Hello, firends.

my 1994 Del Sol is not passing the emissions test. If I may advance a theory, the culprit is an e-bay $50 "Header" I installed about 3 months ago to replace a severely-cracked OEM exhaust manifold (I could not find a used OEM on craigslist at the time, and they were ridiculously-priced on ebay). I would like to hear your opinions, however. Besides the header, the D16Z6 and ECU are completely stock.
So here is some background information: When I installed the header, I also installed a new Denso Oxygen sensor. About the same time, I changed the spark plugs with some Autolite Iridiums, and installed new Accel wires, and distributor cap and rotor. Shortly after, the CEL came on, so after reading up on these forums, I replaced the distributor (with a used unit) due to a bad TDC sensor, which remedied the problem. Unfortunately, I did not have a timing light at the time, and I needed to drive the vehicle (my DD), so I simply "eyeballed" the ignition timing and zipped everything up. Last month, I had the car smogged, and passed everything except for Hydrocarbons at idle. Reading up on this forums, I found a post that said the problem was most likely the ignition timing. Remembering that I hadn't properly set it, I purchased a timing light and set everything right. I then had the car tested, but failed the same test. The catalytic converter was changed over 2 years ago, and the air filter is about 6 months old. Currently, CEL is off.
Here is the info:

High Speed (2553 RPM's):-----Low Speed (730 RPM's):-----Limit:
HC---------------70 ----------------------317-----------------------180
CO---------------0.48---------------------0.47----------------------1.20
CO2-------------13.2---------------------11.7----------------------XXX
O2--------------2.54----------------------4.55---------------------XXX


Any suggestion welcome, or if I forgot any relevant info, let me know. Thank you, guys.

 

I'm not sure, but didn't that motor come with a header with a Warm up cat on it?

 

My sister drives an '01 Civic with the 1.7L and the exhaust manifold has what appears to be a cat on it. Is that what you are referring to? My car did not have that.

 

ummm... anyone?