Secondary Air Pump low cost alternative

[m5hoot]

O-rings are your choice. Silicon sealer would work just as well and still allow removal. More suspect is the hose leading from the pump to the valve. It is a very thin-wall and flimsey cheap plastic which can rub your A/C pully and develope a hole.

[dville]

Just removed my Secondary Air Valve....looks pretty crusty inside, doubt if it works. Will test according to BMW TIS bulletin below:

Update: 08/2002
Failure of secondary air system (fault analysis guide)
E34, E36, E38, E39, E46, E52, E53, E31 / M60/1, M62 LEV, M73, M73LEV, S50, S52,
S54, S62, M54, M52TU, M52, M44, M43TU
Complaint: - Failure of secondary air system
- Entry in DME fault code memory "Throughput of secondary air system too low"
- "Check engine" lamp illuminated on US vehicles
Cause: Past experience has shown that the failure of the secondary air system is not attributed to a
component fault in the secondary air pump but rather to the secondary air check valve not
closing/opening or the actuating relay sticking.
- Secondary air check valve does not close:
The secondary air valve is located between the secondary air injection channel (either
integrated in the cylinder head or on the exhaust manifolds) and the secondary air
pump.
The electric valve switches through the vacuum from the intake system for the purpose
of opening the secondary air check valve.
Due to soiling, the electric valve can no longer close mechanically. Consequently, the
secondary air check valve is also no longer closed. Hot exhaust gas constantly flows
through the secondary air check valve thus damaging it and possibly also the
secondary air pump.
- Secondary air check valve does not open:
The secondary air check valve will not open in the event of the diaphragm leaking or
sticking. Consequently secondary air injection does not take place although pressure is
applied by the secondary air pump.
- Actuating relay stuck (sticking of relay make contacts):
After starting the engine, the actuation time of the secondary air pump is from 2.5 to
105 seconds depending on the engine temperature and engine speed.
The relay make contacts sticking or sporadically sticking result in continuous power
supply or impermissibly long power supply to the secondary air pump.
The secondary air pump is not designed for permanent power supply and is operated
up to its destruction.
Affected vehicles:
E31 / M73
E34 / M60 B30
E36 (incl. Z3) / M43TU, M44, M52, M52TU, M54, S50, S52, S54
E38 / M52TU, M60 B30, M62LEV, M73, M73LEV
E39 / M52, M52TU, M54, M62LEV, S62
E46 / M43TU, M52TU, M54, S54
E52 / S62
E53 / M54, M62LEV
Production period: from introduction of the secondary air system
Procedure: Proceed as follows in the case of customer complaint:
- Actuation of secondary air pump via the DIS tester:
- Secondary air pump is not operative:
Check whether voltage is applied at the secondary air pump.
If not:
Check electrical lines and plug connections of the secondary air system and replace the
actuating relay if necessary.
If so:
Replace secondary air pump and actuating relay.
Check whether the secondary air check valve is closed on conclusion of secondary air
injection.
For this purpose:
Visually check the secondary air check valve for dirt/soiling at the pressure hose
connection to the secondary air pump:
No soiling:
No further action necessary.
Soiling (black particles/combustion residue) found:
Replace secondary air check valve and electric valve (= solenoid valve that switches
the vacuum from the intake system through to the secondary air check valve).
- Secondary air pump operative:
Check the vacuum hoses from the intake system to the secondary air check valve as
well as the pressure hoses and pressure lines from the secondary air pump to the
engine for leaks and correct installation:
If necessary, replace or correctly install leaking lines, leaking or bent hoses.
No fault found in lines or hoses:
In this case, the secondary air valve is stuck or its diaphragm leaking and therefore
does not open.
Replace secondary air check valve.

[dville]

I removed the plastic part of the secondary air valve, and soaked the insides in PB blaster






Here I stuck my little finger in the valve outlet, then suck on the small vacuum inlet and confirmed that the diapragm moves with vacuum and releases when I stop sucking.

[dville]

Cleaned up secondary air piping. I have new o-rings to install on the pipe..

[m5hoot]

I understand that buying new is always the "easy" way out and applaud you for digging in your heels and attempting to repair and give new life to something old, but still useful (did someone say my name!), but I wonder in this case the long-term wisdom of the PB Blaster route.

I have that stuff and it is a life saver that PS blaster, but I never would have thought to use here. I guess I don't know why not either. I think my concern is that if this valve is original to the car, given the rough service of the constant heat/cool cycle that the diaphram goes through- whether I would still be looking for a new one with fresh rubber? You could argue that the extinguishing of the SES light is the proof of the pudding, but often the system will not give you an error code until the pump quits and then it can be too late. The Saab pump certainly now gives us a 1/3 cost alternative that will work in the existing mounting ring.

