In Illinois we have the IM240 test. I failed the hydrocarbon part of the test, 0.80 is the limit, I had 1.01. In 2001 it failed on HC also. I was told the catalytic converters were bad, I replaced both converters and both of the 02 sensors. It did pass the test after all that was done.
Does anybody have any ideas what the problem could be.
Thanks in advance.....

Emissions tests suck :mad :U

 

Ron,

I went through the same crap earlier this year with my 84 Xfire. Its been modded and would get excrutiatingly close to passing. In fact, it did pass. THREE TIMES. Except that these were voluntary and not considered an official pass. You can buy a voucher to see if it will pass. Basically my HC was fine during cruise. It failed because of spiking HC during decel. If that's the case with you, you may want to check the EGR valve first. I believe my problem happened when I put 1.6 ratio rockers on which effectively increased the duration and overlap of my cam. I believe what happened was that during decel and high vacuum, the longer exhaust duration may have overscavenged the chamber sucking out some of the fresh AF mixture. I finally gave up and got classic car insurance and applied for a waiver which I got. A LOT of the inability to pass is due to the people that drive the cars on the dyno too. They just do what the computer tells them to do which is to lug the motor at 1300rpm in 3rd gear, for example.
I can tell you that the tune on your car should be on the lean side. So rather than tuning for a 128 BLM, tune for 133 or a little higher. Also drop the pump shot since these jerks stab at the throttle. I can't tell you how many chips I burned to get it right and I would pass on the voucher, take the car around and it would fail. Also don't let the idiots overheat the car. The motor should be tested in its normal operating range. These clowns would run it over 230d. Lucky I didn't end up with warped heads. :banghead: :banghead: :mad :mad :rant:

 

Ron,
I am interested in answers to your post. My 85 is due for testing and since it has 142.5 K miles, and counting, I am keeping my fingers crossed.

Forum members any tips to help keep our cars' emissions clean?

Mark in Illinois.

 

Mabe this will help .
http://www.mr2.com/TEXT/SmogCheck.html

 

Thanks for the very informative article.

 

Thank guys for the reply's.
I dropped the car off at a local auto repair business that does Im240 emission repairs. I will let you all know what happens when I find out.

Mark, did you go to fun fest? :cheers:

 

Yes, I was able to go Sunday.
Here is an observation for the C4 vs. C5 wavers. I worked Saturday and all the Corvette owners waved back to me--I was driving a state truck on I-70.
On Sunday I was able to go; however the Corvette was not up to the trip as I just threw the serpentine belt. I drove a red German car a Cabriolet (it is very hard to say VW in this forum); and all of the driver's /passengers waved back.
It was great to see hundreds of Corvettes and meet their proud owners.

Got the new airpump and belt installed Monday.

Cheers.

 

Don't let them turn it off right before the test. They go ito open loop for up to
300 seconds depending on the temp. When they tested mine the guy stalled it starting out in first gear. I had him wait for 5 min. before he restarted the test.
It just passed.