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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #26  
Old 05-07-2011, 08:46 PM
cn90 cn90 is offline
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Quote:
Originally Posted by MaximeM View Post
...
3- Since my air pump was still not working, I had a look at the relay and measured voltage and resistance. Here are my findings:

- 87 was hot (12v) all the time
- 30 is not hot.
- 85 only had .1v with the key in position II
- resistance b/w 85-86 was 78 ohms (not sure if this is important).
Max,

Wait for "billj3cub" to get back on this issue.

I find it hard to believe billj3cub's car wired backward, if so, it would have given problem the last 10 years or so.

Make sure you remove the SAS Relay and look at the pins and make a diagram on a piece of paper so you know exactly the locations of 30, 85, 86, 87 etc. on the CONNECTOR.

Then search the internet for the wiring diagram for your model year. What is your model/year?

Wiring Info is here:

http://spaghetticoder.org/bmw/wds/

http://www.bmw-planet.com/diagrams/release/en/
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  #27  
Old 05-07-2011, 09:11 PM
MaximeM MaximeM is offline
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Quote:
Originally Posted by billj3cub View Post
Your #86 terminal on the connector should be hot (12v) when you turn the key on. If not, then you need to check the F31 fuse (where is that located?).

You can test the air pump by putting a jumper wire between 87 and 30 to see if the pump runs.

You have the same 87-hot (from fuse 107) and 30-cold (to pump) apparent backwards connector wiring that I believe I have on this '01 525i. My customer has the car right now. Give me a week and I will get the car back to install a good pump I got at a wreaking yard for $125 (his original pump was all melted down inside and not rebuild-able). I will triple check everything, swap the wires so #30 in the connector is hot and #87 in the connector runs to the pump then report back on how it all turned out.

***
Sounds good.

Looking forward to your reply.

Many thanks.

Max
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  #28  
Old 05-08-2011, 07:27 AM
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540iman 540iman is offline
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Ok, I pulled my Bentley out as it has been a while since my SAP went south. Mine filled with condensation, froze in the winter causing the rotor to be "locked". The caused excessive current drain on fuse 107 blowing it. So, I replaced fuse 107, the relay (salmon colored), pump, hoses, and valve. The whole she-bang.

First, contact 87 should ONLY be hot for about 90 seconds after turning the key on AND STARTING CAR. If you waited with car running and 87 stayed hot, then your relay is toast as it is stuck closed. This would cook your pump as they are only made to run a MAX. of about 4 minutes before they will burn up. You need to make sure when you test for 12 VDC at 87 that you started the car and kept your meter on relay contact 87 for at least a few minutes. At least you know fuse 107 is good. If contact 87 is hot verify you have 12 VDC at the pump as well. You really need to just pull the pump out and using a car battery put a known BIG 12 volts to the pump and see if it hums and or turns. If it does not even hum, it is toast. If it hums, but acts like it is locked, drill out rivets and take apart and see if you can clean it up and un-freeze it. Look for an Audi Pierburg pump and save about $200 bucks over a BMW pump. Audi pump is just as good. Search for the post about replacing BMW pump with Audi pump. Direct fit except connector pigtail from your BMW must be changed to mate with the Audi pump. No big deal. You can even just use stake-on pins. Just observe polarity.

Pins 85 & 86 are the relay coil
Pin 30 is constant 12VDC from fuse 107
pin 87 goes hot when DME calls for pump to run
pin 87a is irrelevent for our purposes.

Last edited by 540iman; 05-08-2011 at 07:31 AM.
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  #29  
Old 05-08-2011, 08:18 AM
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bluebee bluebee is offline
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http://bimmerboard.com/forums/posts/792253

Quote:
Originally Posted by 540iman View Post
it has been a while since my SAP went south.
I went to the VERY best of E39 Links to see if this DIY is listed and realized we didn't have a concise paragraph about the SAP, SAS, and fuse #107.

Here's what /secondary(F3) nets us, from top to bottom:
Doing just /SAS(F3) nets these additional best links:
Next, I'll open them all up, read 'em, cull out duplicates, and put them into a keyword-rich coherent sentence.

