# How to adjust timing to pass a smog check?



## iansmith6 (Nov 12, 2006)

My 1999 Nissan Maxima will not pass a CA smog check because...

"Timing is at 24°B. Needs to be set to 15°B w/throttle position sensor disconnected."

Anyone know how to do this? Does it require hooking up to a computer or can I just open up the hood and turn a screw or something. Couldn't find anything on doing this for 1999 models.

Thanks!


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## smj999smj (Jan 1, 2006)

Ignition timing is non-adjustable and controlled by the ECM.


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## iansmith6 (Nov 12, 2006)

How can it not be adjustable? I can't drive my car until this is fixed because it won't pass inspection.


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## 4thGenTinkerer (Nov 1, 2009)

The timing is regulated by the ECU. This means there is no way to advance or retard the timing yourself. Your car is running too rich, or too lean. I would start looking into why the thing isnt running like it normally should.
Is your check engine light on?
Have you pulled the codes?- Most parts stores have an OBDII code reader they will lend you or they will pull the codes for you in the parking lot.
Write these DTC's (Diagnostic Trouble Codes) down and post them in this thread and I will tell you what is wrong with your car.
Good Luck and welcome to NF.com.


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## iansmith6 (Nov 12, 2006)

Ahh, I see. I have an ODBII reader and it says no codes. Engine light is not on. 

Only thing on is my airbag light which is another issue entirely I need to eventually deal with.

I guess I need to take it to a Nissan shop and pay money for them to poke it until it works right again.


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## rogoman (Dec 16, 2004)

iansmith6 said:


> My 1999 Nissan Maxima will not pass a CA smog check because...
> 
> "Timing is at 24°B. Needs to be set to 15°B w/throttle position sensor disconnected."
> 
> ...


There is no external adjustment to set the ignition timing; it's all done by the ECU. In your case, there could be several reasons for the timing to be off:
- The crank angle sensor is defective.
- One or both cam angle sensors is defective.
- The timing chain may have a problem.


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