Failed CA Smog. Looking for some direction

[KelSMJ18]

Hello all,

Took my 1989 GMC Suburban 5.7L 350 in today for its first smog. Did some tuning up on the burb and I've got it running well so decided to give the CA smog a try. Everything passed except a couple things:

1) Fuel Cap Functional: Fail (ok get a new fuel cap, easy)
2) Catalytic Converter: Modified (the cat on the vehicle is not California compliant so I have to buy and install a new cat)

and this is the one I need help with

3) Idle Emission Test Results: Gross Polluter

They ran a emission test on idle and the HC (PPM) that was measured reached 1008. The max allowable is 220. So I assume the vehicle is running very rich. My question is where do I begin to bring this HC (PPM) down. Attached is the Smog result. Thanks for the help!

Kelley

 

[dd1990]

Could be alot of things,

I would check all wiring to sensors: 02, throttle, IAC, ignition and check injector spray.

Ive had rich idle turned out to be 02 sensor.

The cat you have now is it a high flow cat?

 

[Sad Sack]

Move.

 

[Lorenblazerk5]

Great suggestion from Sad Sack.
California is super frustrating with regards to smog. That why I'm leaning toward 1975 and older to avoid the money grab.
I would work with a smog shop that can tune it so you will pass, normally a pass will be the worst set up for a smooth running engine.

 

[Ricko1966]

Start with a good tune up, plugs, wires, cap rotor. Set the timing but retard the timing a few degrees. Retard timing will help clean up CO. That's one of the reasons the factory went to ported vacuum in later years and even timing specs that were after TDC. Not the best for performance and it makes the engine andvexhaust hotter. But you can re time it later.

 

[Radiohead]

High hydrocarbons can be piss poor ignition or too lean a mix. Things to rule out, ya know. What were the CO, CO2 and NOx numbers? It all plays together.

Ain't that right @Ricko1966 ?

 

[NLD79K10]

As @Ricko1966 already said, start with a good tune-up as high HC with no high CO is most often indicative of an ignition issue.
Also check for any vacuum leaks and leaking injectors as that can cause the same issues, especially at idle.

 

[goldpack]

@bucket
would you want to merge these two threads started by this new member.
going to generate same responses,...so merging them would let those responding see what was said earlier in the timeline easier.

https://www.gmsquarebody.com/threads/hello-from-a-89-gmc-suburban-from-northern-ca.49974/

edit: and @Frankenchevy here is a report attached from the smog police.

 

[bucket]

@bucket
would you want to merge these two threads started by this new member.
going to generate same responses,...so merging them would let those responding see what was said earlier in the timeline easier.

https://www.gmsquarebody.com/threads/hello-from-a-89-gmc-suburban-from-northern-ca.49974/

edit: and @Frankenchevy here is a report attached from the smog police.

Nah, they are good. One is just an introduction thread, the other is a tech thread.

 

[Finkaire]

Full tune up, plugs, wires, cap and rotor and then find a good tuner in your area

 

[chris3353]

Hello all,

Took my 1989 GMC Suburban 5.7L 350 in today for its first smog. Did some tuning up on the burb and I've got it running well so decided to give the CA smog a try. Everything passed except a couple things:

1) Fuel Cap Functional: Fail (ok get a new fuel cap, easy)
2) Catalytic Converter: Modified (the cat on the vehicle is not California compliant so I have to buy and install a new cat)

and this is the one I need help with

3) Idle Emission Test Results: Gross Polluter

They ran a emission test on idle and the HC (PPM) that was measured reached 1008. The max allowable is 220. So I assume the vehicle is running very rich. My question is where do I begin to bring this HC (PPM) down. Attached is the Smog result. Thanks for the help!

Kelley

Get Winaldl and the cable. Data log and check for errors in real time.

maybe timing, maybe a dripping injector?

 

[Oldsnut]

Also check you temp sensor for computer. If it has failed it could be telling computer it is cold and forcing a very rich condition no matter what the O2 sensor is saying.

 

[82SquareBurb]

Move.

Best advice ever! I remember the catalytic converter cartel in CA, same exact cats but with a carb number stamped into the side, with big $$ tacked on the price. Feel for those that get sucked into that con.

 

[Frankenchevy]

I bought this cat for $150 and it has a CARB EO number on it. Looks like it’s about $185 now:

You must be registered for see images attach

Pardon Our Interruption

You can ohm out your spark plug wires. Should be able to find how many ohms per foot they should be online. You can also test your coil. Visual on the plugs, though if you’ve gone through the trouble pulling them, I’d put a set of properly gapped new ones back in. The correct ACD plugs are still relatively cheap. The cap and rotor are similarly cheap, but again, I’d probably get the ACD ones.

All the ignition stuff should be $100 or so if you elect to fire the parts cannon at it.

Do you have a timing light? Find and highlight the marks on your balancer and tab. Disconnect the (brown iirc) wire near the steering and brake booster on the firewall and verify timing. The instructions are on the sticker on your core support.

Does being labeled as a gross polluter mean you can only go to a STAR smog check station now?

 

[chris3353]

Forgot to say,, If you are failing at idle, Run the RPM to the exact maximum (~1400???)

I used to pass idaho, Cam, headers, hollowed out cat. If i let it idle at 600 it would fail