1981 Toyota Pickup Cold Rough Idle

1981 TOYOTA PICKUP
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81TANTOY
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Hi there. I have an 81 toyota 4x4 pick up with 150,000 org. miles. It recently had that carb. rebuilt and adjusted to pass CA smog. This took place in the LA area but now I am in the cental valley (Fresno). The problem that I am haveing is it runs rough, won't idle, and smokes (black) when cold. Once warm it runs great. This Truck has been taken very nice care of so the vacc. lines seem to be all in good shape. It does seem as though the catalytic converter might be going out (there is a slight sulfer smeel) and the O2 sensor needs to be replaced. I was thinking that I need to fix the cold runing issue first to advoid the burning out of the smog stuff, but could that be the problem?

thanks for hearing my ploblem
please help
josh
Aug 21, 2006 at 9:39 AM
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MIKEYBDMAN
  • ✓Experienced Mechanic
  • 623 POSTS
[quote:797827840f="81tantoy"]Hi there. I have an 81 toyota 4x4 pick up with 150,000 org. miles. It recently had that carb. rebuilt and adjusted to pass CA smog. This took place in the LA area but now I am in the cental valley (Fresno). The problem that I am haveing is it runs rough, won't idle, and smokes (black) when cold. Once warm it runs great. This Truck has been taken very nice care of so the vacc. lines seem to be all in good shape. It does seem as though the catalytic converter might be going out (there is a slight sulfer smeel) and the O2 sensor needs to be replaced. I was thinking that I need to fix the cold runing issue first to advoid the burning out of the smog stuff, but could that be the problem?

thanks for hearing my ploblem
please help
josh[/quote:797827840f]

If you know your O2 sensor is bad, I would replace that first. then if you still have a rich condition at idle, I would correct that problem.
Aug 21, 2006 at 10:17 AM
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Suggested Repair

Replace the oxygen sensor first if it is known to be bad. If a rich idle condition remains afterward, correct that rich condition.

Conversation Summary

The owner of a 1981 Toyota 4x4 pickup reports rough running, no idle, and black smoke when cold after a carburetor rebuild and smog adjustment; it runs well once warm. The owner suspects a failing catalytic converter and a bad oxygen sensor. The expert advises replacing the oxygen sensor first, then correcting any remaining rich idle condition.

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