My car won't pass the local smog tests. I have to put the car on the dyno for smog tests here in illinois. My first test my HC were supposed to be 0.80 and they were 0.88 and my CO was supposed to be 15 and were 21.1 that was in feb at 40deg outside temp. then i put a whole new exhaust system in( see sig) and replaced a bad TPS and EGR soleniod. I retested last weekend in 70 deg outside temp. I adjusted my fan to turn on at 260 deg so the car would be nice and hot, it ran about 230 during the test. rased the tire pressures and changed the oil right before the test. Now my HC are 1.67 and my CO is 8.2. How can i get my HC down to pass? Im out of time as I'm supposed to have this done by the end of May. Please any Ideas would help me out if this doesn't pass I'll have to put about $700 into it or more to convert from TBI to TPI. I don't want to do this BC I'm expecting my first at the end of the year or beginning of next so money is really tight right now as we begin to buy the things we will need. Please help me !!!

 

there is a lot that can be done to pass smog. with a new cat it should have passed on the HC's but i would guess really bad tuning. first put new plugs, cap, wires, etc. (basic tuneup). also use a really thick oil if your going to be running the car that hot. probably 20W-50. have the tbi unit tuned out and it should pass. therer is also those pass emmisions in a bottle dealies, dry gas, and alcohol.

 

gimme a little credit here. a tune up is basic. I did that when i first got the car last year and inspected every thing before the test. (ACDelco Rapidfires,ACCEL cap and rotor and 8.8 spiralcore Super Stock Wires) Timing is set at 6 deg. with the wire unplugged. what exacttly do you mean when you say "have the TBI tuned out" if you mean adjust the fuel pressure i can't BC i put the original unmodified TBI unit back on for the test.

 

The only things that I might try is a new O2 sensor and new oil in the cranckcase.

IIRC, high HC is a sign of a weak converter, but you're running a new one. It might not be getting hot enough. I have to pass emissions tests on rollers too and I have a weak converter. The SLP headers don't hold in enough heat to keep the converter hot.

I think an O2 sensor would help in your case.

 

well lets see for the tbi unit, the injectors can be messed up...i think the air/fuel ratio can be adjusted. not sure i run a carb. for the timing, retard it as far as it will go with the car still running. if you think your numbers are bad try mine the first time i had to get it smogged. the CO is supposed to be less than 1%. mine was at 11%. the rest of the numbers were like that also. try alcohol in the fuel...

 

also, depending on how old the cat is...they dont reach there full potential until about 1 month of driving. people say that they make such a difference brand new because it shows how bad there old one was.

 

My O2 sensor was changed when I first got the car. Let me expalin a little about myself. Whenever I buy a new(used ) car i go through everything to make sure it is in top running order. my tune ups usually cost $400-500 depending on what type of vehicale i get. So the o2 is less then a year old. Also the cat is a little more than a month old.And I changed the oil just before i went for my last test. The air/fuel ratio is handled buy the computer in my car so to tune it i would have to change the chip out I think EFI guys help out here. I tried to burn a new chip but for some reson I cannot seem to get it right. But you are saying retard the timing as much as possible. What effect will this have on the HC? Im told that HC is a sign that im running rich or not burning all the gas. Im running a Accel ignition so im pretty sure im burning all the gas. I know this is long and drawn out but if I dont pass Emmisions they suspend ny drivers licence not my plates. and the only other way i know of to get it to pass would be to switch to TPI at a cost of more than $700 ouch!!!!!!!!!!

 

$400-$500... wow... that's a lot of parts.

Well, HC means a misfire. You can get it by running rich or lean; if the ignition system's weak and/or the a/f mix isn't up to par, the car misfires. High HC + High CO usually mean your air filter is clogged; you're running rich. (Not enough O2 in the motor to create CO2). High HC by itself usually means running lean. Might as well throw in a new cheap-o air filter for $6, couldn't hurt. If you pass, put it back in the box for next year.

You might want to try one of those off-the-shelf "emissions pass" additives. I've run Guaranteed To Pass a few times, and I passed...

Make sure the outer ring of your balancer hasn't slipped, and is throwing off your timing. Bring #1 up to TDC of the compression stroke, and make sure the timing mark lines up with 0 degrees advanced on the timing tab.

For kicks, just go over the simple stuff. Make sure the distributor cap & rotor contacts are free of carbon tracking. Make sure the plug wires test out okay with an ohm meter. Make sure the plugs are clean and gapped to spec, and haven't loosened up somehow in their holes. If you have Accel u-grooves, make sure the brass terminal on the end of them (which the spark plug wire clips to) isn't loose. Double check to make sure there aren't any exhaust leaks that could be fooling the oxygen sensor. You said you put the original TBI back on the motor- how many miles are on that TBI? Could the injector be clogged, or stuck open and leaking somehow? Do you have a fuel pressure gauge to test it? Did you put on a heated oxy sensor or just a regular one? Do you know how to put the computer in field service mode to find out if you're driving in open loop or closed loop? (They have such a thing on TBI, don't they? Not sure...)

