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Won't pass calif. smog, too high hc, 1979 c30 pick up 454 cu…

Customer Question
Won't pass calif. smog...

Won't pass calif. smog, too high hc

Mechanic's Assistant: What is the model/year of your Chevy?

1979 c30 pick up 454 cu in v8

Mechanic's Assistant: Are you fixing your C30 yourself? What have you tried so far?

Rotor, cap, spark plugs

Mechanic's Assistant: How many miles are on the car? When was the last time the plugs were changed?

Compression check showed 150 psi all cylinders, just changedn spark plugs

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

It passed smog check great 2 years ago, it failed only on low idle, it was good on high idle( 2300 rpm)

Submitted: 11 months ago.Category: Chevy
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Answered in 3 minutes by:
9/18/2017
Chevy Mechanic: Wolfgang, Master Auto Tech replied 11 months ago
Wolfgang
Wolfgang, Master Auto Tech
Category: Chevy
Satisfied Customers: 5,249
Experience: Master, L1, L2, ASE 15yrs and running.
Verified

Thanks for choosing Just Answer . I'm Wolfgang here to help!!

I am confident we can resolve your problem together. Please
understand that I don't know your skill level. In most cases when you have a problem
with the way the vehicle performs, specialized tooling is required to acquire computer
data/information or engine testing results. We didn’t build these complicated vehicles; we
just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the
vehicle either, so it may take a few replies to get to satisfactory results. Note there may be an issue where the complexity of the issue will require a Premium Service. This service will be an addition to the normal question cost. Usually it does not come down to this but keep in mind!! I am also going to direct you with the fastest, easiest and most common things to check first. Please be
patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in
return. I will also continue assisting you after you have rated me, if necessary. If there
is any reason I cannot get a positive rating, please let me know why “in advance”, so I
can go another direction for you. I am sorry you’re having this problem; I’ll help you
through it.
Below is my first answer or request for more information. If you do not understand it, or you need more information from me, or need me to go in more detail.

what was the hc, co, co2 and o2 readings if you have it?

did you adjust the mixture screws of the carburetor?

please do let me know

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