Failed emissions

[gen2rt]

94 zr1 with haibeck top end work. Headers, no cats.

Passed everything except the hc at idle. Allowable limit is 220. Tested 3 times, read 561, 260, and 461.

Car sat for two years, I think I've run most of the bad gas through it, currently on second tank of fresh gas, added fuel system cleaner to both fill ups. Only issue with the way it runs is an off-idle stumble.

Ideas?

Thanks,
Jack

[LGAFF]

move to another state

[LGAFF]

probably a tune someone could do for the test

[Kevin]

Injectors going bad?

[gbrtng]

put cats on it

[gen2rt]

Well, yeah, putting the cats back on is the obvious solution, but I've seen posts where they've passed without them. And it's fine at higher rpms. I'm thinking its related to letting the car sit. The way it acts from zero throttle to a little bit open, if it was carburator, I'd look at the accelerator pump. I don't know what the equivalent to that is with fuel injection. Was hoping to hear from someone very familiar with the fueling systems and what might be causing it to run rich just at idle. The car has only 19,000 miles, new plugs were put in about 2,000 miles ago. I hate to go the effort and expense replacing the injectors and then discover it doesn't run any differently. The secondaries are wired open, if that makes any difference.

[mike100]

The tune is adding fuel and timing which will raise emissions, but you could still pass if you had the oem cats. Not having cats with a chip...you don't have a prayer. At least put a stock chip in it.

[mike100]

probably a tune someone could do for the test

I'm expecting my registration renewal in the mailbox any week now. My car passes normally, but I'm curious to see if I cheat like VW to lower the NOx, how much it will help.

[BigJohn]

Replace cats

[GOLDCYLON]

94 zr1 with haibeck top end work. Headers, no cats.

Passed everything except the hc at idle. Allowable limit is 220. Tested 3 times, read 561, 260, and 461.

Car sat for two years, I think I've run most of the bad gas through it, currently on second tank of fresh gas, added fuel system cleaner to both fill ups. Only issue with the way it runs is an off-idle stumble.

Ideas?

Thanks,
Jack

No CATS = no PASS

[GOLDCYLON]

Well, yeah, putting the cats back on is the obvious solution, but I've seen posts where they've passed without them. And it's fine at higher rpms. I'm thinking its related to letting the car sit. The way it acts from zero throttle to a little bit open, if it was carburator, I'd look at the accelerator pump. I don't know what the equivalent to that is with fuel injection. Was hoping to hear from someone very familiar with the fueling systems and what might be causing it to run rich just at idle. The car has only 19,000 miles, new plugs were put in about 2,000 miles ago. I hate to go the effort and expense replacing the injectors and then discover it doesn't run any differently. The secondaries are wired open, if that makes any difference.

Some states use the treadmill and other use just a sniffer with no treadmill. That is why SOME folks pass. Put on a set of random tech or flowmaster hi flow cats