Well I went out to get my emissions done the other day and failed. I didnt fail too badly, but I'm not sure about what to do to make her pass. Right now I'm running a HSR with no AIR or EGR. Everything is else is pretty much stock except for the 24lb injectors and the LT1 cam. Limit : Readings Hydrocarbons =1.00 : 1.01 FAIL Carbon Mono = 20 : 5.63 PASS Oxides of Nx = 2.2 : 2.93 FAIL I'm going to check my plugs and change my fuel filter for the next run. Right now I have my fuel tables and timing tables adjusted. The changes are very minor, but I think I'm going to throw back in my stock BIN and change the injector constant to 24lb hr. Then take it out and get a couple of scans. I'm assuming that leaning it out will help more than richening the mixture???? I'm pretty sure my cats are ok, but they are about 2.5 years old. I know that Trax did this a while ago with forcing open loop.....but when he was going through his test they were not putting him on the rollers. Not only that but he had failed miserably the first couple of times. Any input is appreciated......I will also keep this post up to date as I make changes and go through the tests again.

Trust me, all that you need to do is take about 10° of timing out, and it'll pass with flying colors. It'll both reduce HC and NOx, and since you were close on both, it's the PERFECT thing to do. Then, when done, just add it back in. I do a lot of work with emissions and this one is a slam dunk. The later timing will reduce NOx by reducing peak combustion temperature, and the HCs always go down with less timing, by having the ignition start at closer to TDC which means it's compressed more at the time of ignition reducing misfires, and the later burning also brings up exhaust temperatures which will get the cat working better, and the burning process isn't fighting its way into quench areas, and isn't fighting cylinder compression as much which gives a slower controlled more complete burn. Yes, it'll lose a little power, but only temporarily.

Good Luck

Red,
So would you just grab your SA tables and knock em' down by 10* or just twist the cap? I think either way it will work....sounds like a "whatever is the easiest".

Thanks, I will be sure to back down the timing a few notches before heading back. I'll be sure to update you!

For better drivability, just burn a chip that has timing removed in the areas of the test, and leave idle and WOT normal. To me the chip is easier, because of the distributor lock down bolt being a pain.
Good Luck.

Havent forgot about this...:-) I got some extensions for my emissions...looks like I'll be heading back late this week...I'll let ya guys know how it goes!

Please do!!! We'll need to know what you've changed, as well.

Was plannin' on it! Looks like it's not going to happen this week...will have to wait till next! Had some snow up here in Maryland area...fbody dont go in snow :-)

Back in the old days (about 10 - 12 years ago) My IROC never used to pass emissions. Eventually, I stubled upon disconnecting the EST connector and setting the timing to about 1 degree BTDC. Worked like a charm every time. Of course the car barely ran under its own power but hey who cares!

Emissions tests were stopped years ago here.

How can you expect to be able to pass just by reducing the timing? The smog center's test equipment checks to see what the timing is set at. They won't allow you to even perform the test if the timing is not set a the stock value....

The testing in Miami stopped in 1995 or so. None of those checks were performed here. Back then, the hood was never opened. They would just stick a probe up the tailpipe and take a reading. In some instances (but not always), they would run the car on the rollers. They would slide a mirror to check for the presence of a cat, and they would make sure you had a gas cap. That was the extent of the test. I apparently would be S.O.L. with today's tests.

One question: do they visually check to see where base timing is set, do they plug into the ALDL? How does it work these days?

It all depends on where you are. Here in Dallas, TX area, we run on the rollers, 15 and 25 MPH, with a sniffer up the exhaust and a sensor on the hood to pick up the RPM level. No timing checks, nothing olugged into the ALDL on an OBD1 system. They do plug into the ALDL on new cars though, and a lot of them I don't believe ever go on the rollers.....

In california they open the hood and check base timing. If it's wrong, they give the the option of failing, or paying them $15 to adjust it for you. I suspect that +- 1 deg. of spec. is ok.

1* +\- is all that is allowable in California on the timing. They also check the vacuum lines and the codes on the computer. You would have to back off the timing in the chip (Thank you Prominator) to fool them...... I get to try this in December.....

In MD they check your gas cap...use a mirror to make sure you have cats then throw you up on the rollers. Once your on the rollers they drive through the gears and cruise a little bit w/ the sniffer on your pipes....that's about it!

Well I finally went back....All I did was take 4 to 5 degrees timing out of my main spark advance table and all I can say is that it was worse than the first time I took it in.

Readings:
HC: 1.04 FAIL
CO: 6.21

From the graphs they printed out it looks as if between 20 to 45 mph is where I'm failing. I guess I'll have to do a little driving around at those speeds and get everything tuned up properly.

I havent been driving it much, so I think I'm going to freshen everything up (fuel filter, plugs, new coil (using one from an old V6 blazer cause I blew my MSD up), and maybe some new plug wires ) then take it back and run it lean and hot...obviously not to the point I fry the motor, but with what I can get away with!

