Thread: SR20VE with AIV

I am trying to pass MD state emissions testing with my VE in a 1993 Classic(SR20VE with JWT bin loaded on a Calum ECU, SR16 VE cams, CAI, and Fuji, 2.5" exhaust, etc.)

Bottom line: I need to reduce HCs by about 30% -- the other pollutants monitored on the roller dyno test are within acceptable limits. I've tried a bunch of stuff that has not helped, and failed my 7th test yesterday. Happy holidays!

I've read that injecting air into the exhaust can reduce HC emissions. So I have temporaily replaced my Fuji with an old HS header that has an AIV fitting on it. I also added an Air Injection Valve and hooked up the vacuum hose to an AIV solenoid, which I plugged into the harness where the old AIV solenoid used to be. Fabulous looking in a Frankenstein sort of way, but it doesn't work.

I think that my current problem is that the JWT bin is not activating the AIV like it should. I have 2 questions:

1. Does anyone know how to modify the bin file to turn on the AIV? I can make changes and burn new chips for the Calum ECU with no problem -- I just need to know what to change.
2. If I just connect the vacuum hose from the AIV directly to the intake the AIV will operate all the time. Are there any issues with running the car like this for testing purposes? For example, I would prefer not to melt the cat or cause other unforseen problems like backfires, engine fires, etc.
   

Thanks much for your advice, it always appreciated and respected.

Bill

I have seen several SR20VE motors pass emissions in the older cars with ease WITHOUT the AIV. If your hydrocarbons are very high but your CO% is very low, then you have a slight missfire and or are running lean. If your CO% is low then you are not running rich. Check your idle fuel adjustment, plug wires, ignition timing, maybe even fuel pressure.

-Ted

Ted --

Thanks for your response. Actual test results are available here:http://www.sr20-forum.com/vvl/9162-maryland-emissions.html

The car gives 14.7 AFR at idle and at steady throttle. Note the lower HC emissions at the end of the test when the throttle is pretty steady. Fuel pressure is stock and I had to work with JWT on this tune because the standard VE tune that they sent me first off ran way too lean.

I've messed with timing, swapped the cat to a factory OEM cat, tried a leaner tune, swapped in new iridium plugs, and even tried running 40% E85. Nothing really has helped, and running leaner hurt a little. Looking at the test results, there seems to be something associated with acceleration that is causing the HCs to increase.

The reason that I switched to a VE was so that I would be able to sail through emissions testing. The road to hell is paved with good intentions.

Bill

Why dont you get a stock ecu along with the injectors/ MAF and whatnot. Would be alot easier than tryign to rig something to fix your problem. If you need I can probably find you the parts for cheap.

BillC

If you are at 14.7:1 A/F at idle, then that is too lean. Most vehicles run the cleanest at about 13.8-14.1 A/F. You are most likely too lean still.

Also, Get rid of the Iridium spark plugs and go to BKR6E or BKR7E plugs and mess with the spark plug gap a little. I'm not sure what you are at now, but try .032-.035" gap.

Most people see HC and the relate that to being too rich. HC's are partially burned hydrocarbons and CO is raw fuel. If you are miss firing slightly and or your flame front is running out before the end of the cylinder bore, you will have higher HC's but low CO.

Hmmm, I thought that the whole purpose of the O2 sensor and the closed loop system was to drive the AFR to 14.7 at idle and under light throttle applications. That's certainly what I see in a stock B13 with a factory ECU. What am I not understanding?

I have tested 7 times. For the last test I used BKR6IX (Iridiums) gapped at .034, for the first 6 tests, I used BKR6E-N plugs gapped at .036. If I go back to the BK6's would you recommend a smaller gap?

I've posted a summary of the data from all 7 tests here SR20 Community Forum - The Dash
The CO values are not particularly low, but they are within allowable limits. If you have a minute, take a look at the data and let me know what you think.

Thanks very much.

Bill

Is failing MD emissions a common thing with OBDI VE swaps? I don't think I'm due until November, but I'd prefer not to fail when the time comes.

Maryland's emission test is the standard dyno/tail pipe monitoring system that many states use. Some VEs pass this test easily and, apparently, others have issues. I have not yet figured out why some pass and some fail. Since emissions are so closely linked to fuel mixture, I have to believe that the ECU is going to have a big influence on whether a car passes. The whole test occurs at engine speeds under 4000 RPM -- part of the fuel map that we don't pay a lot of attention to, and certainly do not tune for emissions purposes.

I have not yet tested with the AIV activated, so I do not know whether this would be helpful.

BTW -- does anyone have any input on my original 2 questions?

1. What can you change in the BIN file to activate he AIV?
2. Are there any dire consequences of temporarily running a car for for for test purposes with the AIV open all the time?
   

Good luck with your emissions testing -- let us know how it goes.

Bill

mine didnt pass.... lol

UPDATE

My long automotive nightmare has ended. I passed the MD emissions test on my 10th attempt. I want to thank DC Scotty for originally suggesting that I try air injection.

After testing a couple of other things, like Calum's VE tune instead of JWT's and richening up my light throttle mixtures, I finally tested with the IAV installed and working. Here are the setup details:

- Back to original JWT tune from my first test.
- AIV from 1991 SE-R retrofitted to VE using an early HS header that I had in the basement.
- Installed my old copper plugs NGK BKR6E-N gapped at 0.034" and took out the Iridium plugs.
- Timing set at 12* BTDC (normally at 15*)

I connected the AIV vacuum tube (which originally comes from a solenoid and allows the ECU to activate the AIV under certain conditions) directly to a fitting on the intake manifold on the engine side of the throttle body. So the AIV was activated all the time. This did not cause drivability problems or backfires. However, I did not run the car this way for extended periods of time -- just for testing. The lower hose from the AIV was attached to the brass tubing from the header, and I routed the top AIV hose through the little black noise reduction box and then over by the battery where I secured it with a cable tie and affixed a little filter to it. The AIV itself was attached to the head near it's normal position by a single brave bolt.

Here are the results of the emissions test:

..................State Limit..........W/O AIV.............With AIV
HC..................1.0....................1.6....................0.8
CO................20.0..................16.8...................11.9
NOX................2.2...................1.8.....................1.2

I test again in 14 months, but now I have a better idea of how to pass.

Thanks to everyone who tried to help.

Billc