- Where is the secondary air pump (1) & how to diagnose a secondary air system failure (1) & what are the most common two failure modes (1) & a DIY to perform SAS troubleshooting with the infamous fuse #107 (1) (2) & what to do when the SAP (1) clogs or freezes (1) or the diverter valve clogs (1), taking out the S.A.S. (1) (2) (3) (4) (5) (6) (7) & a S.A.P. replacement DIY (1) & a Pierburg air pump maintenance (1) & rebuild DIY (1) (2) & well thought out SAS/SAP simulation testing (1) & repair strategies (1).

Last edited by bluebee; 05-08-2011 at 09:37 AM. Reason: Had to read all the threads and put it into a coherent sentence. Also added Bill's comments below as best I could.
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  #30  
Old 05-08-2011, 08:58 AM
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540iman 540iman is offline
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SAP failure-Too long as usual :-(

Hi BLUE!

You know the post is valuable when you volunteer to pull it all together! Not to hijack someone's thread, but possibly the most important two pieces that I would want to make sure get included are the following: There is a post out there involving a guy who found a substitute pump for the BMW Pierburg. It is a Pierburg from an Audi and he found a working unit in a junk yard for $17! Then, another poster found that this Audi Pierburg can be had NEW on Amazon for about $100. It is a direct fit except for the connector and this may be the biggest help I have ever seen. The Audi pump puts out as much air as ours and is 1/3 the cost!

The second piece I believe is important is that there is no SIM to be built easily to fool the car and work around the whole stupid system that adds nothing except passing US emissions which BMW could not pass during initial cold starts only. After about a minute, the BMW emmissions were acceptable, but all this crap had to be added to "dilute" the emmissions for just 60 seconds at a cost of about $600 if you replace everything. So, what happens if you do replace everything with new BMW parts and you still have the error which will also set the SES light on the dash? The PowerChips people sell a chip designed to improve performance and whether you buy into the concept and value of the power chip for this purpose or not, they offer -as an option on your customized chip-the software that will replicate a European car that also has the SAP, but when it fails will not set the SES light or cause any issue whatsoever. You need to ask for this if you buy a PowerChip. It will just set a code that can be read, but will not cause you any issues. The Power Chip software widens the parameters the DME will accept as sufficient dilution of the exhaust to not set a SES. The DME looks for the correct signals from the O2 sensors telling the DME that the pump must be running as the O2s are swinging lean far enough. Well, what happens if your heads have excessive carbon build-up which we know plaques a lot of M5s as well as other E39s? This is what happened to me. I took my car to the Stealer as I had replaced everything including the valve and I knew the system was operating properly, but the SES light would not stay extinguished. The BMW techs confirmed that on my car, not enough fresh air from the pump was making it to the exhaust system due to carbon blockage in the heads. Cost to fix? $8000. It is a big job and there is an extensive post by a BMW mechanic of doing the gun drilling of the heads to clear the carbon. Next best solution is call the PowerChip folks and negotiate for just the Euro SAP software which took care of my SES light and allowed me to pass emmissions.

Bill

P.S. Blue, if you have not read the post from the M5 board on the BMW repair of a head to remove carbon build-up, you should search for it and read it. You might want to include it as well as it details the path the air must travel to get to the exhaust. #1 failure mode for SAP is condensation due to heat from the exhaust traveling by a faulty valve and hitting the cold pump. This can ONLY happen if the valve stays open due to crap being in there (soot, carbon, rust) keeping it open while the pump is not running allowing hot gases to hit cold pump. Second failure mode is relay contacts sticking closed as pump is over-driven to the point where it can only run for about 4 minutes at a time or it wil burn up.
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  #31  
Old 05-08-2011, 09:33 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by 540iman View Post
a guy ... found a substitute pump for the BMW Pierburg ... there is no SIM to be built easily to fool the car and work around the whole stupid system
DISCLAIMER: I'm severely hampered doing SAS/SAP research because I, myself, have never dealt with the system and I really don't understand it at all.

I was culling while you posted this so take a look at the edits above.

