Secondary air pump always running

[BrianKK]

2000 M Coupe.

My secondary air pump is always running - never stops until I turn off the car.

I occasionally get (and clear) fault codes for it as well.

Any idea why it would run constantly?

[Blacklane]

Could be a stuck relay.
See Post #16 in this thread for a description: http://forums.bimmerforums.com/forum...ndary-air-pump
Just pull it out and see if the pump stops.

[Craig in Alabam]

http://www.bavauto.com/newsletter/20...newsletter.pdf

If you haven't seen it already, there is a good article here on diagnosing the SAP. It may help you figure that out.

I also got the P1423 code recently, but my SAP checks out good and runs and stops when it should. I still have the CEL though.

Cheers!
Craig

[luciano136]

The relay should be the first thing to look at. If broken or stuck, it indeed won't turn off the pump.

[BrianKK]

Thanks for the tips, all.

As luck would have it, work is pulling me out of town for the next week, so this will have to be put on hold. I'll have a look at that relay when I get back.

Thanks for the suggestions.

As an aside -- I just purchased this car. What a hoot!

[Blacklane]

http://www.bavauto.com/newsletter/20...newsletter.pdf

If you haven't seen it already, there is a good article here on diagnosing the SAP. It may help you figure that out.

I also got the P1423 code recently, but my SAP checks out good and runs and stops when it should. I still have the CEL though.

Cheers!
Craig

P1423 with no other codes is almost always a vacuum leak. Check for leaking or broken vacuum hoses, particularly the CCV hoses.

[Craig in Alabam]

P1423 with no other codes is almost always a vacuum leak. Check for leaking or broken vacuum hoses, particularly the CCV hoses.

Thanks, Blacklane! I'll check that today.

Cheers!
Craig

[BrianKK]

Finally got a chance to look at the relay. I'm not certain which of the three relays it is, but I checked them all and they all work.

I'll go through the Bavauto procedure this weekend.

If this (SAP being on all the time) rings a bell to anyone, feel free to chime in.

[Kyle Anderson]

I had the same issue with my 1.9, and it was a crack in the plastic hose going to the SAP. There was considerably more noise than usual though. Not sure if this is the case for you.

[BrianKK]

So I worked a little bit more through this last night.

Turns out the SAP is *not* always running. The noise I heard is some other fan in that same area (inside the long, narrow, tall, captive-screwed black box sitting just to the outside of the SAP). I only realized this after removing the SAP and still hearing that damn fan.

So my SAP isn't running. By the time I discovered this, it was late, so I didn't check to see if it would run when given 12V directly. I'll do that tonight or tomorrow.

I did notice, however: The check valve mostly closes after the engine warms up, but it's not completely closed. If I pull the vacuum line off of the check valve, it closes completely - at least as much as I could tell by putting my hand over the pressure-hose opening & feeling the change in pressure after it warmed up. I wonder if that little bit of "not closed" is causing any problems. I would say it's 90% closed when it's closed.

[Blacklane]

That's the DME cooling fan. It's supposed to run all the time. If it's noisy, replace it.

You need to fix the exhaust leak into the SAP. Many SAPs have been destroyed by that leak. Usually, it's the SAP control valve attached to the exhaust manifold that needs to be replaced.

[BrianKK]

To keep the post updated, the check valve was definitely an issue. After replacing it (which is a snap, as you might imagine - just two nuts and a couple hoses), there's a different sound coming out of the SAP (subtle difference). I have a feeling the check valve wasn't properly opening or closing before - like it was mostly stuck.

No check engine light so far.

Also, thanks for the tip on the DME fan. I'll be on the lookout for one.

[Craig in Alabam]

Also, to update the list on my P1423 code, it turned out to be the gas cap seal. I was afraid to post that because I kept expecting the CEL to come back on. But it's been a couple months and still no CEL, and the gas cap seal is dry.
So I don't have and warning light, and the SAP check valve is working, but the SAP runs for about 2 minutes. This thread reminded me I need to check the relay.

Cheers!
Craig