Can you guys help me figure out what I need to do to fix this problem?

1990 Camaro RS
305 TBI

Let me know what other info could help.

 

is your car stock?

 

All stock except 3" pipes from the cat back... so yes.

 

Be glad you didnt get these numbers

 

harley, check the egr system. your car looks like it runs ok, minus the ridiculous NOx. thats were i would start

 

Cant help much on this sorry....

Because we are talking smog, I do have a question:

If the motor is running lean, will it make the emission numbers lower?? in other words will it be easeir to pass??

Any information will be greatly appreciated.

Brad

 

I'll start there. How do I check that?

 

first thing is check for codes.
http://www.sethirdgen.org/dtc.htm

i would like to see your CO2 higher, it shows something isn't quite right.

on the HC problem, it looks like you may be a little on the rich side.
you need to check the data stream & see what your INT & BLM are running at.
also, make sure the motor is getting up to operating temp, what temp T-stat do you have in it?
is your O2 sensor old? if its pretty new, is it a A/C delco?
it doesn't look like you have any misfire problems, but are the spark plugs, wires, cap, rotor & ignition coil in good condition?
do you still have the original cat on it?

on the NOx problem, you almost certainly have problems with your EGR valve.
i think you may find a code 32 when you check.
test the EGR system.
https://www.thirdgen.org/egrdiagnose


TraviZ, did you ever get your car right?

bluegoose, leaning the mixture out can help, but if you go too lean the HC will shoot up & NOx will more than likely go up.

 

to a point, yes. lean mixtures make lots of heat, so NOx will go up. HC's will drop as will CO. a stockish car running properly shouldnt make too much emmisions, so if you're trying to "pass", try and find the problem and fix it.

 

Most of what your saying is going over my head... HC, INT, BLM

BUT... I did check for codes... I'm not totally useless... And I got a code 42 (Electronic Spark Timing or Bypass fault) which puts me back at

I think the tstat was a 170 with a hole in it... it gets VERY hot in the summer and sometimes on the fwy.

I'm not sure how old the o2 sensor is, but I'm sure it would have been ac delco.

"But are the spark plugs, wires, cap, rotor & ignition coil in good condition?" Yes.

Do you still have the original cat on it? No.

I'm going to look at the egr link...

 

Frank:
You need to change the cat to get the Co% down under .2
You need to redo the EGR to get the NOX down. It will always cause the high NOX with a free flowing exhaust. The backpressure is too low so the valve needs more vacuum assist. I usually drill the vacuum hole to about .020.

 

Hi Don!

I am going to change out the cat asap.
I would like to do the egr thing, but can you give me more info on it? Or point me to the dummy pages for egr? Drill a hole where??

Thanks!

 

On the EGR valve there is a port the hose goes on, it has a very small hole in it, it needs to be drilled to .020.