Those links don't have the substitute Pierburg yet but they do have CN90's discussion that his pump was similar to that on the Audio, Mercedes Benz, Volvo, VW, etc.
- DIY: 1998 528i S.A.S Pierburg Air Pump Maintenance and Rebuild Info

As for the 'simulator' ... how does this thread look?
- Air Pump Simulator for 2 Bank all 6 Cylinders



Quote:
Originally Posted by 540iman View Post
there is an extensive post by a BMW mechanic of doing the gun drilling of the heads to clear the carbon. Next best solution is call the PowerChip folks and negotiate for just the Euro SAP software which took care of my SES light and allowed me to pass emissions ... read the post from the M5 board on the BMW repair of a head to remove carbon build-up
Gotta run right now ... but will 'try' to find those later ...

Quote:
Originally Posted by 540iman View Post
#1 failure mode for SAP is condensation due to heat from the exhaust traveling by a faulty valve and hitting the cold pump. This can ONLY happen if the valve stays open due to crap being in there (soot, carbon, rust) keeping it open while the pump is not running allowing hot gases to hit cold pump.

Second failure mode is relay contacts sticking closed as pump is over-driven to the point where it can only run for about 4 minutes at a time or it wil burn up.
Seems to me I should just link to your post above and title it "common failure modes".

EDIT: OK. So I did add your post so that others beneift. The 'coherent keyword-rich sentence' is more keyword rich than coherent, but, for better or worse, here is what it currently is (it will improve over time as my understanding of the SAS develops slowly).

- Where is the secondary air pump (1) & how to diagnose a secondary air system failure (1) & what are the most common two failure modes (1) & a DIY to perform SAS troubleshooting with the infamous fuse #107 (1) (2) & what to do when the SAP (1) clogs or freezes (1) or the diverter valve clogs (1), taking out the S.A.S. (1) (2) (3) (4) (5) (6) (7) & a S.A.P. replacement DIY (1) & a Pierburg air pump maintenance (1) & rebuild DIY (1) (2) & well thought out SAS/SAP simulation testing (1) & repair strategies (1).
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Last edited by bluebee; 05-08-2011 at 09:38 AM.
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  #32  
Old 05-12-2011, 03:48 PM
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540iman 540iman is offline
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I need to learn to quantify my posts better! I should have said that no working SIMS have been made (to the best of my knowledge) for a 540. There have been some advertised for the I6s for a while, but not for the 540 AFAIK. I do not know whether the 540 is more complex or if the 540s DME looks for the appropriate current draw of the pump motor, but I believe it fair to say that a board made with the components shown here would not nearly satisfy the 540s DME. I would be very curious for the builder to talk me through what this uhm...circuit is actually doing. I can only assume that it uses the trigger that turns the pump on to flip the relays which somehow lower the voltage that the O2s report back when the SAP is supposed to be on. We know a properly functioning O2 sensor fluctuates fairly rapidly between about .1V and .9V with .5V being in theory an air-fuel ratio of about 14.7 to 1. When the car is lean, the voltage drops below .5V and when the car is rich, the voltage rises above .5V. The resistors need to be such that the O2 voltage still "swings", but is lower as if the pump is running and diluting the exhaust to be less rich. I have my doubts about this simple board working on a 540.
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  #33  
Old 07-12-2011, 12:01 AM
billj3cub billj3cub is offline
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I finally got the car back from the customer, installed the good air pump from a wreaking yard out of another 525i (cost: $125, talked him down from $150), installed a new air valve on the exhaust and a new electric valve under the intake manifold (remove the cabin air intake assembly to make this job much easier: remove squeeze clip at front edge of air box, remove lid and filter, un-clip snorkel swing away and remove, lift out air box,) and checked the wiring. Here are my results:

The physical layout, or pin-out, of the Secondary Air Pump Relay and its connector with all the numbered positions that cn90 shows are the same as in his most excellent post. HOWEVER, the PRINTED WIRING DIAGRAM for the Secondary Air Pump Relay does not agree with how this car is wired, nor does it agree with how the Secondary Air Pump Relay functions and, most convincingly, does not agree with the wiring schematic that is MOLDED INTO THE SIDE of the Secondary Air Pump Relay. The 30 and 87 are reversed from the Printed Wiring Diagram with the pump connection being #30 and the fuse F107 (hot all the time) being terminal #87. There is no mistaking this. I did not get it wrong.