Good luck and for sure you have a great insight now into exactly how this whole POS system "works". It is always going to be one of the German's greatest engineering feats for relieving dollars from the American wallet. I make it rather personal because the same system exists on European versions of the same cars, but when the system fails it will NOT even set the SES light. It will set a "soft code" that can be read on a normal scan, but other than than the driver would never know if their pump had quit! Maybe I should blame our EPA, but the system could be made to not alow the pump to accumulate condensation for mere pennies.

Good Job!

[Strahan]

Didn't feel like starting a new thread for this, so I'll just post here, heh. Will the V12's SAP work in the V8? Thanks.

[TxDarth]

I thought this pump looked familiar - noticed on the one post that they also make the one used on the Volvo V70. I had this fail twice on mu '98 V70 R wagon. It is kn ow as a high failure item blamed on location and the SAS valve going bad and allowing moisture to back up in the pump - not to mention it is mounted low again, below the battery on the Volvo. It was over 300.00 each time with the SAS valve.

On the older American iron it is the mechanical pump(driven with the fan belt) that clogs up and rusts - but it is only $40.00 item rebuilt.

Excellent post tho - very good info and welcome aboard.

[m5hoot]

I thought this pump looked familiar - noticed on the one post that they also make the one used on the Volvo V70. I had this fail twice on mu '98 V70 R wagon. It is kn ow as a high failure item blamed on location and the SAS valve going bad and allowing moisture to back up in the pump - not to mention it is mounted low again, below the battery on the Volvo. It was over 300.00 each time with the SAS valve.

On the older American iron it is the mechanical pump(driven with the fan belt) that clogs up and rusts - but it is only $40.00 item rebuilt.

Excellent post tho - very good info and welcome aboard.

Just as a very small clarification...I'm not sure what the pump being mounted lower than the battery has to do with anything, but the failure of the valve is the #1 mode of failure, but not because it lets moisture through to get into the pump. It allows hot gases to pass through and hit a cold pump which forms condensation inside pump which really is different that moisture passing through the valve into the pump. Then height might matter, but it is hot gas that is the issue and not travelling moisture. The other mode of failure is the pump running for excessive time. Pump is over-driven like crazy and it can only last pulling lots of amps for maybe 3-4 minutes tops. If the relay carrying 35-40 amps intermittently at start-up has its contacts stick and the pump run for say 5 minutes, it's toast. If you are lucky enough to have power to the relay and NOT have to go searching for fuse #107, then I would replace the $10 relay, $15 cheapo hose (rubs against A/C pulley and hole developes), pump (use Volvo Pierburg for $107 new), and then the valve at about $110.
BTW, pump should not run under normal conditions for moreb than 110 seconds.

Anything short of this may get you FTW, but I would not want to pay for this POS system more than once.

[TxDarth]

Just as a very small clarification...I'm not sure what the pump being mounted lower than the battery has to do with anything, but the failure of the valve is the #1 mode of failure,

Anything short of this may get you FTW, but I would not want to pay for this POS system more than once.

I mentioned this as it mounted low in relation to the source of the exhaust - this allows the moisture to gather in the pump itself causing the failure in both the BMW and Volvo applications. If the pumps were mounted somewhere higher maybe it would not allow for the moisture to accumulate in the pump. As stated - under the battery which on the Volvo is directly behind the headlights, is quite low just like on the BMW.

[m5hoot]

I mentioned this as it mounted low in relation to the source of the exhaust - this allows the moisture to gather in the pump itself causing the failure in both the BMW and Volvo applications. If the pumps were mounted somewhere higher maybe it would not allow for the moisture to accumulate in the pump. As stated - under the battery which on the Volvo is directly behind the headlights, is quite low just like on the BMW.

Well, heat rises so unless you can get it lower than the exhaust system which would be near impossible, I think that you will find that the exhaust pressure will always keep positive pressure against the SAP valve. The problem is when carbon, rust, soot, and the like build-up in the valve keeping it from closing off all the way when the ECU tells the valve to close at the same time it tells the pump to quit, the same pressure you feel if you try and put your hand over a tail pipe with car running is also pushing against what *should be* a closed SAP valve. If the valve is not fully closed then some amount of warm exhaust gases will be present in the pump causing condensation to form inside the pump leading to bearing failure (usually) from rust.

