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Discussion Starter · #1 ·
My secondary air pump saga continues.

Valve works and hoses are fine. I have checked the circuit and there is electricity at the pump connector. Consequently, I have a bad air pump (again!). I did a check of my repair records and the air pump and valve has been replaced previously under warranty. That means this is the third secondary air pump failure in four years! Seems like a trend. I have reordered a new pump but wonder if I am doomed to replace my pump on an annual basis.

Inspection of the defective air pump reveals no water inside. Hence, the valve is not the culprit. I suspect the cause may be electrically related. Are there any other potential causes of an air pump failure? Could a bad relay be the problem? What causes the air pump to shut off? If it fails to shut off, could I be getting a pump burnout? :dunno:

Just wondering if any other people with repeated air pump failures have any insight into the cause.
 

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We do sell alot of them but 3 in 4 years is high, I do not know where it is but I had a tech sheet that stated some were failing due to moisture freezing inside; I would have thought that this issue would have been thought of in the design though.
 

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what is a secondary air pump, is it the same was a Fuel Tank Breather Valve?? I have replaced one of those before...
Emission control, it is in the engine compartment.

Mine was replaced under warranty at around 35k miles in 2004. Bad check valve caused the pump failure.
 

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My secondary air pump saga continues.

Valve works and hoses are fine. I have checked the circuit and there is electricity at the pump connector. Consequently, I have a bad air pump (again!). I did a check of my repair records and the air pump and valve has been replaced previously under warranty. That means this is the third secondary air pump failure in four years! Seems like a trend. I have reordered a new pump but wonder if I am doomed to replace my pump on an annual basis.

Inspection of the defective air pump reveals no water inside. Hence, the valve is not the culprit. I suspect the cause may be electrically related. Are there any other potential causes of an air pump failure? Could a bad relay be the problem? What causes the air pump to shut off? If it fails to shut off, could I be getting a pump burnout? :dunno:

Just wondering if any other people with repeated air pump failures have any insight into the cause.
Here is what you should have done first :

1)Activate the pump by applying power and ground to it.
2)If it operates,check the air output and determine wether it is strong enough to open a valve (non-return valves are sprung closed). Another option is to use a paper clip and locate the small pinhole on the (surface/top) non-return valve.With the pump activated and the supply hose is attached to the valve,insert the paperclip and feel for any change in depth.When activated and the non-return valve opens you should feel a difference.If nothing changes when the paperclip is inserted,the air output is weak and you would need a new pump.
3)Inspect the non-return valve for any carbon deposits by inserting a rag (preferrably clean so you can tell the difference). If deposits are found,there is a good chance thse deposits causes the valve to bind.This valve is succeptible to moisture and all the other elements therefore would stick like and idle valve.
4)If the pump and the non-return valve operates properly by performing the tests and the pump is still INOP when cold causing the Service Engine Soon lamp to come on,replace the relay P/N 12 63 1 742 690 (salmon in color which I believe happens to be located in the E-Box where the DME resides). This is usually the cause of failure in operation of the system.

These vehicles are a little easier to diagnose and does not have the problems other series and engine variants has.For example the M62TU and the S62 has been known to have clogged secondary air delivery passages within the cylinder heads.BMW states one of the causes :

Excessive combustion chamber/exhaust manifold deposits may be attributed to usage of fuels with inadequate level of detergents. BMW recommends exclusive use TOP TIER Gasoline to prevent an excessive deposit build-up.

If clogged,cylinder heads require removal and disassembly in order to clean the passages.Covered under the terms of the BMW New Vehicle Limited Warranty but can be costly when out of warranty.
 

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Discussion Starter · #12 ·
Here is what you should have done first :

4)If the pump and the non-return valve operates properly by performing the tests and the pump is still INOP when cold causing the Service Engine Soon lamp to come on,replace the relay P/N 12 63 1 742 690 (salmon in color which I believe happens to be located in the E-Box where the DME resides). This is usually the cause of failure in operation of the system.

These vehicles are a little easier to diagnose and does not have the problems other series and engine variants has.For example the M62TU and the S62 has been known to have clogged secondary air delivery passages within the cylinder heads.BMW states one of the causes :

I have checked the voltage at the air pump and it's fine. The valve has been replaced with the two previous pump replacements. It is operating correctly at startup. I think you may be right abouyt the relay. Is there a test for proper relay function?

I have the Service Tech Memo. It talks about the Top Tier Gas but there is no significant carbon buildup at the valve.

The memo (& Bentley's) states that the air pump should turn off after two minutes max. I intend to verify this when I get my replacement pump (or I can watch the voltage). My only remaining hypothesis is that the relay is not shutting the air pump off after two minutes causing it to burn out prematurely. Has this ever occurred to anyone?

Thanx for all the feedback.
 

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Here is what you should have done first :

4)If the pump and the non-return valve operates properly by performing the tests and the pump is still INOP when cold causing the Service Engine Soon lamp to come on,replace the relay P/N 12 63 1 742 690 (salmon in color which I believe happens to be located in the E-Box where the DME resides). This is usually the cause of failure in operation of the system.

These vehicles are a little easier to diagnose and does not have the problems other series and engine variants has.For example the M62TU and the S62 has been known to have clogged secondary air delivery passages within the cylinder heads.BMW states one of the causes :

I have checked the voltage at the air pump and it's fine. The valve has been replaced with the two previous pump replacements. It is operating correctly at startup. I think you may be right abouyt the relay. Is there a test for proper relay function?

I have the Service Tech Memo. It talks about the Top Tier Gas but there is no significant carbon buildup at the valve.

The memo (& Bentley's) states that the air pump should turn off after two minutes max. I intend to verify this when I get my replacement pump (or I can watch the voltage). My only remaining hypothesis is that the relay is not shutting the air pump off after two minutes causing it to burn out prematurely. Has this ever occurred to anyone?

Thanx for all the feedback.
Fudman were you able to fix this and learn why it failed so frequently?
 

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Replace the ENTIRE system... everything, including relays and fuses. That is the only way I got mine to finally behave after 3 or 4 dead parts in 2 years. Good luck.
 

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Discussion Starter · #17 · (Edited)
Fudman were you able to fix this and learn why it failed so frequently?
I was able to implement a very simple and effective permanent fix but never got to fully understand why I had repeated SAP failures. I TOTALED the car! Fortunately, they hit me so this "fix" did not cost me anything. This is not recommend corrective action for people with SAP issues but it worked for me. I have had my "new" e39 for almost two years and 18K miles and have nary a problem with the SAP.

BTW:
On the previous car, the dealership gave me a new SAP under the parts warranty (it was less than 1 year old when it failed). I simply replaced the SAP and was waiting for it to fail again when the car was totaled 9 mos later.
 

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I was able to implement a very simple and effective permanent fix but never got to fully understand why I had repeated SAP failures. I TOTALED the car! Fortunately, they hit me so this "fix" did not cost me anything. This is not recommend corrective action for people with SAP issues but it worked for me. I have had my "new" e39 for almost two years and 18K miles and have nary a problem with the SAP.
wow good to hear that the "new" is doing well
 

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