Passing CA Smog help - High HCs

[Frankenchevy]

Is the truck a heavy half? If no factory cat, I’m not sure the cat would need to be CARB certified or not.

 

[CalSgt]

Is the truck a heavy half? If no factory cat, I’m not sure the cat would need to be CARB certified or not.

C10's with either Big 10, heavy half, (F44) didn't have cats in 75-77. If it's not required to have a cat at all I don't see how a smog tech could ding you for using a federal standard type cat instead of one with a CARB EO.

I think federal standard type cats can be had for $130-200 for quality branded stuff. Not a bad investment to get the HC's in check and would clean up the exhaust smell a bit too.

 

[DoubleDingo]

Definitely take it in hot by driving around for 40 minutes to an hour, and do everything that everyone has said to, and it should pass no problem.

I'll be going through all of this soon. For some reason I have to test again this year, maybe because it had issues passing last year, I don't know. Either way, I'll be doing an oil change, a tune-up, retarding the timing to what it says on the sticker, also making sure the carb is adjusted properly, and getting it good and hot before taking it in.

 

[77Matt]

Is the truck a heavy half? If no factory cat, I’m not sure the cat would need to be CARB certified or not.

Oh interesting - Ill ask the SMOG guy when I take it in with the new carb. The GVWR is 6050 - I read that >6000 for that year did not have a cat. Its dual exhaust but I dont think that is indicative of Heavy Half's. I wouldn't know by looking at the suspension. I am new to this game.

 

[77Matt]

C10's with either Big 10, heavy half, (F44) didn't have cats in 75-77. If it's not required to have a cat at all I don't see how a smog tech could ding you for using a federal standard type cat instead of one with a CARB EO.

I think federal standard type cats can be had for $130-200 for quality branded stuff. Not a bad investment to get the HC's in check and would clean up the exhaust smell a bit too.

The failed smog report just stated "not applicable" in the catalytic converter visual inspection

 

[Frankenchevy]

Oh interesting - Ill ask the SMOG guy when I take it in with the new carb. The GVWR is 6050 - I read that >6000 for that year did not have a cat. Its dual exhaust but I dont think that is indicative of Heavy Half's. I wouldn't know by looking at the suspension. I am new to this game.

Do you still have the build sheet with RPO codes in the glovebox?

 

[fast 99]

Oh interesting - Ill ask the SMOG guy when I take it in with the new carb. The GVWR is 6050 - I read that >6000 for that year did not have a cat. Its dual exhaust but I dont think that is indicative of Heavy Half's. I wouldn't know by looking at the suspension. I am new to this game.

Back when we checked emissions this state published a little pocket book with all the OEM required devices by brand, model, year, engine and GVW. California should have something similar available.

Wish I would have saved it.

 

[77Matt]

Do you still have the build sheet with RPO codes in the glovebox?

Quite possibly, Ill check it out when I get home tonight. My dad picked it up about 10 years ago from the original owner.

 

[fast 99]

Did it fail for high HCs or NO with the clogged EGR?

A non-functional EGR would likely fail on NOx. Stuck open [even slightly] would increase HC substantially. EGR provides inert gas to intake charge to cool the combustion process.

The way to look at emissions is this, CO is unburned fuel, HC is partially burnt fuel, NOx is produced by excessive heat.

 

[77Matt]

A non-functional EGR would likely fail on NOx. Stuck open [even slightly] would increase HC substantially. EGR provides inert gas to intake charge to cool the combustion process.

The way to look at emissions is this, CO is unburned fuel, HC is partially burnt fuel, NOx is produced by excessive heat.

Interesting. Looks like Ill check the EGR valve as well. Hopefully I can get it back in to Smog within a week. Thanks

 

[dd1990]

Clean or replace your EGR...also check your vacuum lines and replace if needed.

 

[77Matt]

Do you still have the build sheet with RPO codes in the glovebox?

Using the VIN, it has the RPO code F44. According to the code sheet I see, it means:CHASSIS EQUIPMENT,HEAVY DUTY. Does this mean it would be 'Heavy Half'? Sorry, as I mentioned I am pretty new to this game.

 

[SquareRoot]

How does driving around for an hour get it any hotter than driving it to the testing facility? How about power braking it just shy of a burnout before pulling into the machine? I know the price of gas in CA is probably $5/gallon? At the typical 10 mpg, I think it's flawed logic. What say RP?

 

[Frankenchevy]

How does driving around for an hour get it any hotter than driving it to the testing facility? How about power braking it just shy of a burnout before pulling into the machine? I know the price of gas in CA is probably $5/gallon? At the typical 10 mpg, I think it's flawed logic. What say RP?

No way! Costco is down to a palatable $4.459/gallon for 87. Not going to lie, I had to look that up. It’s been a while since I’ve been to a gas station.

 

[77Matt]

No way! Costco is down to a palatable $4.459/gallon for 87. Not going to lie, I had to look that up. It’s been a while since I’ve been to a gas station.

I'm not worried about gas prices. It's for in town fun runs and little league games - with the occasional dump run.