1990 gat 5.0 five speed. It passed but I would like to see better results on the HC results. I've got two ears to figure it out. Any ideas would be great.

Here are a couple of photos. 2015 results and then this years.
Thanks for taking a look.

Bob

 

Need more info. When was the last time you changed cap, rotor, plugs, and wires? Oil changes regular? Have you cleaned the fuel injectors? When was the last time you changed your fuel filter?

 

Sorry Oil change just before this smog, everything else except injectors was done last time.

I use a fuel injector( Techron) on a regular basis. For this smog I ran a tank of fuel thru using Seafoam.

Bob

 

HC shows no change, but your NOx is slightly better. It passed so no worries until 2019.

That print out looks like a CA test. If you don't mind me asking, what CA county are you in?

Any engine mods?

 

Yes it is a California test. Live in Riverside county and in riverside city do we have to do the inhanced test.
The car is stock completely with no mods.
Im not sure how old the cats are or if they are original. I'm the fourth owner and bought it ten years ago in the Seattle Washington area. They do not test cars over 25 years old.
Bob

 

We dont test cars ever in Alberta, but im sure it is coming.

 

Next time use about a gallon of denatured alcohol to a 1/4 tank of gas. Retard the timing to 0. They will have trouble measuring it. LOL. I've got some pretty ugly things to pass smog this way. After the test promptly fill it with premium and reset the timing.

GD

 

When my brother took his 92rs camaro to emissions for its final year of inspections there was this grumpy old-timer there who was doing the test. If I remember correctly the car at the time would occasionally stall out which it did during the test. the guy started freaking out saying, "it smells like raw gas!" or something along the lines of that because he thought my brother was trying cheat the test and that was why it stalled lol.

 

WHOA. I've used a quart to a half tank. CO goes to zero.

 

Unfortunately, can't do this in CA. It won't pass visual.

It can be done, but it needs to be undetectable.

 

I wish you were correct. cali did away w/ the rolling 25 year exemption. It is fixed at 1975 and older, no smog test.

In fact, a few years back, cali LOWERED the max allowable to BELOW the ca. max allowable, when the cars were almost new. cali's war on older cars.

 

Happened to me back in 2011 with my '92 Lumina. The state sometime between 2009 and 2011 lowered the maximum allowable limits for HC, CO and NOx by 30% across the board.

I had passing measurements in 2009 which now failed in 2011. Yes, the car is currently registered.