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Secondary Air Components Replacement
 
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Pelican Technical Article:

Secondary Air Components Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$250

Talent:

***

Tools:

Set of sockets 10mm, flathead screwdriver, plastic gasket scraper, hose clamp pliers

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Secondary air pump, air valve and gasket, hose clamps

Hot Tip:

Replace any cracked or dry rotted hoses

Performance Gain:

Working secondary air

Complementary Modification:

Replace engine air filter

The secondary air system is used to improve catalytic converter efficiency and reduce the emission of harmful combustion byproducts in the automotive exhaust. For a short period after a cold start, the catalytic converter is not hot enough to efficiently combine unburned fuel with available oxygen. An electric air pump forces fresh air into the exhaust stream just before the exhaust enters the catalyst. This extra air supplies the catalyst with additional oxygen, thus speeding up the combustion of unburned pollutants and raising catalyst temperature rapidly. When the catalyst reaches what is called "light-off temperature" (approximately 400-600 degrees F or 215-315 degrees C) it is capable of self-maintaining a high temperature and the high efficiency of combustion. At that point the secondary air system may be shut off.

A check valve is usually installed in the secondary air pump duct in order to prevent back flow of hot exhaust gases into the air pump.

The secondary air system is prone to faults that illuminate the check engine light. If you have fault codes for your secondary air, check the operation of the pump. You can test the function of the secondary air components using a BMW scan tool. If you do not have access to one, you can check secondary air pump function when starting the engine. When a cold engine is started, the secondary air pump will run for a calculated amount of time. For more information on how to test the secondary air system, see our tech article on secondary air system testing.  The check valve is the most common part to fail. In this tech article I will show you how to replace the secondary air pump and secondary air valve on 4-cylinder and 6-cylinder engines.  

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out body or interior items.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Models with 4-cylinder engine - Secondary air pump - Using a flathead screwdriver, loosen the secondary air pump inlet hose clamp.
Figure 1

Models with 4-cylinder engine - Secondary air pump - Using a flathead screwdriver, loosen the secondary air pump inlet hose clamp. (green arrow)

Models with 4-cylinder engine - Secondary air pump -Then remove the secondary air inlet hose from the air filter housing by pulling it straight off.
Figure 2

Models with 4-cylinder engine - Secondary air pump -Then remove the secondary air inlet hose from the air filter housing by pulling it straight off. (green arrow) Then pull it off the air pump and store in a safe place.

Models with 4-cylinder engine - Secondary air pump -Next, you will unclip the three air filter housing retaining clips.
Figure 3

Models with 4-cylinder engine - Secondary air pump -Next, you will unclip the three air filter housing retaining clips. (green arrows). One of the clips was hidden beneath the secondary air inlet hose. You will have to reach in behind air filter housing to access it.

Models with 4-cylinder engine - Secondary air pump -Disconnect the intake air sensor electrical connector by pressing the wire release tab and pulling the connector straight off.
Figure 4

Models with 4-cylinder engine - Secondary air pump -Disconnect the intake air sensor electrical connector by pressing the wire release tab and pulling the connector straight off.

Models with 4-cylinder engine - Secondary air pump -Working at the air flow meter, twist electrical connector counterclockwise to disconnect.
Figure 5

Models with 4-cylinder engine - Secondary air pump -Working at the air flow meter, twist electrical connector counterclockwise to disconnect. (green arrow). Then loosen the air flow meter hose clamp (yellow arrow). Once loose, remove the air filter housing from the engine compartment.

Models with 4-cylinder engine - Secondary air pump -Then, loosen the secondary throttle body hose clamp at the rear air boot (green arrow).
Figure 6

Models with 4-cylinder engine - Secondary air pump -Then, loosen the secondary throttle body hose clamp at the rear air boot (green arrow).

Models with 4-cylinder engine - Secondary air pump -Once loose, pull the intermediate throttle out of the boot.
Figure 7

Models with 4-cylinder engine - Secondary air pump -Once loose, pull the intermediate throttle out of the boot. You can leave the cables connected, just lay it aside.