Look at the side of the Secondary Air Pump Relay and take note of the wiring diagram molded into the side of the relay confirming the layout of the switching portion of the relay and how it differs from the printed wiring diagram. #30 (going to the pump) is the switch while #87 (the f107 fuse) and #87a (the ground) are the two contacts that #30 switches between. This makes perfect electrical sense as well.

Most troubling is the part number that cn90 lists for the Salmon colored Secondary Air Pump Relay is the same number that is molded into the side of this car's relay: 12.631742 690. Also molded on the relay is: TYCO V23134-E53-X344. On the top, printed in black letters is: ++0109

This 525i has a build date of 3-01.

The pin-out for the Salmon colored Secondary Air Pump Relay (verify by actually looking at the diagram on the side of your relay):
30 - Pump
87 - Fuse f107, hot all the time, located under the carpet in front of the passenger seat.
87a - Ground located at right front side of the engine compartment.
86 - fuse f31 located in the drop down fuse panel in the glove box.
85 - DME Control Unit pulls this pin low which energizes the coil in the Secondary Air Pump Relay, switching pin 30 (pump) from 87a (ground) to 87 (f107, 12 volts) which powers the pump.

By the way, I am going to replace the Secondary Air Pump Relay in this car simply because the motor in the bad air pump I took out was completely melted. The obvious scenario that could cause this is a stuck relay that would allow the pump to run continuously to destruction. It is probably a good idea to replace it when you replace any pump because it is cheap ($10?) and operates under a significant load (13 amps).

~~~~~~~~~~~~~__/)_~~~~~~~~~~~~~~
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  #34  
Old 07-12-2011, 06:38 AM
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540iman 540iman is offline
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It has been a while since I did my SAS re-build, but I believe you have it wrong just from looking at the relay stampings and from memory, at least on my 540i. I did not have the Bently then so I had nothing to compare to, but believe you are incorrect. 30 was power in from fuse 107 and 87 was N/O contact leading to pump. This is all from memory. You can see by looking under the relay at the relay holder...the large red wire is the constant power from fuse 107 and the other heavy gauge wire leading to the pump is on 87.

Last edited by 540iman; 07-12-2011 at 06:51 AM.
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  #35  
Old 07-12-2011, 10:26 AM
cn90 cn90 is offline
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Quote:
Originally Posted by billj3cub View Post
...The physical layout, or pin-out, of the Secondary Air Pump Relay and its connector with all the numbered positions that cn90 shows are the same as in his most excellent post. HOWEVER, the PRINTED WIRING DIAGRAM for the Secondary Air Pump Relay does not agree with how this car is wired, nor does it agree with how the Secondary Air Pump Relay functions and, most convincingly, does not agree with the wiring schematic that is MOLDED INTO THE SIDE of the Secondary Air Pump Relay. The 30 and 87 are reversed from the Printed Wiring Diagram with the pump connection being #30 and the fuse F107 (hot all the time) being terminal #87. There is no mistaking this. I did not get it wrong...
Hi billj3cub,

Thanks for the follow-up on the 2001 525i wiring.

I just verified the Electrical Wiring of the 2001 525i and the "Published Data" is exactly as in the diagram I posted on the 1st thread.
In other words, the "Published Diagram" is the same for 1998-2003.
The flow is from battery ---> #30 ---> #87 ---> Air Pump.

In your case, your trouble-shooting procedure showed that:
The flow is from battery ---> #87 ---> #30 ---> Air Pump.

From an electrical standpoint, it does not matter because current still flows to the Air Pump.

I find it interesting that BMW changed their wiring in this manner, while it works fine, it makes no sense to switch the wiring pathways. Maybe they had too many bradwurst and German beers while working on the 2001 525i LOL!

Last edited by cn90; 07-12-2011 at 10:56 AM.
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  #36  
Old 07-12-2011, 10:51 AM
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540iman 540iman is offline
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I bet that if he looks at the base of the relay socket, he will find a red wire on relay pin#30 and I think a heavy gauge brown wire on relay pin 87. You are of course correct CN90 that as long as you are checking during the first 90 seconds after a cold start everything is common. After that, he should find that only pin #30 stays hot coming from fuse 107 and pin 87 will drop to nothing unless the relay is bad and is staying in the N/O position full time..
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  #37  
Old 07-12-2011, 10:55 AM
cn90 cn90 is offline
