Please help me diagnose what is wrong with my car so i can get my registration sticker,
the local smog shops in orange county wants me to slip them more than just a "$20" to pass, try $300 . I have not followed through with the actual test because the smog guy said it wont pass for sure. I have a 1994 ls with a jdm gsr motor. I've
researched all the threads on HT but i can't conclude what is wrong with the
car. I have not tuned the car since I installed the motor, just timing belt, water
pump, and new stock spark plugs. No CEL, virgin usdm p72 ecu running on 91 octance gasoline.



Here are the results i got with my car running for an hour before the test. I don't think i have a bad catalytic converter because only the NO is high and CO and CO2 are within limits. I have the evap system connected and plugged up to the purge solenoid if that makes any different. Research on HT tells that high NOx means high combustion chamber temperature and that i should run seafoam, change to colder sparks, clean EGR system(which doesn't apply to me). My concern is that hydrocarbon levels are high and that NOx is high so somewhere in a thread that i read, someone said that it might be the unburnt fuel burning up on the cat and then causing high NOx as well which makes sense and i suppose that would mean i am running rich?

Another reason that i think my cat isn't defective is because i passed on the same cat when my ls motor was in the car with the results below. Since the last smog i haven't put 10,000 on that same catalytic converter.



My gsr header doesn't bolt up to the flanges on the stock ls cat and the smog technician says that it is okay because i have no o2 sensor at the cat, this was actually why he wanted to run a pretest on the car to see if it would even register on his machine. I am also using the original fuel filter on the car. Im real busy with school so i haven't had the time to tune the motor, it wastes a lot of gas, i get about 22mpg when i drive around the city, this is keeping the car below 3000rpm and never seeing vtec. It will get a valve adjustment as soon as i have the ends or time to do it. I bought the motor from Hmotorsonline and steve over there says there is about 30,000 miles on the block. I love this car and it have recovered it twice due to theft, im keeping it forever. I don't usually post on here for help but I am all out of ideas and i need my registration sticker for next month. There's a lot of techs here on HT so if you come across my post, please give me an input of what you think will resolve this problem. I purchased a bottle of seafoam and im going to run that through, i also got g2p but thats probably going back to the store because it looks like a waste of money.

 

i have a 92 hatch with a P28 chipped running my f23a1.. and i did not pass the first time... i found a virgin P06 ECU and passed with no problem.

i passed with
HC in PPM Loaded was 91 the standard is 220
HC in PPM Idle was 126 the standard is 220
CO in % Loaded was 0.19 the standard is 1.20
CO in % Idle was 0.09 the standard is 1.20

so i saw just get the stock P06 ECU and try that

 

I really doubt the ecu will make a difference with the readings because I am using the stock usdm gsr p72 ecu. I have every us emission parts that I know of on the car. Please help ht! I'm running out of time.

 

well it worked for me... can not hurt to try... the ECU will give it less gas.. anyway good luck... if you try the ECU let me know how it worked

 

It sure wouldn't hurt to try but I don't have the funds to go buy a new ecu. Given the fact if the ecu does not work. It is most likely I wouldn't be able to return it and get my money back. Thanks for the advice ill stay open to that. Anymore ideas 2.3lcivic ?

 

well i dont know where your from but if you were in AZ i would let you use the one i have..... well if you would like you can rent the one i have... paypal me $60 i will send you the one i have when your done send it back and i will paypal you back your money... If you want to do that just PM me

 

hey HT members, i have a theory for why my car wont pass emissions. Maybe my catalytic converter has to be bolted up to the header securely to warm up the catalytic converter to operating temperature, that would mean that when i was testing, the gap around the flanges would cause air to flow in as the downpipe is pushing exhaust fumes through and cause a cooling affect not allowing the optimal operating temp for the cat to be fully functional. What do you guys think of that? im reading that o2 level should be 0.0 when the cat is fully heated. Your input is greatly appreciated. Im going to buy the donut for the downpipe and then have a muffler shop cut and reweld the B pipe so the flanges line up correctly tomorrow, ill keep this postt updated as what my test results are tomorrow.

 

i just let a friend who has a 92 hatch use the P06 ECU on his lsvtech motor and he passed... so i would say that is an easy fix

 

that is true, when the cat is hot enough it will show reading of 0% oxygen, most likely its a prob wit the cat and make sure u have the car running for a while b4 u take it to the check to make sure ur cat is heated enough for the smog check

 

ok, i just went under the car to look at the header to cat connection, even though my header and cat flanges do not line up, it is very secure and there is no gap for an exhaust leak. there goes my hope for passing smog tomorrow. = /. p06 ecu huh? maybe ill do that, i really want my car to pass smog with my current set up though. would you say the emissions readings are an indicator of how well your car is tuned? perhaps if my NOx and HC levels were within range my car would be performing at its optimal performance, high nox = high combustion temperature so how good bad of a thing can that be?

 

OK, alot of good info from you.

You have noticed the O2 reading already from both tests. And you made a correct assumption.

Your old test shows that the cat was starting to fail you. A cat in good condition will be at 0.0 at the 25mph part.

Your gas mileage is a concern to me also. O2 sensor is a normal cause.

So from here I would say that either your cat is gone or you have an exhaust leak. A exhaust leak before the O2 sensor could also be a problem. Or just the O2 sensor.

Straighten these out and you should pass with flying colors because it is not far off really.