Are you getting just a sniff test done, or are they throwing you on a dyno (like I have to ride, in NJ)? Supposedly there's some old inspection station somewhere in NJ that I could go to, that doesn't have the new dyno test, and they just give you a regular 'ol sniff test. But I've passed the ASE 5015 test every time, so I haven't had to hunt 'em down.

 

well tomp hit it good. you shouldnt need to swap to tpi to pass emissions. if it were me i would check the injectors first since no adjustments can really be done to the air/fuel mix. people always think that they can just lean out a carb and pass. bunch of ny friends tyr it at school. however they still fail. the backfire gives the sniffer a "false" reading and can really make the numbers sore. however you are very close to passing. check the injectors and the pass emmissions in a bottle.

 

vette9190,
I am not a TBI guru by any means but I have done engine rebuilds on a 91 TBI Camaro and a 91 TBI Firebird, when I timed these cars I would swear that the factory stickers said 0 degrees and not 6. But California could be different. Another possibility is when you replaced the TPS did you check to see if it was putting out the correct voltage at Idle? If not that could be the problem by itself.
Good Luck!

 

TomP I do have to run on a dyno here in illinois too. Well im running a K&N fillter open element. and an Accel ignition, infact if anything I would think I'd be running lean, but I hooked up my laptop lastnight and ran winaldl( now that I have a power inverter to get AC in the car BC my laptop battery sucks and wont hold a charge) I'm getting a RICH flag coming up alot and my low RPM BLMs are in the 110-118 range. I looked at the printout from the test facilty and it appears that my problem is at low RPM. They test the car by simulateing a drive for 2 min. going from 0-15 then easing down then back up to 35 then they stop then accel up to 45 then slow to 20 and back up to 60 then stop. my hc are up at the lowest speeds which is of a concern BC i have a multi strike ignition it should be burning just as well below 3000 RPM BC of the multi strike capabilty I would think. When I get home I may post my O2 and BLM charts so people can see. I have another set of wires that i will try, but I dont think that wires would go bad after the just 10000 miles I have put on since I bought the car last year. Oh I also retimed it. The sticker does say ) deg but w/ the ignition it say retard it 4 deg and then tune from there. I had i set at 5 deg but reset it to 12 last night it is now at 35 w/computer at idle. I also checked my TPS winaldl gives you a readout of the sensor output so it make adj easier.Oh and I do run in closed loop mode after it warms up(winaldl has a closed loop flag) I am going to get a bottle of the pass emmision stuff and try again tommorow. I can pay $20 to test without it counting so i can see if i will pass or not then retest if i can. so as much input as possible before tommorow would be great.

 

Checked your fuel pressure lately? Any exhaust leaks in front of the O² or problems with the A.I.R. system? Still using the stock EPROM?

Better get is plenty warm today...

 

Hmmm, i just set the timing on an L05 caprice and the base was 0*, I thought the L03 was 0* too...........

 

Use the lowest octane fuel your engine can live on... the lower the octane, the more completely the fuel will burn, which makes for lower emmitions. I'd say put a little alcohol in too, like what was said before.

 

I didnt teat this weekend. I didnt have time, and i wanted to run that pass emminsions stuff through my car. It said to run a full tank through the car w/that stuff in it first. so I will do that and maybe next week end see if I can test it. I thought I have heard people say to run the higher octane gas through for tests, but i will try this.I have the timing knock back 12deg intial now so it will run on the cheapest gas we can get around here 87 octane. nalso the timing tag does say 0 deg the computer is supposed to handle all the timing and set its own at 13 deg that is why i have 35deg at idle now should i leave it at the 12 deg base i set it at or put it at 0 deg and let the comp do everything. I dont know how to check fuel pressure on this engine BC there is no schrader vavle to hook up a gadge to but i watched the spay pattern out of the nozzles and it seemed llike a good spray pattern. I just replaced the exhaust a month and a half ago , I have recheck for leaks twice now but havent found any.And yes i still have the stock chip. i tried to burn a new one that would take out some fuel BC it is way to rich, but have had no luck. the chips causes the check engine light to come on.Man this stuff is starting to **** me off. Its actually funny BC if i cant get this fixed by august ill have to get another vehicle and since im broke it will be a cheap POS that will polute more than this one so they are actually making things worse instead of better.

 

trust me by august you can have it smogged.

 

i feel for you i really do cause nomatter what i do as well i cannot pass emissions in the iroc either. I am always a little under the state standars with all new parts (accel cap and rotor) ect new hoses tuneup 02 sensor EGR ect. I qualify for a waiver cause my car is an 85, if i spend 250 dollars or more on repairs ill get a 2 year sticker. check your states inspection laws to see if you qualify as well since your car is over 10 years old

 

i thought fuel injection was easier to pass with. it took me my friends shop and 2 hours with the timing light and carb adjustering tool to pass.

however it took me 5 hours to get it back to how i like it to run....damn smog check.