Models with 4-cylinder engine - Secondary air pump -Next you have to disconnect the secondary air pipe from the pump.
Figure 8

Models with 4-cylinder engine - Secondary air pump -Next you have to disconnect the secondary air pipe from the pump. Squeeze the release tabs, and then pull the pipe straight off the secondary air valve to remove.

Models with 4-cylinder engine - Secondary air pump -Now it is time to unbolt the secondary air pump.
Figure 9

Models with 4-cylinder engine - Secondary air pump -Now it is time to unbolt the secondary air pump. You will have to lift it up to disconnect the electrical at the bottom. Start by removing the two 13mm nuts (green arrows) that secure the pump to the support bracket.

Models with 4-cylinder engine - Secondary air pump -Then working at the back side of the pump bracket, remove the wiring harness from the mounting clip.
Figure 10

Models with 4-cylinder engine - Secondary air pump -Then working at the back side of the pump bracket, remove the wiring harness from the mounting clip. (green arrow)

Models with 4-cylinder engine - Secondary air pump -Lift the pump up and off the bracket.
Figure 11

Models with 4-cylinder engine - Secondary air pump -Lift the pump up and off the bracket. You will have to push the pump toward the firewall to clear the plastic clip on the rear of the bracket. Then, remove the purge valve from the pump by pulling it straight up and off the mounting bracket. (green arrow) The purge valve is housed in a rubber mount, if it is stuck; lubricate it with dish soap to help get it off.

Models with 4-cylinder engine - Secondary air pump -Lift the secondary air pump off the mounting bracket and disconnect electrical connector by squeezing tabs and pulling is straight off.
Figure 12

Models with 4-cylinder engine - Secondary air pump -Lift the secondary air pump off the mounting bracket and disconnect electrical connector by squeezing tabs and pulling is straight off.

Models with 4-cylinder engine - Secondary air pump -With the air pump remove, you now have to remove the bracket to swap it over to the new pump.
Figure 13

Models with 4-cylinder engine - Secondary air pump -With the air pump remove, you now have to remove the bracket to swap it over to the new pump. Remove three 4mm Allen bolts through the holes in the bracket (green arrows)

Models with 4-cylinder engine - Secondary air pump -This photo shows one of the Allen bolts being removed.
Figure 14

Models with 4-cylinder engine - Secondary air pump -This photo shows one of the Allen bolts being removed. If the rubber insulators (yellow arrows) are worn, replace them too. To install the new pump, reverse the steps. Be sure to clip the wiring harness to the bracket and double check the hose routing.

Models with 4-cylinder engine - Secondary air pump solenoid - This secondary air pump solenoid is located near the oil filter on the intake manifold.
Figure 15

Models with 4-cylinder engine - Secondary air pump solenoid - This secondary air pump solenoid is located near the oil filter on the intake manifold. (green arrow)

Models with 4-cylinder engine - Secondary air pump solenoid - The replace it, start by pressing the wire release tab and pulling the electrical connector straight off.
Figure 16

Models with 4-cylinder engine - Secondary air pump solenoid - The replace it, start by pressing the wire release tab and pulling the electrical connector straight off.

Models with 4-cylinder engine - Secondary air pump solenoid - Next you have to slide the solenoid off the mounting bracket.
Figure 17

Models with 4-cylinder engine - Secondary air pump solenoid - Next you have to slide the solenoid off the mounting bracket. To do this, I use a small flathead screwdriver to press the release tab, then slide it off toward the left side of the vehicle. See next photo for what the tab you have to disconnect looks like.

Models with 4-cylinder engine - Secondary air pump solenoid - The green arrow points to the plastic tab you unclipped in the previous step.
Figure 18

Models with 4-cylinder engine - Secondary air pump solenoid - The green arrow points to the plastic tab you unclipped in the previous step. Once unclipped, disconnect both vacuum hoses from the solenoid (yellow arrows), then remove solenoid from the engine. Install new solenoid in the reverse order of removing. Be sure the new solenoid snaps into place when installing.

Models with 4-cylinder engine - Secondary air pump check valve - The secondary air pump check valve is located at the right front of the cylinder head.
Figure 19

Models with 4-cylinder engine - Secondary air pump check valve - The secondary air pump check valve is located at the right front of the cylinder head. The first step for removing the secondary air valve is to disconnect the air pipe. Next you have to disconnect the secondary air valve from the pump. Squeeze the release tabs, and then pull the pipe straight off the secondary air valve to remove.