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I also want to add the following comment for people reading this thread on how to check relay operation, there is a BIG difference between checking relay when it is attached to the car and when it is removed entirely from the car.

- With relay in the car, lift it gently up a bit so all the legs are exposed (about 2mm or so), so the voltmeter probes can reach the relay's legs for testing.

- With relay out of the car, one can only check for continuity or open circuit, unless one applies voltage to the appropriate pins.
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  #38  
Old 07-12-2011, 12:02 PM
billj3cub billj3cub is offline
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I believe it is safe to assume that 540iman and cn90 are correct in their descriptions of the wiring scheme in their cars while at the same time I have no doubt that the pin-out and function I described on the 3-01 525i that I just worked on is correct as well. So, I can only surmise that the discrepancy between these cars must lie in different Salmon colored Secondary Air Pump Relays. If my relay was installed in your car then the 30 terminal (you say is fuse f107) would switch between 87 (to your pump) and 87a (ground) which would blow the f107 fuse.
cn90 listed the Secondary Air Pump Relay part number in his original post from a parts list, presumably not from actual inspection of his relay. Could you, 540iman and cn90 and anybody else reading this, please inspect your relay and report back on four observations?:
1) What are the numbers molded into, and/or printed on your Salmon colored Secondary Air Pump Relay?
2) What is the switching scheme in the diagram molded into the side of your Relay? Mine shows 30 as the switch with 87 and 87a as the two terminals that 30 switches between. It is this diagram on my Relay that is in direct contradiction to the Printed Wiring Diagram that cn90 posted where 87 (it shows pump) switches between 30 (it shows fuse f107) and 87a (ground). This is the main item that I would like to have verified.
3) Does 30, 87, 87a, 85, and 86 molded into the underside of the relay right next to each terminal match up to the pin layout in the connector as shown in cn90's original post? Particularly, verify if there is a 87a and not just two 87's (or something else) next to each other.
4) Does 87a in the connector show continuity to ground?
The upshot of all this is that posters like MaximeM and I would get confused (I certainly did) following cn90's post. Also, most importantly, if you replaced your relay with part number: 12.631742 690 (which is the number on my relay) as listed in cn90's original post, and put it in your car it would blow the f107 fuse the moment you plugged it in (unless the 87a terminal in the connector does not go to ground like the printed diagram says). That would be bad. That is why I am taking the time to resolve this so there is not a Forum Post Bomb waiting to blow up the f107 fuse on some non-electrical noob.
By the way, I did verify the function of my relay by driving the 85 and 86 pins with a 5 volt signal and found that pin 30 switched from 87a to 87. Our '02 M3 has the same SAS system so when we get it back from the painters I will verify the M3 wiring, relay and function as well.
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  #39  
Old 07-12-2011, 12:18 PM
cn90 cn90 is offline
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Great,

Why don't we each post our relay pinout pictures?
I will post my relay pics soon.

If anyone posts relay pictures, please indicate:
- Year, Model
- Relay PN Number
- And of course a close-up pic showing the printed diagram!
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  #40  
Old 07-12-2011, 12:22 PM
cn90 cn90 is offline
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billj3cub,

In your previous post #33 above, you keep referring the testing the Relay pins but just out of curiosity, how did you test your relay: connected or disconnected?

Also did you test the Connector itself.

Of course, as you know, there is a BIG difference between testing the RELAY and testing the CONNECTOR!
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  #41  
Old 07-13-2011, 10:25 AM
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540iman 540iman is offline
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I think we may all be saying the same thing....I am not sure where CN90 has shown a schematic that indicates anything but 30 receiving the power from fuse #107? I also remember being confused now that you mention it that the schematic certainly does show the hot battery power going through fuse 107 to ground and IIRC when I tested pin 87a, it was not going to ground. It can't as you pointed out as the fuse would then blow as soon as the power is switched away from the pump. However, you also are agreeing that power comes from 30 and is switched between 87 and 87a. I want to say that I talked to BMW about the schematic and was told that when power is switched away from the pump, it goes back to the DME and NOT grnd! I hate when bad information is shared by the forum as I would rather not post then give advice or opinion that is not correct. My 540 is in Indiana now with the wife or I would go ahead and pull the cabin air box and the DME lid and verify it for all. I am working from memory now, but now that you refresh my memory 87a did not show continuity to ground directly. There was resistance there as though you were checking the inputs to a transformer winding. I believe it was about 1000 ohms to ground. This is a valid spotting by you that the schematic is partially wrong.

