Need help with code p0491

[petener999]

My wife 03 x5 4.6is check engine light came on, pulled a p0491 code, secondary air injection bank one. Here is the list of what been done.

1: New secondary air pump

2: New check Valve

3: All new vacuum hoses

4: New MAF seal gasket to elbow

Clear the code, but the SES only comes on during morning start-up.

Thanks in advance.

[Laidback]

Does it only happen in a.m start up?

[petener999]

Thanks for the response Laidback. Yea, only morning start up. Could it be the o2 going south?

[Laidback]

Check connections and thats a code for a bad secondary air pump, double check the on you just replace...Thanks for the response Laidback. Yea, only morning start up. Could it be the o2 going south?

[petener999]

Check connections and thats a code for a bad secondary air pump, double check the on you just replace...

Air pump is new and tested before installation. I will double check with the connection and see what happen... This is driving me NUTS!!!! Thanks again, Laidback:thumbsup2:

[kautiongsr]

first thing make sure that the secondary pump turns on in the morning.. its pretty loud... if it dosnt.. its going to be the relay..
if it turns on.. then i would replaced the diverter valves on the back of the intake manifold.. you will have 2 only replace the affected bank..
i dont think its an 02.. thats not usually the problem
let me know what you find
( secondary air pump on turn on in the a.m.)

[petener999]

first thing make sure that the secondary pump turns on in the morning.. its pretty loud... if it dosnt.. its going to be the relay..
if it turns on.. then i would replaced the diverter valves on the back of the intake manifold.. you will have 2 only replace the affected bank..
i dont think its an 02.. thats not usually the problem
let me know what you find
( secondary air pump on turn on in the a.m.)

I did check the secondary air pump on morning start up, and it's working. Also, a new diverter valve was replaced. Are you talking about the vacuum check valve? I also replaced the non-return valve and the SES still returned. Been chasing this DEMON for awhile now, and it winning. Thank you for your input...

[kautiongsr]

I did check the secondary air pump on morning start up, and it's working. Also, a new diverter valve was replaced. Are you talking about the vacuum check valve? I also replaced the non-return valve and the SES still returned. Been chasing this DEMON for awhile now, and it winning. Thank you for your input...

honestly then.. all it can be at this point is" that your secondary air ports in the head are clogged" which is not causing secondary system to work properly.. there are two ways of fixing this..
1. removed engine head and clean out secondary air ports.. which is a bitch..
2. clean ports with brake cleaner and injector cleaner.. us a pick and try to make all the carbon build up come out... this will take time. be patient.

hope this helps...

[petener999]

Thanks, Kautiongsr. I will try to tackle the job.. Can I use Sea-form?

[kautiongsr]

Thanks, Kautiongsr. I will try to tackle the job.. Can I use Sea-form?

not sure.. i use brake cleaner.. any. injection cleaner.. thats about it.. it brakes down the carbon pretty easy