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Loud secondary air pump

29495 Views 65 Replies 12 Participants Last post by  vaboxr
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.
21 - 40 of 66 Posts
Thanks DHoang,

Good idea on soaking the airvalve :thumbup:. I may try that tonight.

I would replace the air valve in a heart beat if I know for sure it will solve my chu chu train noise problem. The last time I checked for price was 110 buckaroos, that's a lot of money to throw away.

seafoam madness
Don't worry I won't go the brake booster route.
I will probably go via the air valve inlet.
Update,

So, I have been hitting my SAP with Seafoam about a 1/4 of the bottle each time early in the morning to ensure the SAP will kicking.
Start the car up, nice cloud of white smoke out of the tail pipe and a whip of stinky diesel aroma, off I went for a ride to burn up the seafoam while bring the cats to temperature.

It has been three times and 3/4 of the Seafoam bottle later and here is my impressions
- The audible chu chu train sound of the SAP has definitely improved.
- The exhaust out of the tail pipe is not as smelly as it used to be. I considered this is a bonus since I didn't expect any thing.

I will probably get another bottle once this one run out.
So what do you think folks?
Not sure what exactly the Seafoam is doing to what but if it works, what the heck! FWIW, I had multiple (3 total over 4 years) SAP failures in my previous e39. This one has no issues over 2 years. :dunno:
The Seafoam thing is supposedly remove carbon deposits wherever it touches, there's ton of people out there really believe in them. I'm one of those that is reluctant, but what the heck! is the correct term for me too.

If this ever turned out to be the fix for my chu chu train sound! I will make seafoam as a part of my SAP passage routine maintenance.
Not sure what exactly the Seafoam is doing to what but if it works, what the heck! FWIW, I had multiple (3 total over 4 years) SAP failures in my previous e39. This one has no issues over 2 years. :dunno:
Even if it doesn't fix your problem, consider valve replacement as preventive maintenance. They can and do fail. I had one fail at around 35k miles under warranty. When I hit 120k I went ahead and had a new one installed.

Interesting about your results with Seafoam. It is supposed to reduce intake deposits on valves and such. I run a can of Lubro Moly "Ventil Sauber" in my gas tank every 5k miles or so. When I had my valley pan gaskets replaced the tech said my intake system and the ports into the intake valves looked really good.
Thanks DHoang,

Good idea on soaking the airvalve :thumbup:. I may try that tonight.

I would replace the air valve in a heart beat if I know for sure it will solve my chu chu train noise problem. The last time I checked for price was 110 buckaroos, that's a lot of money to throw away.

Don't worry I won't go the brake booster route.
I will probably go via the air valve inlet.
Final update

This morning the ambient temperature is about 25 degree F.
Started the car. No more chu chu train or fast thumping sound. After all these years it's finally fixed.

The credit goes to E46Fanatics though! Here is picture I got from them.

Attachments

Glad to hear !

So what exactly is this Seafoam supposed to be cleaning when it's poured down that large hose?

Looks to me like if I poured Seafoam down this hose on my '98, it'd go down directly to the pump, would it not?

I think the part needing a Seafoam cleansen is the valve itself, isn't it?
DHoang,
Make sure the engine is cold early in the morning to ensure the secondary air pump will kick in.

Just pour about a 1/4 of the seafoam or less then re-attch the hose.
Start the car, let it idle for 15 minutes, go for a ride to burn off.

Yes, when you pour the seafoam it would go down to the motor, but no big deal once the motor kicks in, all will be evacuated into the air valve, exhaust passage, and some will go to the intake manifold via the smaller vacuum hose.

I will be doing this to all my cars as a preventive maintenance. You wouldn't believe how quiet my SAP now :thumbup:
Glad to hear !

So what exactly is this Seafoam supposed to be cleaning when it's poured down that large hose?

Looks to me like if I poured Seafoam down this hose on my '98, it'd go down directly to the pump, would it not?

I think the part needing a Seafoam cleansen is the valve itself, isn't it?
stirring up old thread......

16valex, how are things with your SAP nowadays?

I noticed my pump a few times (many months ago) to be quite noisy on -some- occasions, not always (more of a loud electrical buzz than a choo-choo), but in recent months I've heard nothing from it. Maybe it is dead...

My car starts fine, runs fine, no CELs, nothing ... but the silence is worrisome. Time to diagnose but wanted to get some clarification with the Seafoam.

If you are running Seafoam through the valve, does it go straight into the cats (ex. manifold) and out the exhaust? Or into the cylinders/valvetrain at all?
I did not save the soul of the SAP with Seafoam, it went belly up like a puffer fish out of water, I since replaced it with new one.

You're probably right with your SAP, your SAP is giving you the silence treatment which is not good in this case.

I assuming it goes straight to exhaust, but not 100 percent sure..
16valex, how are things with your SAP nowadays?

I noticed my pump a few times (many months ago) to be quite noisy on -some- occasions, not always (more of a loud electrical buzz than a choo-choo), but in recent months I've heard nothing from it. Maybe it is dead...

My car starts fine, runs fine, no CELs, nothing ... but the silence is worrisome. Time to diagnose but wanted to get some clarification with the Seafoam.