Models with 4-cylinder engine - Secondary air pump check valve - Next you will have to remove the washer fluid reservoir to access the check valve.
Figure 20

Models with 4-cylinder engine - Secondary air pump check valve - Next you will have to remove the washer fluid reservoir to access the check valve. You can suction out the fluid if you want, but if you leave the lines connected and place the reservoir out of the way, you can leave the fluid in it. Using a flathead screwdriver, remove the reservoir mounting fastener.

Models with 4-cylinder engine - Secondary air pump check valve - Then lift the reservoir up and place it on the fender.
Figure 21

Models with 4-cylinder engine - Secondary air pump check valve - Then lift the reservoir up and place it on the fender. You now have access to the check valve (green arrow).

Models with 4-cylinder engine - Secondary air pump check valve - There is a small rubber hose that runs to the check valve (green arrow).
Figure 22

Models with 4-cylinder engine - Secondary air pump check valve - There is a small rubber hose that runs to the check valve (green arrow). You can replace it if needed by removing the clamps and then the hose.

Models with 4-cylinder engine - Secondary air pump check valve - Too remove the clamps, lever the clamp in the same area as shown in photo using a small flathead screwdriver.
Figure 23

Models with 4-cylinder engine - Secondary air pump check valve - Too remove the clamps, lever the clamp in the same area as shown in photo using a small flathead screwdriver. This will release the clamp. Unclip both clamps, then slide hose down to remove from valve inlet, then slide off of pipe to remove.

Models with 4-cylinder engine - Secondary air pump check valve - Install new hose, then using a pair of hose clamp pliers, refasten the hose clamp.
Figure 24

Models with 4-cylinder engine - Secondary air pump check valve - Install new hose, then using a pair of hose clamp pliers, refasten the hose clamp. You will need special pliers to do this. The plier is similar to a CV boot plier.

Models with 4-cylinder engine - Secondary air pump check valve - To remove the check valve, start by pulling the vacuum line (green arrow) off the valve.
Figure 25

Models with 4-cylinder engine - Secondary air pump check valve - To remove the check valve, start by pulling the vacuum line (green arrow) off the valve. If the vacuum line is cracked or worn, replace it. This is the vacuum line that runs to the solenoid, if it fails a fault code will be set.

Models with 4-cylinder engine - Secondary air pump check valve - Next remove the two 10mm nuts (green arrows) from the bottom of the check valve.
Figure 26

Models with 4-cylinder engine - Secondary air pump check valve - Next remove the two 10mm nuts (green arrows) from the bottom of the check valve. I find it is easiest to do this using a ratcheting wrench.

Models with 4-cylinder engine - Secondary air pump check valve - You can now remove the check valve from the pipe.
Figure 27

Models with 4-cylinder engine - Secondary air pump check valve - You can now remove the check valve from the pipe. Once removed clean the sealing surface of the pipe. Install new secondary air valve with new gasket and tighten fasteners. Then install the vacuum line and secondary air pipe. Reinstall the washer fluid reservoir. Check operation of secondary air components and clear DME fault codes using a BMW scan tool.

Models with 6-cylinder engine - Secondary air pump -BMW Z3 models with a 6-cylinder engine have the secondary air pump mounted in the right rear of the engine compartment.
Figure 28

Models with 6-cylinder engine - Secondary air pump -BMW Z3 models with a 6-cylinder engine have the secondary air pump mounted in the right rear of the engine compartment. (green arrow). Replacing it is quite similar to the 4-cylinder model.

Models with 6-cylinder engine - Secondary air pump -First you have to disconnect the secondary air pipe from the pump.
Figure 29

Models with 6-cylinder engine - Secondary air pump -First you have to disconnect the secondary air pipe from the pump. Squeeze the release tabs (green arrows), then pull the pipe straight off the secondary air valve to remove.

