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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: 86square on December 26, 2021, 09:47:34 PM

Title: Emissions
Post by: 86square on December 26, 2021, 09:47:34 PM

California smog failed any help
(https://uploads.tapatalk-cdn.com/20211227/a7fefdbb5ce61c646303fa1b4b7af541.jpg)
Do y’all think it’s my carb?


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Title: Re: Emissions
Post by: JohnnyPopper on December 27, 2021, 05:31:29 PM

Looks like it was at idle and 1314 RPM?

Did he do a high speed test at 2500?

Title: Re: Emissions
Post by: MIKE S on December 27, 2021, 09:20:19 PM

Basically high Nox is to much heat in the cylinders. Egr system introduces exhaust back into the intake to “cool” the cylinder temperature. Carbon deposits are another factor that can glow in the cylinder and cause problems. To much timing is another factor. Make sure the egr diaphragm is actually moving and that the passages are not restricted. Keep timing as close to 0 as possible for testing. Try to de carbonize the cylinders.

Title: Re: Emissions
Post by: VileZambonie on December 28, 2021, 07:22:08 AM

I agree with Mike S, check that EGR first.

Title: Re: Emissions
Post by: MIKE S on December 28, 2021, 01:30:23 PM

I see in the report that they did a functional test of the EGR. Don't count on it. I used to have a Calif smog inspectors license. I would check them. Most would not.