thanks alot for the advise. the idea about a leak at the flanges right above the o2's makes sense. I didn't take off my y pipe to change out the o2 sensors but right before i changed them i had my intermediary pipe replaced because my gf convinced my that a road that we needed to drive on to get to this party was a short very flat dirt road. it turned out not be. i ripped a hole in my intermediary pipe on a rock sticking out of the road. my y pipe and the bottom half of my headers r pretty rusty and i bet that all the banging around caused a leak. i remember hearing exaust leak type sounds even after i got the pipe replaced but chalked it up to leaks caused by the new welds right after the cat. i know its real hard to get a good weld on rusted metal.

i know that the high school in my town has a fuel pressure tester kit i could use and plan on checking what it is. they also have a scanner. i know it will tell me if i have any trouble codes and can moniter different readings but i don't really know what to look for. i'm gonna have to dig through alot of post and stuff to figure that whole thing out.

according to this cats help to get rid of hydrocarbons. mabye it's is my cat? is there any way i can tell?

 

Ask a shop if they can test your car and get readings before the Cat and after the Cat. If I remember correctly, you subtract both readings and thats get your reduction result. Use that reduction amount and divide it by the "before Cat" reading and to get the percentage multiply by 100, which equals % of how well your Cat is flowing.

 

checked out headers for exaust leaks as well as the flanged that connect the headers to the y pipe and there were none (atleast at idle i didn't have anyone around to rev the motor while i was under the car)

i'm still looking for a place to to bring my car to get codes checked autozone only had a setup for obdII and mine is obdI with a obdII connector.

i checked the fuel pressure at it was at 39. i read on a post that it should be at 41-44 at idle. So i raised it to 41.5. could this have been the problem?

just tring to rule things out before i buy a new cat

 

are the plugs set to proper gap? maybe opening them up to get a hotter spark would help burn the fuel better.

 

got a bottle of sure pass and a high thermostat, i get my buddies to pass with this alll the time.

 

Its most likely none of the above except the CAT.

Here is why, your CO levels indicate how much fuel is going in/how well the engine burns it off, your CO is pretty low which indicated that your o2's/wires etc.. are most likely good.

HC is high while CO is low means the enigne is managing ok but the CAT doesn't burn anything off, no cat = never pass.

NOX is relatively on the high side too, although your EGR does a great job in keeping that down, all new 3 way catalyst lower your NOX as well.

My opinion? Get a new cat.

 

at this point i guess it alot has to be the cat i've checked almost everything else. i'm gonna go check my car for a trouble code and if nothing turns up i'm gonna get a new cat.

i'll prolly go with carsound cat and slp shorties w/ y-pipe. its alof of money but my headers r really rusted and so is my y-pipe and i know they muffler place won't weld on it. will i see any added proformance from slp 1 3/4 and the carsound highflow cat over my stock y pipe and cat and edelbrock headers?

 

Have you considered taking to a shop for diagnosis instead of throwing parts at it?

 

i beleive not 2 posts up he said he is going to get it scanned

 

what kind of a shop would do this kinda stuff. the shops listed on the 2nd page of the emissions report are shop that some of my friend work and and i know the guys who work on the cars. all they know is what their autotap type device tells them. if i don't throw a code they don't know whats the matter. both of the shops that i failed the emissions test at couldn't tell me whats the matter. all they said they could tell me is that i failed the hc portion of the test. And if i spend $300 and make some type of improvement i get a waiver from the state.

If u read the post u would have noticed that i have been narrowing down what the problem could be. I haven't totally narrowed it down so i haven't baught anything yet so i hardly think i'm just "throwing parts at it".
I do all the work on my car unless it requires some type of expensive tool or some type of special skill i don't have. part of doing all the work on ur own car is doing things that u might not know exactly how to do. this is how u learn about ur car and get better at working on cars.if people never did ur own work this site wouldn't exist and neither would hot rodding cars. working on ur own car can be expensive and require a little more money in some cases to get the job done. I personally would rather do something twice and know what the problem was than go give it to someone else and pay them to do it and not know anything about whats going on with ur car.

 

cats are good only for nox...what a load of crap!! if that were true the factory would never have spent the time or money to install them on your car...they would just program the ecm to run rich ..that would prevent any and all nox..

according to the Corvette and Camaro fuel injection guide...the #1 reason for failed emissions is for (HC) AND IS CAT FAILURE......just clean your maf sensor anyways (with rubbing alcohol and cotton swab) it may not look dirty but just in case...otherwise change the cats...

 

I second that!! replace the cat. Also, lower your fuel pressure, it is too high. engine runningm vucuum line removed, it should read between 41 to 47. Then, with the line on the pressure should drop 3 to 10 psi with engine running. Remember, you must remove the vucuum line to set the fuel pressure.

 

So i start the car and hook up my fuel presser tester guage and pull one of the vacume lines off the intake and it should read 41 to 47. then what do i do ?
" with the line on the pressure should drop 3 to 10 psi with engine running"
so with my engine running and no vacume lines taken off it should read 3 to 10 psi? mine read 39 when i tested it at idle.

thanks everyone for the help

 

I was failing AZ emissions last year for high HC at idle. AZ checks HC and CO at speed and Idle. Levels were well within at speed and only HC failed at idle. My problem was a small leak in my EGR Tube. Exhaust leaks cause the O2 sensor to sense a lean condition will increase fuel to that side.

I see in your signature that you're runing headers. You might want to do a very careful inspection of the header flangers and EGR Pipe and look for any soot or carbon spots that might indicate an exhaust leak.

I would make absolutely sure that you don't have an exhaust leak forward of your O2 sensors before buying a Cat.

 

Take the vacuum line off of the AFPR. With engine running and vac line removed, you should see 41 to 47 psi. With the line back on, you should a 3 to 10 psi drop. So, if your fuel pressure is set to 45 with the line off. Then you should see it drop at least 3 psi when you reconnect the vac line, 42 psi.
that is it, as long as the reading is between 41 and 47 psi and when you you reconnect the vac line the fuel pressure drops at least 3 psi.