Question, if I take timing out, should I have taken fuel out? Seems to have smelled a little rich when the timing as reduced?

Is your O2 sensor working? Dropping the timing should have let the O2 correct it back to stoich if you drove it a bit and let it "learn" before going in for the test. Exhaust should not have smelled rich.

Well I drove it for about 15 to 20 mins before I got to the station w/ the reduced timing...that long enough!

And they didn't give you a NOx reading like last time?
Replace o2 sensor and put on a fresh cat.
Does your motor burn any oil? Replace your PCV valve and see how she does. A new cat does wonders.

Most likely - no where close.

Try resetting the computer (pull the negative abttery cable off for a few minutes, and then drive it with the reduced timing for 50 - 60 miles with only moderate acceleration to "learn" the new set-up.

It takes a computer only a few instances to "learn". The most important thing is that you've got the motor up to temp (stat's opened) and have driven around for a good 5-10 minutes with it up to temp. The hardest part to deal with is the ecm's that hold the BLMs on key off. The 8746 resets all cells to 128 which is really nice when you are tuning, not so nice when you don't have the ability to retune the calibration.

But isn't he running a 7730 ecm on a 91 GTA? I has a corporate GM tech tell me it took 50-75 miles of driving for a good re-learn on my 7730. Then again, he was an old phart like me and could have been stretching the requirements a bit....

Doesn't take nearly that long. I can get a tune with the BLMs in all in the upper 120's within 5 minutes of driving down the road with 4 or 5 accelerations and once cruising stretch. I hold 2nd gear and roll into it slowely up to about 60mph on 1 of the accelerations, other than that you just need a warmed up engine for it to "learn". Even the "learning" doesn't last, it's always learning, be it short term or long term, the long term learns VERY fast on a human time scale.

Hmmmm.... good info to know - THANKS!

Well I drove about 15 mins to the station, and it was up to temp...was running at about 179*.

HC: 1.04
CO: 6.21
NOX: 2.2 (Passed this time)

I know that fresh cats can really make a difference but I'm trying to avoid doing that. The 02 is only 6 months old, and yes the motor does burn oil...so I will grab a new PCV valve and try to get it a little better tuned.

Which reading is affected if an engine burns oil?

ftp information:
IP = 69.174.156.111
UN = 3rdgen
PW = 3rdgen

There are 3 files there *02.csv (dump of datamaster data) *02.bin (the bin that was used) and for those with datamaster *02.uni

Feel free to give a look see and provide feedback!

TIA!

poorboy8-I live just north of you in MD...keep everyone updated on your progress,I want to do a mini-ram set-up down the road and have been looking for examples of people who can pass
emissions (especially MD's) with no EGR. I remember traxion did it while removing lots of timing too...you said the exhaust smelled rich? That may have affected it. You said it burns a little oil? Is that the classic start-up puff of smoke..or do you stilll burn oil after driving it for a while? New cats help alot...I wonder if the AIR disconnected hurts any?

FYI...this info is still there and availible...if you want to take a look at it and are having problems drop me an email.... poorboy08@gmail.com

Not a problem I have all intensions of keeping this thread up to date.

Another question though, would it be safe to say that less fuel equals less emissions?

I guess it matters how your adding the fuel...see I have a FPR bumped to around 47psi... but only a stock chip. I know its not the 'correct way" but its only a bolt on 305 TPi that actually runs pretty good so I have no real need for a custom prom at this point.I pass MD emissions by setting timing to stock and setting fuel pressure to stock.But I also have EGR /AIR ...ect..

I have read that by just turning up the fuel pressure, it is only effected at wot....since the ECM controls the fuel ratio anyway.
Now if you actually alter the fuel curves in the prom...thats another story.
I 'm not very knowlegable of prom-tuning but if your running rich that un-burnt fuel will screw with your emissions. i would cut a chip that is backed off on timing and fuel for emissions only and see what happens..the car may be very weak but it will give the goverment what its looking for. You said you backed off timing 4-5 degrees what was it set at before that? Are your cats on all the time? I have a nice random tech cat that sits in the basement and goes on for 1 day every two years .....worse comes to worse new cats do help alot. Then when emissions is done just throw on straight pipes and the cat stays nice new and fresh...they do wear out over time..and if you have been running rich for awhile it really shortens there life span.

I'm getting ready to go thru emissions in Memphis. Last year I did not pass with stock chip. I've got the prominator this year so i'm looking to figure out some tuning......

I have stumbled upon this while surfing the web.....

http://www.lubedev.com/smartgas/additive.htm

Not only help with MPG but, may help on the emissions thing to..!!

What do you guys think....??

Interesting read.....

Curiousity makes me want to find out more about it and what effects acetone has. Nothing is for free remember?

Have a 92 saturn to experiment on if I can find any real info to back anthing up with.

Main point there is why has there been no miracle cure for gas mileage or wonder car, engine or fuel? I'm willing to bet someone out there knows or has done it.

