body) acoupla degrees as Fast mentions but in a different way, might do the trick. Depends on how close it is now to the lower limit around the "spec". They check it of course, and it can't be too terribly far off of that; doesn't have to be dead on *****, but it does have to be within some certain range. I don't know offhand what that is but if you have a degree or 2 to give it might be enough. Of course you can just put it back after they're done with it.

The oil change trick usually affects HC emissions the most. Can be quite dramatic if the oil is real dirty. Probably won't affect NOx noticeably though.

I'd try not to mess with the tune until I'd tried the simple obvious stuff.

From my days living in Carlsbad, I can DEFINITELY agree with the value of the emissions specs. California has an atmospheric situation that makes it uniquely susceptible to filth in the air. Sure, to some people they seem like a bunch of commies or *****, with all their rules and all that; but OTOH I remember trying to drive up the 15 to Ontario and then the 10 to Pasadena not too long after I moved out there, in April when the inversion problem is at its worst, and the air was SO THICK AND BROWN I couldn't even read the signs above the freeway. I felt like that scene in the Blues Brothers when the car "throws a rod" and they're trying to wipe the oil off the windshield. I recall at about the same time going up to the Mt Palomar telescope with my son, and looking down from that fire memorial for the Pueblo tribe member that was killed some years back fighting a wildfire up there, and could hardly even see LA because all it was, was a big glop of brown soup with a skyscraper or 2 poking up through it. It's not ever anywhere near as bad as that whenever I go back out there nowadays.

 

You can move the timing 2 degrees either way from stock, but more than that, they will not allow. I used to tape shut 2-3 bleeder holes on the underside (arrow) with small pieces of masking tape. This made the valve to open more, allowing more exhaust into the mixture. Dirty little trick, but it seemed to help.

 

 

No problem...Pulled that straight out of a Federal vs CA chip comparsion years ago. Worked well for me trying to lower my NOx.

NOx formation is greatly reduced with retarded timing and a slightly richer mixture. Used to unplug vacuum advance on that van when it had a carb before the smog test and open the idle mixture screws about 1/2 turn. Idled and ran like crap at part-throttle but blew clean and they did not test idle emissions.

 

1 quart of denatured alcohol in the fuel tank always did the trick for me.
I would drive past the test center to the dead end turn around at the end of the road, pour the DN alcohol in the tank, then shake it all up by swerving left and right on the way back. By the time they actually stuck the probe in the pipe, I was good to go. In my experience, using the DN alcohol made the CO numbers go to ZERO. I have always found that HC and CO worked like a seesaw - lean the mixture (lower HC) and CO would go up, and vice-versa. The DN alcohol took the CO right out of the equation. Back then, they didn't test for NOx.

 

These are incredible numbers for a modified engine.

 

What a somewhat fresh engine, flow matched injectors, newer heavy loaded cats, and good tuning will do. i had also modified the wiring harness to use a newer style 4-wire heated 02 sensor with the signal ground straight to the PCM.

 

LOL, I used to dump about one extra gallon of fuel alcohol in the tank when I had to go pass emissions test. it worked.

Now all the stores (Home Depot, Lowes) no longer sell alcohol! Why?

 

Around here they sell denatured alcohol in the paint idle. But E85 is a lot cheaper and there's a lot of stations with it in California from what I understand. Basically the same thing just 85 percent alcohol instead of 100%. But the other 15% is gasoline so you just use 15% more of it. E85 is super cheap like $4 a gallon.....

GD

 

4 dollars a gallon?? It's 2 dollars here...

 

Yeah it's probably more like $3. I don't live in the soviet socialist republic of California though so I'm not sure. The Thunderbolt E85 I sell for dyno purposes is more expensive than pump grade because it's tested to be exactly E85. Pump grade E85 is often as low as E60.

GD

 

Yeah. So far, they've got us paying to save everyones collective butts!

 

Update:

Here is the first run back in November- rebuilt near-OEM L98 B2T (mild cam) with old walker CAT. Timing 8deg BTDC.



Same with 2 gallons of E85 in about 10 gallons of 93 octane yesterday. I need to say that this was a different machine. My first guy's machine broke and it has not yet been repaired.



Interesting how the E85 did double the measured HC (still fine) but nothing for the NO.

I think my old aftermarket cat is suspicious. It's been through quite a bit. I ordered a new Walker 81124 and will have it installed next week and report back.

I am also going to take a deep dive to make sure my EGR system is working 100%.

 

Retarding the timing a little bit should bring the NOX down just enough to pass. HC and CO will come up a little bit, but should stay below the limits. You said you are at 8BTDC. Stock spec is 6BTDC and it was mentioned that CA allows 2 degrees up or down, so if that's true, set it at 4BTDC and try again.

 

Thanks I will do that as well.

 

See what I said, CO goes to ZERO with the addition of denatured alcohol.

 

But I'm failing on NOx. And those results are so clean it makes me wonder if your smog guy knew the difference between a tailpipe and a hitch receiver.

 

Why the difference in RPMs from the first test. Did the tech leave it in 2nd gear the first time? Would the lower rpms make nox rise?

 

I guess this stuff doesn't work in California.

 

I sued that more than once, it seems to have worked just well enough.

 

I'm sure you know the federal government does not set California's emission standards.

 

Holy grail recovered! Passed CA smog with flying colors.

Put in a new Walker CalCat which didn't help.

Replaced EGR valve, checked EGR valve solenoid, replaced EGR sensor, replaced vacuum lines - Passed.

I studied the EGR valve itself a lot. It is a sensitive valve which is why it is so expensive. What makes it sensitive is the "negative backpressure" disabling feature. All it means is is that if there is no or too little exhaust backpressure, any valve diaphragm vacuum is vented and the valve will not actuate (remain closed, no EGR). This is purely a failsafe for a stuck solenoid and idle conditions. That is why for those setups that have very little backpressure at the CA test load conditions, a proper functioning valve may not function.

It was invaluable for my tech to have a vacuum gauge watching the vacuum on the solenoid. This watched whether the valve was open or closed.

What my tech found was that in the upper range of the acceptable RPM/load test range, he could see the EGR valve was open. On the low end of the range, he could see it closing. All he did was run that portion of the test in the upper range and it passed.

Dumb but critical.

Thanks for all the help here.