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Discussion Starter · #1 ·
My 97-528 SAP is kind of loud compares to my 02-530.
It's a fast loud thumping sound.
I think the air passage may have been clogged, but then again this maybe normal for 528.
How's every 528 SAP sound in the morning? Thanks for the feed back.
 

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I can't speak from experience with a 528 but a SAP should not have a "fast thumping sound". It should be very similar to your 530, where you can hear it if you are listening to it but it is strictly background noise. Your check valve could be failing or your pump could be failing. I would check both.
 

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Discussion Starter · #3 ·
It's definitely louder than my 530
The pump and air valve were replaced at the same time about a year ago
The sound exist before replacement of both valve and pump
Reason to replace was CEL
Car has no CEL at themoment.
I think the orifice inside the exhaust manifold is partial clogged.
I think I need to find a way to clean the carbon build up inside the exhaust manifold.
 

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Discussion Starter · #5 ·
I'm not sure if that is your problem as it should generate a code and the symptoms don't align with that problem. Anyway, here is the BMW TIS for that problem: http://www.bmwtis.net/tsb/bulletins/bulletin_graphic_temp/B110504g.htm
Thanks Fudman, that's a lot of work.

But here is my plan to diagnose.
Disconnect the output hose to the pump and turn it on and see if the noise still there or not. And depends on the outcome of this test, I will have a better idea.

Thank you.
 

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I think I just had my SAP issue figured out. I was getting codes for low air for secondary pump and it was very loud. I replaced the tube that goes from the pump to the valve, issue persisted. I then replaced the vacuum hose connected to the valve which got baked since it was routed above the exhaust manifold. Whoever designed that should be shot. I also replaced the salmon colored relay in the E-box. It's the 3rd day and the code has not come back.
 

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Discussion Starter · #7 · (Edited)
I think I just had my SAP issue figured out. I was getting codes for low air for secondary pump and it was very loud. I replaced the tube that goes from the pump to the valve, issue persisted. I then replaced the vacuum hose connected to the valve which got baked since it was routed above the exhaust manifold. Whoever designed that should be shot. I also replaced the salmon colored relay in the E-box. It's the 3rd day and the code has not come back.
Good job figuring out your problem there bud!
How about the loud noise? did it go away too?
Please reply. TIA.

PS. The salmon color relay location is it in the box under the micro filter housing?
 

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The pump is sooooo much quieter now. I have a feeling that between the vacuum leak and the relay ( not opening the valve), the pump was having to work much harder. I used to be able to hear it over the motor and possibly the next neighborhood over.

Yes, it's under the cabin filter housing(driver side) which easily comes off. It's the only salmon color relay and P/N 1263742690 ($14 from dealer).
 

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Discussion Starter · #9 ·
The pump is sooooo much quieter now. I have a feeling that between the vacuum leak and the relay ( not opening the valve), the pump was having to work much harder. I used to be able to hear it over the motor and possibly the next neighborhood over.

Yes, it's under the cabin filter housing(driver side) which easily comes off. It's the only salmon color relay and P/N 1263742690 ($14 from dealer).
Thank you BentValve for getting back with me on this info.
Yeh! my SAP is really loud, I'm hoping to find a clogged vacuum line to the air valve, this would explain the fast thumping (whooshing, chu chu train) sound.

If the above doesn't then I will look into the relay. Thanks again.
 

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Yeah check the little things first. Your pump should be fine if it still turns on, chances are the valve is fine too. The vacuum hose that goes from the valve to the electric air valve is more than likely rotted. Replacing that was the hardest because the electric air valve is under the intake manifold. I basically just had to feel around there to put the new hose on.

In my case, I'm not sure if it was the vacuum hose or the relay, I replaced both to be on the safe side. I still have the relay which may or may not work if you want it.
 

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I don't think your vacuum line would be clogged but it may be cracked, leading to a leak, which could then result in insufficient pressure to fully open the check valve. The backpressure against the pump could be that sound you are hearing. I would check the section of the vacuum line between the thin plastic pipe that runs parallel to the engine and the check valve. That section of hose is prone to fracture due to the exhaust manifold heat. The rear section between the plastic line and the pump is usually fine as it is away from any major heat source.
 

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Discussion Starter · #14 ·
I don't think your vacuum line would be clogged but it may be cracked, leading to a leak, which could then result in insufficient pressure to fully open the check valve. The backpressure against the pump could be that sound you are hearing. I would check the section of the vacuum line between the thin plastic pipe that runs parallel to the engine and the check valve. That section of hose is prone to fracture due to the exhaust manifold heat. The rear section between the plastic line and the pump is usually fine as it is away from any major heat source.
So true:thumbup:. But wouldn't this will cause a CEL? :dunno: Perhaps the valve is partially open just enough to satisfy EML system!!!

Any how, I can't wait for the wife to come home and start tearing the car apart :eeps:

I will be back with an update regardless. Thanks Fudman.
 

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Discussion Starter · #17 ·
Update.

http://www.realoem.com/bmw/showparts.do?model=DD53&mospid=47585&btnr=11_1594&hg=11&fg=45

Since this car is a 97 M52, the vacuum control line is ran around the front, and then under the intake manifold. I remember replaced all the hoses about a year and half ago during the CCV R/R.

- All hoses appeared to be in good shape
- Checked item 11 electric valve functions, it toggled when 12V DC is applied.
- Checked item 14 one-way valve for correct position and blow test passed.

I'm back to square one

1/ Air valve partial clogged
2/ Exhaust passage partial clogged
3/ Pump has water

Tomorrow morning when the engine is cold I will disconnect the inlet hose to the air valve and see if the loud noise changes.
 

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Discussion Starter · #18 ·
Update

- Just dis-connect the big hose goes to the air valve inlet, started the car, no chu chu train nor fast thumping noise, I can feel the powerful air out of this hose. So, the pump itself is fine.

- I also checked the for vacuum during this time from the vacuum line, and yes I felt vacuum.

Now, with the above have been checked and verified.
The remainders are more likely suspect.

- Half clogged air valve
- Partial clogged exhaust passage.

I plan to to take Seaform to this thing. Stay tune.
 

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Good job on isolating the problem:thumbup:

Before you do that seafoam madness, try removing the valve, and let it soak in WD-40 overnight. If the valve is partially sticking mechanically, this soaking will free things up.
If the valve isn't opening up due to other issues, like a diaphragm malfunction, then most likely a replacement is what's needed. :dunno:
 

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16valex,

I wrote the SAS Troubleshooting guide here:
http://www.bimmerfest.com/forums/showthread.php?t=402816

FYI, the BMW TIS recommends that whenever you suspect a bad air valve, the following in that circuit needs to be replaced to avoid further troubleshooting:
1. Air Valve (average life is 100-120K)
2. Vacuum hose to Air Valve and to the Electric Valve.
3. Electric Valve (under Intake Manifold), here is a pic of the Electric Valve:

 

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