Need to pass emissions one last time.

[Buxom]

Well, I'm looking to pass emissions one more time, my truck is 24 years old and I need to get from 2771 NoPPM to 822. No more emissions in Virginia for a 25 year old vehicle. It's a 1993 SR5 V6 auto.

I'm not sure where to begin, but I'm guessing I should at the very least do a CA legal catalytic converter and the oxygen sensors. Full tuneup was last year, all vacuum lines redone, EGR system passed, though I've got an error code 71, which means EGR. Idle is a smooth 800 at operating temp. Any ideas, any tricks that'll make it pass for just like 20 minutes for the test? I'm not looking for a big bill, I've got a corolla to restore this month as well. I've got about $1500 disposable after bills because I get paid 3 times this month.

Thanks in advance.

 

[4loco]

Not sure if it actually did anything but we put 20-50w oil in a 1983 corolla and it passed with flying colors. My dad literally tried to get it to fail smog by plugging vacuum lines etc to get the $1000 Obama rebate, but it still passed with flying colors. Was it the fresh thick oil? Idk, could have been a fluke. He ended up selling it for $950 a day later, lol.

 

[Buxom]

Ouch.

How bad did it run with 20/50?

 

[WRM1]

Here's a couple of items that might help

What Causes High NO - Nitrogen Oxide - SmogTips.com. Why did my car fail emission test high NO emissions. What is NO. My vehicle failed high nitric oxide emissions test. Produced high NO. Common high NO failures. NO emissions. How can I lower NOx. Co

NOX failures (all vehicles)

1. Improper operation of the EGR valve. Stuck open, obstructed, leaking, or misrouted EGR vacuum lines.

2. Plugged EGR passages. Carbon build up in passages.

3. Over advanced timing.

4. Too lean of fuel mixture.

5. Engines cooling system in poor condition, causing excessive temperature.

6. Malfunction of the electronic spark control (ESC), and knock sensor. Computer fails to retard timing.

7. Contaminated or bad catalytic converter.

Maybe starting with the EGR failure would help. The cat replacements will be the most expensive, so avoiding those is probably key to protecting your budget... I've also seen engines that had some carbon buildup that increased effective compression ratios, so maybe a decarbonizer would help.

I've seen some articles that say that ethanol makes NOx worse, so if you can get some non-ethanol gasoline, there's a chance that will reduce the numbers.