Finally passed emissions!!!!

[glkuntz]

ZR1 Don
I'm curious, where did you find Ca approved Cats for your 1990. The cats in a 1990 are part of the exhaust header and as far as I know they are not available from anyone. There is a Chey service bulletin which states that 1990 and 1991 ZR1's which need cat service should be updated to the 1993 and up total exhaust system.

If you added cats to the existing 1990 system they probably won't work as they will not get hot enough as they will be too far away from the engine.

Unfortunately many automotive supply houses list the standard 1990 ZR1 and the 1990 L98 as having the same exhaust system and if you believe them you could buy cats and install them and they wouldn't work.

If the car is in good tune and does not have blowby or other issues it should pass with good cats, but these are not available. There is a workaround to this problem. If you have a certified smog repair station certify that the car is working properly in every way but the problem is limited to the poor performance of the cats you can apply to a program called the BAR Parts Exemption Contractor, and they will give you a list of suppliers to contact to verify that the 1990 headers/cats are no longer available and when you have done that and provide them with the certification of cat problem from the smog station they will issue you a limited exemption for the cats.

With that in hand you take the car to a BAR Referee and they will inspect the car to verify that it has not been modified in any way and that all the factory equipment is in place and then they will run a standard smog test. If it fails that, as it no doubt will, they will give you certification based on the parts exemption that will allow you to register the vehicle.

This will allow you to get the car back on the road legally. The bad part is that you will have to go through this same process the next time you need to register the car.

I know the above works as I have just completed the process on my car and I am going back to the referee next week for the final time. I did not get the certification from the referee the first time as I did not have a receipt from a certified smog station indicating the cats were bad. I now have the limited exemption and the referee indicated that he will give me the certification once I give him the exemption and the receipt.

I wold recommend that You can go online and get a list of BAR approved Gold Seal smog stations and take your car there to have them very what the exact cause of the failure is. They can do two different tests to verify the cats are weak or bad.

I realize most of these problems have been caused by the more restrictive standards that are now being imposed as I stated in an earlier post. The excuse of going back to the original standards does not apply, in my opinion, as the original standards the cars had to meet did not include tests at speed only a part per mile spec. See:http://www.arb.ca.gov/msprog/onroad/...31_5d7_ta0.pdf

There is an ombudsman program with the BAR where complaints can be taken and I feel that if a data base of owners with cars that would have passed with the standards in place from last year were presented to the ombudsman we might have a case. Realize this would only bring the standards back to last year so the car still has to be in good shape. The case needs to be presented in a factual non threating or emotional manner.

I have all the documents from the BAR to backup everything I have stated in this post.

Sorry for the long message, but I have about 100 hours in dealing with this problem and I would like to prevent others from having to repeat my efforts.

Gary, 1990 ZR1 #556

[glkuntz]

SoCal ZR1

Congratulations on passing. You were very lucky. My car will also pass, after about $800 worth of fiddling around, but only when doing the 15MPH test in low gear. Unlike your test guy the state requires the test be done in 2cd gear and every station I have taken it to will only test it this way.

I would prefer to pass this way as opposed to using the Parts Exemption method that I have describe in a previous post. Anyone know of a Test Only station in Norther Calif that would test it in low gear. You may want to PM me with an answer to no get anyone in hot water.

Gary, ZR1 #556 glkuntz@aol.com

[zr1don]

Gary,

Thanks for all the info, the cats I purchased were magnaflow from a local muffler shop. They had a book with approved cats for each model engine and year. They could not be used w/stock 90 manifolds w/o serious mods to the manifold. I have SSW headers w/stock air injection tubes installed (all operational} and the test station I use did not question them on the visual. He did check the numbers on the cats. I agree, I do not think the cats located downstream from the headers work as well as the stock cats attached directly to the exhaust manifold. I would prefer not to go through all the referee procedure every two years, except as a last resort. I have found a couple of minor possible contributing factors that I have corrected and will be testing again to see if I can pass. I wouild like to join/support you with any action taken to get these standards changed.

[RedRiderZR1]

Its time for me to go through this again as well. Will be taking my 90 in soon to see how it does. Last time I took it in for a smog check it was way below average on everything. Smog guy was amazed. Will see how it goes this time. Car is stock except for Catback, X-pipe and DRM chip.

Will report back here how it does on the test.