Also believe if u read some of the ingredienets in multiple doferent additives some already use acetone. I'll check that when I go to the parts store next.

later
Jeremy

That's not true. Removing timing did not work. Alcohol did not work. Nothing worked except forcing OPEN LOOP and running a really high injector constant such that the motor ran REALLY lean. However, this is incredibly dangerous. I don't advise this to anyone ... however, if you are willing to accept the possibility of melting your motor then you can pass. I dropped my HC's down to 17ppm with a 230d duration camshaft.

Tim

Trax...your saying less fuel equals less emissions, and or would you agree? JOOC, in what way did you force open loop? I believe there is a delay option for going into closed loop, although I dont plan on doing it this way I'm still interested. Also this process of making the engine run lean can be acoomplished through the VE tables or am I missing something? I guess I'm trying to figure out why you forced open loop to make the engine run lean verses modifying your VE tables?

Tim,

You didn't run into a Lean Misfire issue?

Lean and you can misfire = really HIGH HC but what's more common is very high cylinder temps (lean burn) and the result is abnormally high NOx. Running lean at idle with a big duration cam isn't the same as one that's tight.
I recommend running slightly lean and at 200 degrees on the dot for engine temp. If that doesn't work, try a fresh cat and take out a couple degrees of timing to keep the exhaust hot.

Well the problem with running the car at 200* is that I have a 180 stat and they put a BIG OL' fan in front of the car...so I'm sure with the 180 Stat that I'm not getting much hotter than that. I am going to work on leaning it out a little bit...especially at low speeds...according to the graphs they sent that is where I'm failing...but when the car is at 50 to 60 mph it's clean as a whistle!

Sorry Traxion I thought I had read awhile back about you cutting back the timing,and getting results.
So your saying it is pretty much impossible to pass MD emissions without EGR and a big cam? You have SD...would MAF have made any diffrence?I want to do a Mini-ram combo ...but need examples that it can work(in MD).

BTW..why did you sell your IROC? I know it has been awhile, but wondered why,since you had a great example of a thirdgen's capabilities.

poorboy,

Illinois uses the same IM240 testing regimen as you have there.
My Xfire had previously passed the tests with flying colors when I had a
CompCams Extreme Marine Rlr 264/270 @ .006, .488/495 lift. 112d LCA. I was running 10.5 psi on stock injectors. But then I added TPIS headers, 1.6 ratio rockers 80# injectors. I continued to fail on the HC and it was usually during the Decel portion of the test. The HC would spike. When the dummy on the dyno would drive the car, he didn't know how to shift a manual and he'd blip the accelerator with no load and overrev the motor. At steady cruise, emissions were way below maximums. I never got it to pass. Had I had a WB like I do now, I think I could have datalogged the test and "fixed" the problems. As it is, I got "classic car" insurance(its not a daily driver) and have an exemption from the test.

Couple of comments for you.

That combo should be emission friendly pretty easily provided the tune is in check for it and no other mechanical/electrical problems.

Are all sensors in good working order? Are the MAT and coolant temp read the same in the morning(usually a good sign).

No vacuum leaks and good plugs/wires?

As far as things tuning wise, what type of throttle body are u using?

Is the IAC set properly? Did u change any IAC settings? The IAC pruposely holds the throttle open for a sec. when u let off to burn that last bit of fuel before the blades close. There was alot of discussion about this topic on the board. I set mine back to factpry spec when it is time for emissions. NW IN is IM-240 as well. Try checking all IAC related setitngs and consider experimenting with the ones you have changed if any.

Another thing to try is to play with are your AE settings. With your HSR on there, your requirements would be far different than the TPI would be. Have you changed any of these? Cranking them up one way or the other could drasticaly richen the mixture or going far too lean could cause a momentary lean miss as well. Also you said you have the Innovate unit, so doing some simple drive time and duplicating there tests on a backroad might prove you some insite.

Watch for the spikes in your wideband and go from there. If its possible send the wdeband info to whatever u use to datalog and see what is happening if you can duplicate the rich spike...

All I can think to babble about now.

Something is out iof whack, just finding it is a pia.

My hotcammed, vortec headed Formula ranc leaner thru emissions than my 98% stock GTA and had no EGR or AIR, etc.

later
Jeremy

Well i'm definately going rich every time I let out of the throttle and looking at the graphs that is where a lot of my "below standards" are popping up. I think I'm going to take her out for a 4 min. drive like the test does and try my best to mimic the mph with in the time frame...I'll log it and post it up.

Question if I up the inj. constant will this help to alleviate the rich condition on de-accel...or where would be the best place to work that issue for the test?

That's harder than you're making it sound. If you go too lean, you get a lean incomplete burn or misfire, and HCs shoot right back up to where they were before (or higher).

Maybe try bringing down some 20kPa VE values in the RPM range your over-run HC emissions are a problem.

That's one way, there are others . Make sure decel enlean is working and "tune" it for the test . Or go so far as being agressive with the DFCO settings. Then again there's always the ultra high throttle follower steps to prevent the RPM from changing too fast.