If you are running Seafoam through the valve, does it go straight into the cats (ex. manifold) and out the exhaust? Or into the cylinders/valvetrain at all?
Uh-oh!

I just went out and unplugged the fat plastic hose between the SAP and the valve. It has no major residue.

I will test the relay with a 12v source, and may try to clean the checkvalve (possible?) and dissect the pump. I have a new bearing that I bought sometime ago, time to go read CN90's rebuild thread again ....
This morning it was about as cold as it usually can get here in wintertime, just below freezing. I unplugged the pump hose from the diverter valve and cranked the car.

The flow from the pump is very strong and steady but the pump itself I cannot hear over the engine.

The diverter valve inlet has vacuum, but it is not anywhere as strong as the air blowing out the pump hose.

I suppose this means time to replace the valve. Thing sure looks clean and shiny but it's probably 12.5 years old.

My other car wants a battery.... I'm about ready to join a monastery, too much material controlling my life. :mad:
Pete, sounds to me your SAP is working orderly. The diverter valve's vacuum just enough to open the valve to let the air into the engine. I would not do a thing to it..
This morning it was about as cold as it usually can get here in wintertime, just below freezing. I unplugged the pump hose from the diverter valve and cranked the car.

The flow from the pump is very strong and steady but the pump itself I cannot hear over the engine.

The diverter valve inlet has vacuum, but it is not anywhere as strong as the air blowing out the pump hose.

I suppose this means time to replace the valve. Thing sure looks clean and shiny but it's probably 12.5 years old.

My other car wants a battery.... I'm about ready to join a monastery, too much material controlling my life. :mad:
Hummm well .... I guess I assumed the diverter valve vacuum should be a bit stronger.

Anyone around here ever autopsied these valves? Is the diaphragm itself some sort of metal material? I was intrigued by your (16valex) use of Seafoam on it. I've used Seafoam on a lawn mower but never in a car, and I'm still not clear on where exactly the air from the diverter valve is being sent....
Pete, sounds to me your SAP is working orderly. The diverter valve's vacuum just enough to open the valve to let the air into the engine. I would not do a thing to it..
I have an old valve lying around but can't find it now. The diaphragm of the diverter (check) valve must be metal as it must withstand hot exhaust gas. When the electric valve draws a vacuum on the check valve, it opens the diaphragm. Simultaneously, the SAP is activated and pumps air into the exhaust stream to enhance combustion of unburned hydrocarbons in the cats. The vacuum ends when the pump shuts down and closes the valve.
Hummm well .... I guess I assumed the diverter valve vacuum should be a bit stronger.

Anyone around here ever autopsied these valves? Is the diaphragm itself some sort of metal material? I was intrigued by your (16valex) use of Seafoam on it. I've used Seafoam on a lawn mower but never in a car, and I'm still not clear on where exactly the air from the diverter valve is being sent....
When the valve fails, is it something akin to the diaphragm burning through?
I believe there is a spring inside the valve. The vacuum simply overcomes the spring tension and opens the valve. When the vacuum ends, the spring closes the valve. Pretty simple. I believe the problem is with carbon buildup in the valve. It is exposed to the constant exhaust stream on one side, which is full of contaminants. These build up over time and eventually cause the diaphram to jam in the open position. This then allows hot exhaust gas into the pump, which condenses into water, drips down into the pump and kills it. That is why periodic (every 8-10 years) replacement of the check valve is good preventative maintenance. The pump only runs for a minute or so every cold start so it should last the life of the car. Only when the check valve fails does the pump fail.
Is it correct that the air going into the valve is being directed into the cylinders to produce a lean combustion state? Or is the air being pumped directly into the exhaust manifold to help protect the cats from overly rich exhaust emissions? If the former, does the system on these inline-sixes also fail due to carbon buildup?

Look at these pics from the m5board....

http://www.m5board.com/vbulletin/e3...-system-carbon-build-up-removal-pictures.html
Neither. The injected air is used to increase combustion of unburned hydrocarbons. This link gives the best explanation to date as to why there are excess hydrocarbons.
http://www.bimmerfest.com/forums/showpost.php?p=6519023&postcount=8

It followed my link, which was based on a TIS bulletin.
http://www.bimmerfest.com/forums/showpost.php?p=6519020&postcount=7
Is it correct that the air going into the valve is being directed into the cylinders to produce a lean combustion state? Or is the air being pumped directly into the exhaust manifold to help protect the cats from overly rich exhaust emissions? If the former, does the system on these inline-sixes also fail due to carbon buildup?

Look at these pics from the m5board....

http://www.m5board.com/vbulletin/e3...-system-carbon-build-up-removal-pictures.html
fudman, do you think this SAS could be impacted by carbon deposits? I saw the m5 engine photos and wondered if the system on these i6 engines could have the same problems? Or if carbon deposits or clogging could kill the valve and pump.
Neither. The injected air is used to increase combustion of unburned hydrocarbons. This link gives the best explanation to date as to why there are excess hydrocarbons.
http://www.bimmerfest.com/forums/showpost.php?p=6519023&postcount=8

It followed my link, which was based on a TIS bulletin.
http://www.bimmerfest.com/forums/showpost.php?p=6519020&postcount=7
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