Secondary Air pump (SAP) troubleshooting and repair. (2000 BMW E39 528i)

[Kibokojoe]

Secondary Air pump (SAP) troubleshooting and repair. (2000 BMW E39 528i)
If you are receiving two OBD errors P1421 and P1423 it maybe your SAP system
I have read several of the online manuals and Bentleys is worthless, they all gave me a headache by the time I was finished. They all made it harder to determine the problem then they needed too. So to help the next guy (simply) through this problem here is my write up.
Take a look at the illustration there are four major components to the SAP system.
1.Secondary air pump (SAP
2.Air pump valve (APV)
3.Electric valve (EV)
4.Non-return valve (NRV)
First test detach hose from the SAP at the APV (# one with a yellow circle). Mine has the squeeze ring. Once detached have someone start the car. Car has to be cold for at least 4 hours. Feel for air is blowing from the SAP.
If blowing SAP is good
If no blowing SAP bad
If SAP is blowing feel the inlet side of the APV if you feel exhaust APV is bad. Test for one minute to see if valve eventually closes.
If APV is closed check the vacuum on the APV. I used a mitivac. Check APV by itself (it should hold a vacuum with no leaking). Then check the hose running from the APV to the manifold. I attached the mitivac at point A and put my finger over point B. This is where I found my leak… hose was rotten. Check the rest of the hose from C to the manifold.
The NRV is directional (Arrow). You can check it with the mitivac, I just sucked on it to determine the direction of the flow, it only goes one way. If you can draw air both directions the NRV is bad.
The biggest pain in this project was getting the EV out for inspection. The EV is under the back of the intake manifold and you have to use a small mirror and a flashlight to see and determine how to get the EV off of the mounting bracket.
Remove the right side air box
Remove the beauty covers from the top of the engine. Makes it easier to check the vacuum hoses and to get at the EV
While you’re doing this it is best if you replace all the hoses # 7 and #4.
If you look at the side picture of the EV you will see a clip. You have to pull the EV towards you while pushing in on the clip towards the engine. I used a thin blade 6” screwdriver. Unless you have someone to hold the mirror and light you will have to do this blind. Also the on-line illustration of the EV are backwards. (red arrow).
Anyway that’s it. Kibokojoe

[Ross]

Nice, concise diagnostic procedure. Since the wife has an E39 I'm sure I'll be needing it one day.
Thanks

[Bill R.]

After 2004 it got even better, no vacum lines on the valve at all. Just the pump and the valve.

[Kibokojoe]

I need to do a write-up on the Crankcase ventilation/oil separator (CCV) and the one I like to call the three hose repair. For this one you have to pull pretty much everything off the left side of the engine including the intake manifold. Why BMW decided to use plastic pipes on the engine block is beyond me. The plastic pipes break off at the engine block interface and you have to dig out the broken pieces…Lots of fun.

[shogun]

Thanks for that info, Joe. I had the same problem on my E36 M3 02/98. Rattling noise like a tin can when cold starting for about 1-2 minutes.
Checked the pump, o.k., then I found that the vacuum hoses between
2.Air pump valve (APV)
3.Electric valve (EV)
4.Non-return valve (NRV)

were brittle and leaked. Always got the code F6 with the Peake code reader.
Peake:

Table 19:

F5: "Secondary air system flow too low, Cyl # 1-3"
F6: "Secondary air system flow too low, Cyl # 4-6"

Replaced them with good silicone hoses and problem gone.

Here some more info:

MODEL E39 M5 and E52 Z8 with S62 engine produced up to 11/30/00.
SITUATION: A rattling noise coming from the front of the engine (VANOS area) may be heard for a few seconds after start up.
CAUSE: The VANOS adjusting units may cause a momentary rattling noise after the engine is started due to varying torque of the camshafts before sufficient VANOS adjustment oil pressure is built up. When the engine is switched off, oil bleeds out of the high-pressure chamber in the VANOS adjustment cylinder. This can cause the VANOS adjustment piston to move freely against the housing during engine start up causing the momentary rattling noise. This noise has no effect on engine power output or durability.
CORRECTION M5 and Z8 vehicles produced from 12/1/00 incorporate a VANOS accumulator shutoff valve which prevents oil bleed off of the high-pressure chamber after the engine is switched off.
On a customer complaint basis only, a VANOS accumulator shutoff valve can be installed to eliminate the momentary rattling noise after the engine is started on vehicles produced before 12/1/00.
http://www.bmwz8.us/pdf/Z8_VANOS_s62.pdf


BMW E36 Secondary Air Pump and Non-Return Valve Replacement

Vehicles:
1*** and up U.S. E36 323i/328i/M3.

