P0491 secondary air injection insufficient flow bank1 only

[pparra]

Hi 

After a complete rebuilt I have the P0491 on bank one only.

Any suggestion?

[JFP in PA]

7 minutes ago, pparra said:

Hi 

After a complete rebuilt I have the P0491 on bank one only.

Any suggestion?

 

Welcome to RennTech

 

These types of issues are typically the result of mechanical "plugging" of the SAI ports on the bank in question.  During the rebuild, did you have the heads done by a reputable shop, and did you blow out the SAI passages prior to assembly?

[pparra]

Hi JFP, Thank you for your answer.

Sorry I turned in wrong information, I ddi not read my ODB scanner correctly, I have both P0491 and P0492 not just one bank, now I understand better what to check starting from the air pump that I am sure pump is blowing strong, I think next I need to check the air line going to the check valve but if you have any suggestion on what kind of test I can do I will appreciate.

Yes head job was done very well by a shop specialized on this kind of head, the SAI passages are cleaned and polished, double checked that during assembly.

Thank you 

 

  

[Ahsai]

These codes have been covered here many times so there should be some material if you search a bit.

There is a changeover valve when activated will allow vacuum to be routed to activate the SAI physical valve, which lets the SAI pump air into the heads. So basically you need to check the operation of the changeover valve, make sure all the vacuum tubes are connected, the vacuum reservoir has no leaks, and then finally the SAI physical valve is working. Most of the cases are either the changeover valve or some disconnected vacuum tubes.