Adjusting CO on a 3.2 engine

[ljowdy]

I read in Wayne's 101 book that on occasion it's necessary to re-set the CO and Idle on a 3.2. I was just wondering how often this is necessary???

[yelcab1]

Not once in my 10 years with the Carrera, which I don't have anymore.

[DRACO A5OG]

After replacing my CHTS, ICV I had the Idle checked to insure proper settings. I have to go to a smog check shop to test the CO readings

[ianc]

Not a bad idea to at least have it checked once a year. If it's fine, leave it, if it's changed, it may be normal due to expected engine wear, or it may clue you in to some developing problem,

ianc

[917]

Hi !

Like most things in life, if everything was produced exactly the same, never started to wear, was never altered or modified and operated in the same environment then nothing would ever need to be adjusted. But....

So, it's a good idea to correctly (with a gas analyzer or wide-band oxygen sensor) check your mixture setting since these car are around 20 years old and have not only experienced a certain amount (no matter how small) of wear over those years along with possible changes and mods by previous owners.

Even if the engine has been "refreshed" other components such as the AFM (air flow meter), throttle shaft, hoses, injectors etc can all have slight amounts of wear which can affect the mixture. Of course, it goes without saying that any modifications such as an exhaust upgrade, oversize pistons or even an air intake change will have an affect.

Another factor is air temperature and density which could have a slight affect if the mixture had been set for a different location's environment.

I would suggest if you are concerned, have it checked (properly) to put your mind at rest, but then unless you have idle quality problems in the future or make some changes of your own, you shouldn't have to worry about it again for quite a long time (maybe 20 years !...lol). That is, unless you have to have it checked for registration purposes.

Anyway, hope this helps. Cheers !

Chris

[ljowdy]

Thanks for the replies.

My friend has the 3.2 and worries about everything.

In fact some of his worries are contradictory in nature. One minute, he wants to check is CO for accuracy but in the same breath, he doesn't, because he believes that the 02 sensor will correct any emission problems.

note: I have volunteered to check and adjust his CO using my Gunson's Gas Analyzer but so far, he has resisted because he unrealistically believes that it's intrusive.
(my god, it's not a colonoscopy)

I tried to explain that it's mechanical and anything mechanic is subject to failure or in this case adjustment.

This information is exactly what I need to show him..

[stlrj]

Originally Posted by ljowdy

"...he believes that the 02 sensor will correct any emission problems."

The 02 sensor can only make small corrections but will not be able to compensate if too far out of spec.