Symptoms:
1. A Check Engine light that returns the fault codes F5 and F6. These codes indicate that the secondary air flow system is too low for cylinders 1-3 and 4-6, respectively.

2. Before the Check Engine light comes on, you will likely notice a whining, scraping, screeching, whistling or groaning sound coming from the passenger side of the engine compartment. The noise begins immediately after a cold start and stops after a minute or two.
Problem:
The secondary air pump has failed due to moisture inside the pump.

Solution:
Replace both the secondary air pump and non-return valve.

Background on the Secondary Air Pump
The secondary air pump, located near the firewall on the passenger side of the engine compartment, draws air from the engine compartment and injects it into the exhaust manifolds to provide extra oxygen to the catalytic converter and reduce cold start emissions. A non-return valve mounted on the exhaust manifolds normally prevents exhaust gases from flowing back into the pump. When the non-return valve fails, moisture in the exhaust gases accumulates in the pump, causing it to eventually fail.

This pump normally sounds like a vacuum cleaner under the hood, and it only operates for the first couple of minutes after you start the car. It will not leave you stranded if it should fail. You can replace the parts at your leisure, unless you have an emissions inspection coming up.


The F5 & F6 codes are indicating that the secondary air injection system is not functioning properly. This system injects (pumps) air into the exhaust manifolds during a cold start. This is intended to supply additional oxygen to promote a more complete burn of the outgoing exhaust gasses, during the initial cold start and warm-up phase. Failures of this system are quite common. The typical failure is that the check valve that is mounted on the exhaust manifold fails in the open position. This allows exhaust gasses to run back up to the pump, when the pump is not running. This eventually destroys the pump. Therefore, you typically have to replace both the check valve and the pump. The remainder of the system is comprised of the pump to valve hose, vacuum hoses, an electrical vacuum control switch and a fuse and relay. There is the possibility that any of these other areas that control the pump and the check valve could have faults as well.


for my 02/1998 E36 M3 the relay secondary air pump is

K6304 X6304 SECONDARY AIR PUMP RELAY
on the right of the fuel pump relay which is K6301w X6301

see page 19 of 386
http://www.bmwtechinfo.com/etm/data/e36/e36_98.pdf

Air Pump Relay (K6304): schema is 85-86 and 30-87a-87, PN 12631742690
Relay 5-Prong Salmon Red for Air Pump E36 96-99 All
5-Prong salmon red changer relay for air injection system.
Application
E36 96-99 318/323/328/M3
E38 96-01 740/750
E39 96-03 528I/540I
Z3 96-02 All
E46 99-05 323/325/328/330/M3

BMW Part Number: 12631742690

The pumps is repairable
BMW SMOG PUMP REPAIR - YouTube

drill the rivets out and replace them with screws with bolts, 4mm and 40 mm long.

and that is apparently exactly what this company is doing, which sells reman pumps, they replace the bearing too.

rebuiltairpump dot com

Quote:
Product Description:BMW E36 rebuilt secondary air pump. The pumps is disassembled, new main bearing is installed, armature is polished and the rest of the parts are cleaned, inspected and replaced as needed. Pump is then bench tested for 10 minutes. two year replacement warranty comes with your purchase. Your old pump is required as a core, we provide a free fedex return label, so once you or your mechanic has installed the new pump, you can return the old one to me at no additional cost. We highly recomend replacement of the check valve, if your pump has any signs of water in it or brown residue, you will need a check valve. A failing check valve is the most common cause of air pump failure

I have not bought the part from this company, but the price of $139 is not bad, unless one tries to repair DIY, what I will try
How To Test A BMW Smog Pump Air Injection Check Valve

YouTube
How To Test A BMW Smog Pump Air Injection Check Valve - YouTube

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:

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.

[michaelanthony]

Does anyone have a diagram for the SAP/value/hoses for a 2004 525i

[shogun]

check here
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