Last edited by 540iman; 07-13-2011 at 10:27 AM.
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  #42  
Old 07-13-2011, 10:38 AM
cn90 cn90 is offline
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I think what billj3cub says is there is discrepancy between "Published Diagram" and what he found in his customer car.

"Published Diagram"
#30, F107: hot all the time, #87 is "switched".

What billj3cub found in his customer car is the opposite:
#87: hot all the time, #30 is "switched".

From an electrical stand point, it does not matter, the SAS pump is still activated anyway, the only difference is how it is switched.
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  #43  
Old 07-13-2011, 10:54 AM
cn90 cn90 is offline
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Quote:
Originally Posted by billj3cub View Post
..If my relay was installed in your car then the 30 terminal (you say is fuse f107) would switch between 87 (to your pump) and 87a (ground) which would blow the f107 fuse.
This is interesting because in this particular setup, the SAS Relay schematic is designed in such a way that 87 and 87a are always in continuity, i.e., actually the same circuit. So your customer car relay is different than the earlier models from 1997-1998?

a. SAS Pump OFF:
#30 just opens, not connected to anything.

b. SAS Pump ON (when 85-86 is activated, it pulls a magnet and the relay's arm, which pivots on #1, swings from #2 ---> #3 in the pic below):
#30 ---> 87a ---> 87 ---> SAS Pump.







PS: For a primer course on Bosch relay, i.e., how it works and different configurations etc., people may want to look into this schema for headlight by Bosch relay (switching between 87 and 87a for low-beam and high-beam, which is very different from the SAS Pump):

http://www.bcae1.com/relays.htm




---
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  #44  
Old 07-13-2011, 11:25 AM
cn90 cn90 is offline
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I just looked up Relay K6304 schematic and maybe billj3cub has a point.

The "Published Diagram" is kind of different from what is molded to the side of the Relay.
The truth is to test the relay itself to find out EXACTLY how the relay works.
My theory: perhaps the relay's printed circuit is wrong (hard to believe but just a theory).

Anyway, I will take a look at my car tonight and verify.


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  #45  
Old 07-13-2011, 12:46 PM
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540iman 540iman is offline
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Quote:
Originally Posted by billj3cub View Post
2) What is the switching scheme in the diagram molded into the side of your Relay? Mine shows 30 as the switch with 87 and 87a as the two terminals that 30 switches between. It is this diagram on my Relay that is in direct contradiction to the Printed Wiring Diagram that cn90 posted where 87 (it shows pump) switches between 30 (it shows fuse f107) and 87a (ground). This is the main item that I would like to have verified.
:
Well, that is what I thought as well, but billj3cub seems to be saying here that #30 is the relay input which switches between 87 and 87a which agrees with your schematic. no??

He is 100% right though that 87a can't be going direct to ground or it would take out 107 right away. And, 87 and 87a can not be common or the pump would not shut off regardless? Intersting that we have "danced" around this whole deal and it can't be a mystery. If I had my car here I couold put an end to this real quick-at least for the 540. I am guessing that his cuastomers car is not available either as the socket generally has these numbers on it as well and all he needs to do is see which terminal has the heavy gauge red wire going to it and then verify the pump output lead

I am not sure he is reading your schematic correctly as your diagram clearly shows 30 as "center leg" of the relay and switches between 87 and 87a. CN90's schmatic shows exactly what you are saying your customers car is in reality. Will somebody make it clear to me what he said here in #2 DISAGREES with the schematic you posted....That is all I want to see. How is his statement above different than your schematic??

Last edited by 540iman; 07-13-2011 at 12:51 PM.
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  #46  
Old 07-13-2011, 12:51 PM
cn90 cn90 is offline
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This weekend, if I have time, I will go over the whole thing (testing the CONNECTOR, testing the RELAY) to get the whole TRUTH.
Perhaps the printed circuit on the relay is inaccurate and that is the only problem?
