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Can't pass emissions

601 Views 5 Replies 5 Participants Last post by  Supersix
I am having a HELL of a time passing my car here...I keep failing hydrocarbons by like .2 and .3 tenths of a point...it's very close...i was actually closer to passing with the extender chip (which doesn't even use EGR) than i did with my jim testa 93 street chip (which does use EGR)

i have a hi-flow cat on right now...i am passing carbon monoxide with flying colors...i put my fuel pressure REALLy low to like 30 psi line on...is that too low of a pressure for 50's? what kind of gas should i run? should i put in 100 unleaded instead of 93? i also ran the car at 200 degrees...any tips would be greatly appreciated...
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I don't think you are supposed to change your FP. Leave it around 38-42, vacuum off. I believe someone posted that with too low FP, emissions can go up. Make sure you have changed your oil recently as well. I would run just pump 93. Mine passed with flying colors on 50's with a Casper street chip and 38# FP on an IM240 dyno with a 3" cat (new and only used for emissions every other year).
i forgot to mention that they run just the dyno test...no idle test...and yes my egr is fully functional...i have the hole drilled out for the power plate...they run the car up to 30 mph and test both exhaust pipes...the standard for carbon monoxide is 20.0 and i registered 2.30 which is a major pass...

the only other thing they test is hydro carbons and the standard here is 1.40! i am registering 1.62 and 1.70...i am so close...should i throw some kind of fuel additive in there or something??? was my fuel pressure too low? when i registered 1.62 my fuel pressure was 45 line off with the extender chip
Your car needs to be in a good state of tune to get by the HC tests. And lowering FP that low just took you completely out of that arena.
Let the computer do it's job, that's what it's designed to do.
It's very easilly forgotten that any changes in fuel pressure are going to be pretty much ignored because the ECM is going to change the BLM's to compensate for fuel pressure changes. That is to a point. IF you adjust FP too far in either direction the BLM's cant compensate, and the the car will either go too lean or too rich. In either case HC's are going sky high because of that.
If your cat is good you should be able to blow the HC test away!!

Get a good smog chip. What that amounts to is a stock chip that has been cut for the injectors you have. Proper engine temperature,and other variables will then be at stock levels and you should have no problem with any smog chip.

It's really quite easy to pass, but you gotta not try tricking the system with troublesome fuel pressure adjustments. The perfect fuel pressure to have is that which yields idle BLM's anywhere from 120-135 or so.
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HC is unburned fuel.

If you were closer to passing with an extender, then I wonder was it running open loop? I ask because, sometimes a car will like a little more fuel. This can lower HC (depending how much fuel).

What plugs are you running and what is their gap? If like R42's at .030, try 43's at .035

Since my chip is based on the 87 recall, with some driveability stuff played with, I must suggest theres something with the car, and not the chips. Especially since both chips netted 1.6gpm+ values.

Since CO passed, I'd be looking for the source of a random misfire. What size cam are you running? One with much more overlap than stock WILL cause a HC failure as overlap is used to have exhaust gas draw in intake charge. While this is happening, some of the intake charge is sucked out the exhaust unburned. The result is HC out the tailpipe.


<small>[ August 09, 2003, 06:34 AM: Message edited by: TurboJim ]</small>
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I always used RXP, an emissions reducing fuel additive, changed the oil, used a fresh CV893 PCV valve, and made sure the car wah hot when I get there. I used to pass with flying colors w/a hollowed cat/blue tops/standard mods..

But they did away w/emissions here :D
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