If the valve is open and the pump is running as it is during about the first 90 seconds after a cold start, the pressure generated by the pump is sufficient to easily overcome the exhaust pressure and force fresh air into the exhaust rather than any exhaust pushing its way toward the pump. These pumps put out a helluva lot of air and have plenty of pressure so exhaust gas going the wrong way will not happen unless the pump is told to shut off and the valve stays open even a little bit. That little valve has a pretty big job holding back constant exhaust pressure.

[dville]

OK, I mentioned that my Check Engine Light was still comming on intermittently.
I just stopped resetting it.
Then I decided to take the secondary air pump from my X5 4.4i just to see if by chance that the pump I got from the junkyard was somehow not blowing as hard.

Took out the X5 air pump:



This is the X5 pump I am about to install


Taking out the VW pump I noticed the exhaust hose had a crack in it.


See hose broken in some sections while I took the pump out.



Removing the hose from the clip next to the AC compressor


Used electrical tape to wrap the broken sections back together.



While installing it the hose cracked in another spot. More electrical tape.


I re-Installed the VW/Audi pump and reset Check Engine Light.

Will report back.

[cazal740i]

i had same issue with my secondary pump....I had the SES light on for two months. I had several codes tho. Cylinder misfire and codes that pointed out to both bank 1 and bank 2 -Secondary air pump..... They were seperate from each other. So I tackled the pump 1st..Was it sucking enuff air to heat up the c@ts?? I had to test it so I removed the front bumper and removed the hose leading into the pump. I started the car and felt the pump`s suction. Its wasnt that big of a suck. . So I pulled it out of the car completely and tried blowing into it with my mouth..lol no jokes here, I reinstalled it and tried the engine start without the hose. Again the pump turns on and the suction is minimal. So Dont get discouraged if the pump isnt pumping enough air!!! You`ll find out later. So i checked the hose next that connects the air pump and the check valve. All good No cracks..I pulled off the check valve and it was caked inside with carbon dust or whatever inside it with brake cleaner and sh*tload of q-tips. Dried it well and reinstalled it. Pulled out the airline PIPE and checked the o-rings. Instead of relying on the o-rings for seal I added RTV high temp silicon. I applied it back of the o-rings. Not the tube part that goes insde the engine block I wanted the O-rings to do its job. Applying the RTV helped seal a wall if there was any leaks after the o-rings. SES light disappeared and no more secondary airpump issues

[dville]

No more check engine lights since hose was repaired.

[Pimo]

New guy here. Just wanted to say that I also swapped a air pump off an Audi and it is working well. I believe it was out of a 2.8 12 valve A6. I also had to replace the fuse under the passenger seat for the pump.

Working great and no engine light!

[jaugustavo]

So how necessary is this pump...really? If it pumps air past exhaust valves at start up to reduce start up emissions...

[Strahan]

Well, I don't know how California works but in Pennsylvania we need to get our cars inspected yearly. If the check engine light is on, it fails so even if the pump is pointless we have to fix it because it'll throw codes.

Plus it's just annoying to have to drive around with that light glaring at you lol. When mine went out, I just got a used one from eBay for $80. Been about a year now and it's still working fine.

[SFX Group]

I dont like pulling old post up, however....

my 750iL (10/1999) has been doing this pump thing for the past 8 months (only driven about 1000 miles) and the dealer is hoping this is what's causing a misfire (well the valve, however my pump is shot as well) (had all new injectors and gaskets as well as new sparks etc.., swapped distributor, cables and even control units over).

Now to my point, there is a company in USA who refurbish these pumps and will give you 2 years warranty if fitted by a dealer (link below), i have one, will let you know how it goes.

They are saying at least 1 valve (i have the V12) has seized open the other looks very suspect (100k miles), will keep you posted here on this. I supplied the dealer the part for the pump, they are supplying valves i think.

http://www.rebuiltairpump.com/

[TxDarth]

I noticed the Volvo pump coming soon. I had a '98 Volvo V70R wagon - I had two pumps fail on that car in 100K miles. Known problem because of the location. very low under the battery and the SAS valve would cause moisture to fill the pump. Cost as I recall as close to $400.00........

[franco90]

good Write up for you guys

[SFX Group]

UPDATE (on my same car about 2 years later after new pump)

Runs perfect.... turned out that:

Pump had failed, this was pulling way to much power from the battery, it also may have damaged my battery transfer switch (which i have to replace NOW), as my 750iL has 2 batteries i have a transfer switch between them that was failing when the pump failed and has now totally failed.