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  #47  
Old 07-13-2011, 01:02 PM
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540iman 540iman is offline
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This is so simple, I can't understand this whole thread! Your diagram (schematic) shows the following: 85 and 86 are the coil wires for the relay. When the DME says to run the pump, it sends power to the relay coil which is 85/86. When the coil is energized, the power on #30 which is always hot because it is fed by fuse 107, is directed to terminal 87 which is the pump. When the coil is not energized (after 90 seconds approx.) the power leaves the 87 terminal and goes to 87a. Where the schematic is wrong is that it shows 87a as going to ground which it can't possibly be.

In his statement #2 is exactly what your schematic shows, so where is the discrepency?

Last edited by 540iman; 07-13-2011 at 01:03 PM.
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  #48  
Old 07-13-2011, 01:44 PM
cn90 cn90 is offline
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540iman,

I kind of understand what billj3cub said: the discrepancy between what is "Published Diagram" vs "Relay Diagram".

"Published Diagram": The swivel point is 87a.

"Relay Diagram": The swivel point is 30.

See pic:


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  #49  
Old 07-13-2011, 02:18 PM
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540iman 540iman is offline
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Thumbs down

All agree with each other electrically when energized, but picture on relay is wrong. Good catch Billj3cub! My head was spinning there for a while and I thought CN90's last schematic was different from his first one, but now see that is not the case. The picture on the relay is wrong unless nothing was connected to pin 87a. The scematic shows 87a going to ground which mandates that 87 must be the center of the contacts and not 30 as the relay picture shows.

Last edited by 540iman; 07-13-2011 at 02:28 PM.
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  #50  
Old 07-13-2011, 04:45 PM
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540iman 540iman is offline
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Quote:
Originally Posted by billj3cub View Post
I finally got the car back from the customer, installed the good air pump from a wreaking yard out of another 525i (cost: $125, talked him down from $150), installed a new air valve on the exhaust and a new electric valve under the intake manifold (remove the cabin air intake assembly to make this job much easier: remove squeeze clip at front edge of air box, remove lid and filter, un-clip snorkel swing away and remove, lift out air box,) and checked the wiring. Here are my results:

The physical layout, or pin-out, of the Secondary Air Pump Relay and its connector with all the numbered positions that cn90 shows are the same as in his most excellent post. HOWEVER, the PRINTED WIRING DIAGRAM for the Secondary Air Pump Relay does not agree with how this car is wired, nor does it agree with how the Secondary Air Pump Relay functions and, most convincingly, does not agree with the wiring schematic that is MOLDED INTO THE SIDE of the Secondary Air Pump Relay. The 30 and 87 are reversed from the Printed Wiring Diagram with the pump connection being #30 and the fuse F107 (hot all the time) being terminal #87. There is no mistaking this. I did not get it wrong.

Look at the side of the Secondary Air Pump Relay and take note of the wiring diagram molded into the side of the relay confirming the layout of the switching portion of the relay and how it differs from the printed wiring diagram. #30 (going to the pump) is the switch while #87 (the f107 fuse) and #87a (the ground) are the two contacts that #30 switches between. This makes perfect electrical sense as well.
Ok...it really helps to re-read what others are trying to say! Here is how things should be and differ from what you say above: The diagram on the relay is wrong to the way the BMW is wired. 87 should NOT be hot all the time. If it is, you have the reason your customer's car needs a new SAS. If this pump runs more than about 4 minutes, it will fry itself. Pin 30 is not tied to the pump, but is as we have beaten to death...tied to fuse 107. Terminal 30 S/B hot all the time. Term 87 is the pump. Term. 87a goes to grnd. Terminal 87 is the terminal that toggles between 30 when the pump is running or 87a which is ground which simply means that both legs of the pump are grounded. If no wire at all was connected to pin 87a, the circuit would still function fine. Putting both legs of the pump to ground is redundant, but that's what the German engineers wanted for some reason. Your reading between 85 and 86 is just the resistance of the relay coil.
I think you need to check your customer's car again. Big red wire is on term #30 and is the only pin that will be hot all the time.

Last edited by 540iman; 07-13-2011 at 04:48 PM.
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