1989 350 Failed California smog :-(

[MrTruck805]

Hi All,

My 1989 Fullsize Jimmy with the 5.7 350 failed California smog the other day for too many hydrocarbons at idle. I believe hydrocarbons were ok at the higher speeds, and all the other numbers were ok as well. I believe it has to be under 120, and I was fluctuating around 180-400. So basically a little too much unburned gas was going through the exhaust. They measured the temperature of the exhaust before and after the Cat, and the temperature increased so they told me they thought my Cat was Ok. Is this the standard test for a Cat? I drove around quite a bit beforehand too to make sure it was hot.

The engine as 200k+ miles on it, but runs strong. The TBI has a few mods including the Spacer, Pod Spacer, and Salad Bowl.

My plugs and wires are brand new. I can do an oil change, run a bottle of the fuel injector cleaner through the gas tank, and fill up with premium before my next try at passing. Any other tips on lowering the HCs?

Thanks!

 

[snowdriver]

Retard the timing about 10 degrees,will run weak,but it should clean up the hydrocarbons,then put the timing back when you get the certificate

 

[rampage]

A temp difference between inlet and outlet of the cat is one way of determining if it's functional. It sounds like yours is fine.
I'd start by going over this checklist:
http://www.smogtips.com/failed-high-hydrocarbons-HC.cfm

How is your cap/rotor? If there's carbon buildup inside then it'd cause a dead cylinder. I'm guessing there's no codes/CEL since that's an automatic fail.
On my 2000 F150 with 300k miles I use Bluesky (available at Napa) and it passes with almost unmeasurable readings which surprises the technician (and me). Don't know if that's what gives it such low readings or if it helps but I'm not going to switch up and find out.
http://www.blueskycleanair.com/

 

[MrTruck805]

Thanks for the replies.

Cap and rotor are good. I forgot to mention no codes. It hasn't thrown a code in years.

I did have to get a new battery recently, and it was in the middle of nowhere so there wasn't much to choose from. My cranking Amps are 875, and CCAs are 650, which I believe is slightly underpowered for the vehicle. I wonder if a smaller than desirable battery could be giving me not enough spark.

We don't have a napa here, but I assume I can get something similar to blue sky at o'Reilly's or autozone (local equivalents).

 

[scottsdale86]

Retard the timing about 10 degrees,will run weak,but it should clean up the hydrocarbons,then put the timing back when you get the certificate

It won't pass the visual if the timing is off from the underhood decal. Assuming they check it like they are supposed to.

 

[snowdriver]

It won't pass the visual if the timing is off from the underhood decal. Assuming they check it like they are supposed to.

They don't look under the hood here in oregon

 

[scottsdale86]

In CA you have to pass an underhood visual test then the actual roller/tailpipe test. All the emissions equipment must be as it left the factory and be at base setting as per the underhood decal.

 

[4X4HIGH]

In CA you have to pass an underhood visual test then the actual roller/tailpipe test. All the emissions equipment must be as it left the factory and be at base setting as per the underhood decal.

Actually in Ca. The timing cannot be off more than 4 degrees otherwise it's an instant fail.

 

[scottsdale86]

I was instructed by the smog ref at the local college that if I was off by any then the vehicle couldn't proceed with testing thus failing the test. He had lots of good tips on LS swaps too.

 

[rampage]

According to the link I posted earlier:
"California allows 3 degrees +/- off of the manufacturer's required setting."
I looked for the actual law at the CA bar site but navigating that and finding anything is like hunting for a needle in a haystack.

 

[lizard49]

I'm in the same boat, failed as gross polluter because running rich at idle.

What was the fix?