Thread: Maryland Emissions

Thanks, Keo, for the smaller images.

I have been failing the Maryland State emissions testing. We use roller dyno with tail pipe sampling.

My setup: B13 SR20VE, SR16 cams, DE TB and MAF, VE injectors, Fuji, after market low flow cat, CAI. I am running a JWT ECU program. Since the program JWT gave me originally was super lean, I worked with them to richen it up, and this custom program is what I am running at stock fuel pressures and 15* timing.

Summary data for 7 test so far are provided here: SR20 Community Forum - The Dash

Here are the results of the first test:

[img] http://www.sr20-forum.com/usergallery/2948b17493a49e7.jpg[/img]

For the second test, I set set the timing at 13* and changed the bin to a leaner version of the JWT program. This one gives me an AFR of 14 at 7000 RPM and shows little richening at low RPMs under load.




Any thoughts? I can adjust fuel pressure and timing. Also, I have a Calum ECU that I can run with a number of BIN options -- SR20VE, SR20VE with cams, SR20DE, etc.

Thanks for your help.

Bill

these should be somewhat smaller

what injectors are you running? and did you fulling warm up your car before you wen to the test?

also, you might want to look into round your O2. scotty did and pass the test!

put your timing back to where it was before, your Nox jumped a bit when you retarded it.


I'd keep it at 15-17* BTDC, maybe work with the fuel maps to lean it out a bit that way, and also check to make sure that your O2 sensor and Converter are in proper working order.

Run the car real hard for a while right before you take it to emissions, and then make sure it is up to temp when you test.

Keo -- I'm running VE injectors.

Thanks, Rob. The second bin was much leaner than the first, and I think that that's what caused the NOX to increase. Why would you recommend keeping the timing at 15 to 17? Isn't it generally the case that less advance reduces both NOX and HC?

Yes, I ran the car real hard before testing. It was plenty hot, and I got to pull it right in on both tests.

I think my O2 sensor is working fine because the AFR oscillates nicely around 14.7 when I'm at idle or in closed loop mode. Note the low HC emissions toward the end of the test where there is little throttle modulation -- I think this is in the closed loop part of the fuel map.

Now note the high HCs early in the test even though vehicle speed is lower. I believe that these portions of the test are at 2000 to 3500 RPM in second and third. So I'm wondering what might increase HC under these conditions. If I can reduce these peaks, I will pass the test.

Thanks again for your help.

Bill

I recommended keeping the timing at 15* because that is what the ECU was tuned for in the first place. I think the problem will be solved elsewhere. Usually retarding the timing will reduce NOx and HC, but in your case it did the opposite that it should with retarded timing and leaner mixture.

I rolled back the timing to 13deg, lowered my idle to 600, and also put the AIV back on (to add fresh air into the exhaust). Bill, I had Calum's ECU with the bin very similar to your DE v4 bin file. Car idled like crap but passed emissions. I changed it back when I got home from testing.
I would install the Calum ECU with the v4 bin file and retest smog with lower timing & idle.

BTW, Both your O2 sensor and knock sensor signals are being ignored by the Calum ECU v4 bin.
(although they will still trigger a CEL if missing or bad)
So, lowering the timing or leaning out the maps is the best way to change the sniff levels.
On some of the later bins, Calum actually turns off these sensors within the bin.

Another thing, Calum recommends setting the base timing to 15deg as the ECU maps aggressively increases your timing. But by setting a lower base timing, you are also actually lowering Calums ECU timing advances too (as the RPMs will be lower & you will be running in lower regions of the map).

Did you ever install TunerPro? Easier to see, modify & compare these settings in bin files.

try sum dry gas, check ur spark plugs, and change the oil b4 going back. it lowers emmisions trust me i had a hard time getting mines to pass ct emmisions.

Thanks for the explanation, Rob. I agree that the problem will likely be solved elsewhere, and not only by pulling a couple of degrees of timing.

CRAP -- I had a typo in my first post. This is my VE, not my DE engine -- I've made the correction in the post (easier than swapping motors). Sorry for the misleading error, Scotty.

I'm now running a custom JWT tune for my VE and this one has the O2 sensor closed loop active. I have a Calum basic ECU in the car running this bin, and I also have the Calum VE programs, which I can easily switch to. But I'm trying to cut down on the number of blind trial and error tests that I make so that I don't end up playing poker on Wednesday nights with the guy working at the testing station. Anybody know of a service station in the DC/MD area that can actually simulate the MVA test for test and tune?

In response to your question, I've looked at TunerPro but have not had time to make the switch from ROM Editor. I'm still more comfortable with ROM Editor, and also with Windows 3.11, my favorite operating system. Something about old dogs and new tricks.

Thanks for the input, Scotty. I've been out of town, are you still looking to do some AFR testing? If so, send me a pm and we can schedule something. Also, FYI, I finally got back to my gauges/Lock Tite train wreck, and all is resolved.

Take care.

Bill

I've heard about the oil change thing before and actually did change the oil before the second test. I also checked the plugs but a new set couldn't hurt. Thanks for the suggestions.

Bill