Failed emisssions-need help

[Sgreg]

Just put on new headers, RT cats, new O2 sensors and PCV valves and proceeded to fail the emissions test. No other mods to car. NOX was on the high side particularly at low speed. Car runs great. No codes. I drove the s--- out of it before taking it in to be tested. Is is time to get out the alcohol or what ? Any suggestions would be appreciated.

[rkreigh]

what state and what were the readings??? a couple of things to try. the lt5 is a carbon machine, and it can sometimes take a bit to clean out the pipes. the low restriction cats aren't as efficient in cleaning up the emissions so the testing can be dicey. if the car is running rich you can try a bit of alchy, but be careful if it's an early z (90-92) as the alchy can hurt the windings in the coils. with the crap 10% alchy gas you're getting that anyway. some other basics, fresh oil, fresh plugs, and make sure the wires, coils ect are good to go.

haibeck can also help you out with an emissions chip if all else is up to snuff, but I like the "get her drunk" method for fast temporary relief. it leans it out, cleans up the emissions, and can help you sneak by. just drain it out and don't even think about going WOT with the martini in the tank. the percentage of alchy varies depending on how rich you are running.

another tip, go to a station that will work with you. often running the car through the test a couple of times is all it takes to blow out the crud and get it passed. with ALL the tricks my stroker just snuck by on the second go around. I think with the haibeck chip it will be much easier next go around. I was sweating it!!!:cheers:

[Sgreg]

Thanks, Ron. I am in Texas and only my 25 MPH NOX was high (1059 ppm vs 848 ppm standard) HC was good against the standard; no CO problems. I was not aware there is an emissions chip available. I have some guys who will work with me but the test computer result is totally machine produced and they have already played with it some to get me this close. Is the Haibeck emissions chip a certain cure ? If so, sounds like a good long term investment.

Greg

[ZR1 MK]

Based on your mods, your car should pass easily. It may just need a tune. I pass well within the limits with the standard test and on the rollers. The only thing I have used is RedLine fuel cleaner.
The special emissions chip is only necessary if you have a modified chip or heavy mods like large cams that prevents you from passing.
See the website below. It explains high NOX. http://www.catalyticconverter.org/nox/