The valves had also seized up, 1 fully the other partial, they have both been replaced. With the V12 engine, both vents went to the right hand airbox (as from the drivers seat), this airbox feeds the left side engine, it was this side that was shutting down by it not being happy about combustion. Basics seems to be the valves failed, which then lets condensation built up in the pump creating water = destroy pump, left uncontrolled will miss fire the whole side of the engine that airbox feeds.

Might also have created a bad voltage transfer switch over pulling way to much power to handle.

I use 91 octane fuel, it was likely the previous owner(s) did not....

That supplier seems good as my pump still works, that said ive not pulled it out of storage yet this year. I would buy again from those guys.

[Sobek]

That's rather interesting actually, that it failed and pulled too much power. Tell me, did you notice that on your first start of the day, when the pump kicked on it dimmed your dash lights momentarily or made your revs drop? Mine does this, and it has got a bit noisier over the last year. It always feels to me like it's sucking down WAY too much power when it engages - sometimes it can bog my engine right down near stall revs on a cold morning...

I was thinking of just removing the cats, disconnecting and capping off the pump, and coding it off to just be done with it as we have no emissions systems here and it's one less maintenance item to worry about. Ideally just need some kind of way to remove the secondary air pipe and cap off the holes going into the exhaust banks, hmmm.

[SFX Group]

When i got the car the pump sounded like a Jet Engine (sounded kinda good when starting the car, people would ask whats under the hood), anyway, after about 2 months, i notice when i start the car, then got out, all the internal lights would dim hard, then the pump was running by the time i got to the front of the car.

I didnt put them together until the dealer had codes for the pump (which by then i worked out was the Jet Engine noise / dimming lights), also it turns out (as my battery transfer switch failed about october 2014 when i put the car away) he said he had seen these codes in the memory from when the pump was failing. I bet this was pulling way to much power to handle and put way to much stress on the battery transfer switch. No fuses had blown, but the lights dimming, that was major, the car didn't stumble at idle (it does now as the transfer switch is pulling power away from the whole car, they replicated the fualt by pulling the battery on and off while it was running, exact same fault shown).

As my 750iL has 2 batteries have a switch between them so the car can handle the power distribution, i am sure this failing after that pump pulling way to much power is connected.

I am not sure how i will get it to the dealer, the power is now that bad...


Buy a new pump (from the link i have above) and get the valves done, the whole job is complete once that pump is changed and the valve (or 2 if you have 2) are done (there all plug and play). My pump was full of water, they had a soaked arm when pulling the power connector of it. I was told the heat thrown back from the valves stuck open when the pump isnt running condenses in the pump, once the valves are closed then nothing back feeds.

I wouldnt want to do the job myself on the V12 engine for the valves, but i am sure others are ok.

That's rather interesting actually, that it failed and pulled too much power. Tell me, did you notice that on your first start of the day, when the pump kicked on it dimmed your dash lights momentarily or made your revs drop? Mine does this, and it has got a bit noisier over the last year. It always feels to me like it's sucking down WAY too much power when it engages - sometimes it can bog my engine right down near stall revs on a cold morning...

I was thinking of just removing the cats, disconnecting and capping off the pump, and coding it off to just be done with it as we have no emissions systems here and it's one less maintenance item to worry about. Ideally just need some kind of way to remove the secondary air pipe and cap off the holes going into the exhaust banks, hmmm.

[franco90]

Damn it I having problems Change the 107 fuse so what next I will replace the air pump

[Smoothbimer]

m5hoot, sorry to dissapoint, but my primary objective was to clear my dash of any warning lights.

I had just spent $300 on the ABS module rebuild and only the SAP check engine light remained.
So I did get lucky finding the perfect fitting pump, but I was prepared to search Volvos, and other European cars for ANY air pump at a low cost and do some creative plumbing.

I did NOT change the exhaust valve. I am aware the pump will fail again, but at $17 I can at least live with some peace, quiet, and no check engine light until this one fails.

At that time if I still have the car, I will probably get a NEW air pump unit from one of the links posted and replace the exhaust valves at that time...

I only took the bottom of the OE pump off, and it only had brown dust there as you can see in the pics. No evidence of moisture, but I did not dig into it any further.

Thanks for the feedback.

Just soak the valve with seafoam by disconnecting the air hose and pouring a couple ounces of seafoam in there, let it soak overnight and be prepared for some smoke the following day. Do this a few times and your valve will be clean. As long as the valve diaphragm is good, the valve will work like a charm. Great writeup!!!!

[dville]

Looking at this old thread.
These pumps are ALL over the junkyard on pretty much all European cars, most made by the same company Pierburg.
Many Golf, Jetta, Volvo, BMW, Audi have them and they are cheap at the yard.

make sure your hose from pump to valve does not have any cracks in it.