I have to get my car to pass smog by the end of the month so I can renew my registration currently it won't pass! Because I have a emissions code p1273 bank 1 sensor 1 running lean. So I have been trying to fix this issue for the past 6 months with the help of my Toyota mechanic friend trying to troubleshoot this problem one step at a time first I did the obvious and replaced that O2 sensor, Then replaced the intake manifold gaskets both the upper and lower and properly torqed everything down. Then I listened for air leaks and replaced a few hoses still didn't solve the problem! Please Help!
I have a 04.5 Z manual.

Does anyone have any idea what I can do to get my z to pass smog?
Does anyone know what I can do to fix this?
Please help a fellow Z out!!!

 

Check for exhaust leaks? What mods do you have?

 

I had the same code for about a year after going to HFCs and replaced the upper or 1 sensor in the bank (AF sensor) and it pretty much stays off, but I know my car is a little lean so it makes sense for me.

Another trick that one of the guys at Technosquare told me is to take off the plenum spacer and knock down the car's ability to intake air, helping to keep the lean spikes down under the code's threshold.

Also worset case scenario, with tuning software you can disable a code or two before the smog check gets invalidated.

 

Well the only mod I have is a short ram intake that shouldn't set it lean . Was your code only on one bank? It could be my MAF.but I thought that would set off codes in both banks! If it helps my obd 2 has freeze frame data and bank ones fuel trim was 8.6 and bank2 fuel trim was -4.7 when the code was triggered!
Can u clear the code with odb and then smog before light comes on to pass??

 

Get a smoke test to find the leak. Follow all instructions for the code in the FSM. Clean your MAF (according to posted instructions) just in case -- bank 1 always runs a little leaner due to the plenum design.

 

You might be able to, that code sometimes takes days or weeks to came back, but another short term fix is the put the stock filter back on (kinda a resistictor for less air) and then get a O2 extender bung for the sensor (AF not the actual o2). That will get the sensor out of the direct steam and in theory skews the reading in your favor. The bungs normally go for $5-10 at a Pepboys or Autozone.

 

Thanks for ideas and help guys will try them all tomorrow. I am ordering a new MAF sensor right now.Hopefully that will fix it since I think it might be damaged

 

Find and set your **** back to stock, hell borrow a buddy's! Or,

Move to a cleaner, more reasonable state, hell haven't sat in an emmission booth since I was 11!!!

 

I replaced the MAF checked my fuel injectors for proper resistance replaced all spark plugs and got a CARB legal intake system still my code is on and a automatic smog fail!! Please help what can I do

 

Did you try the extended bungs?

 

Those are not really usable to machine and have air tight seal I have found. I bought the spark plug anti foulers and machined one out but the plug doesn't fit all the way down and would have to use a few washers and then wouldn't be air tight. If u have trick please let me know

 

Never used this make but there are threads and comment of others using them everywhere. There's also a black market item that acts as a dummy AF sensor and only sends the propper signal back to the ECU and that will trick the ECU to turn off the CEL.

http://www.mynismo.com/products/?id=9238

 

You might consider taking the car to a Nissan dealer to have it repaired.

 

One problem with that....

Normally leads to a long list of items being replaced, at your expense, while they figure out what's wrong.