Models with 6-cylinder engine - Secondary air pump -Now it is time to unbolt the secondary air pump.
Figure 30

Models with 6-cylinder engine - Secondary air pump -Now it is time to unbolt the secondary air pump. You will have to lift it up to disconnect the electrical at the bottom. Start by removing the two 13mm nuts (green arrows) that secure the pump to the support bracket. Lift the pump up and off the bracket. Once removed, you can remove the inlet air pipe (yellow arrow) from the pipe by squeezing the release tabs and pulling it straight off.

Models with 6-cylinder engine - Secondary air pump -Lift the secondary air pump off bracket and disconnect electrical connector by squeezing tabs and pulling it straight off.
Figure 31

Models with 6-cylinder engine - Secondary air pump -Lift the secondary air pump off bracket and disconnect electrical connector by squeezing tabs and pulling it straight off.

Models with 6-cylinder engine - Secondary air pump -With the air pump remove, you now have to remove the bracket to swap it over to the new pump.
Figure 32

Models with 6-cylinder engine - Secondary air pump -With the air pump remove, you now have to remove the bracket to swap it over to the new pump. Remove three 4mm Allen bolts through the holes in the bracket (green arrows)

Models with 6-cylinder engine - Secondary air pump -This photo shows one of the Allen bolts being removed.
Figure 33

Models with 6-cylinder engine - Secondary air pump -This photo shows one of the Allen bolts being removed. If the rubber insulators (yellow arrows) are worn, replace them too. To install the new pump, reverse the steps. Be sure the wiring harness and pipes are routed as they were before.

Models with 6-cylinder engine - Secondary air pump check valve-The secondary air check valve is located at the right front of the cylinder head.
Figure 34

Models with 6-cylinder engine - Secondary air pump check valve-The secondary air check valve is located at the right front of the cylinder head. To access it, you have to remove the washer fluid reservoir.

Models with 6-cylinder engine - Secondary air pump check valve-First you will have to remove the washer fluid reservoir to access the check valve.
Figure 35

Models with 6-cylinder engine - Secondary air pump check valve-First you will have to remove the washer fluid reservoir to access the check valve. You can suction out the fluid if you want, but if you leave the lines connected and place the reservoir of the way, you can leave the fluid in it. Using a flathead screwdriver, remove the reservoir mounting fastener. Then lift the reservoir up and place it on the fender. You now have access to the check valve. Working at right front of cylinder head, squeeze the release tabs, and then pull the air pipe straight off the secondary air valve to remove.

Models with 6-cylinder engine - Secondary air pump check valve-Next, remove two 10mm secondary air valve fasteners.
Figure 36

Models with 6-cylinder engine - Secondary air pump check valve-Next, remove two 10mm secondary air valve fasteners. (green arrows) Then remove valve from cylinder head. (This photo shows a similar model with a similar secondary air valve, replacing it is the same.)

Models with 6-cylinder engine - Secondary air pump check valve-Clean valve sealing surface on cylinder head and remove all old gasket debris.
Figure 37

Models with 6-cylinder engine - Secondary air pump check valve-Clean valve sealing surface on cylinder head and remove all old gasket debris. Be careful not to drop any debris into valve opening on cylinder head. Install new secondary air valve with new gasket and tighten fasteners. Then install secondary air pump and hose. Check operation of secondary air components and clear DME fault codes using a BMW scan tool.

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Comments and Suggestions:
LJ Comments: Dealer also replaced fuel injector with no help.
September 2, 2015
  Followup from the Pelican Staff: See my earlier reply. - Nick at Pelican Parts  
LJ Comments: replaced plugs and coils with no help. took to dealer and they checked compression was good and swapped plug and coils with other cyl. no help runs great on the road and check engine lite even went out on a 2 day trip. Came back oh later. could it be a chip or computer issue?
September 2, 2015
  Followup from the Pelican Staff: To have a misfire, part of the combustion process has to be faulty, spark, fuel or compression. Regardless if DME, fuel pump or coil, you have to pinpoint which of the three items is faulty before replacing parts.. - Nick at Pelican Parts  
LJ Comments: Those have all been checked OK. 3.0 ENGINE w/6sp. trans.
August 29, 2015
  Followup from the Pelican Staff: If they were checked and found to be good, you would not have a misfire. Rerun your tests. - Nick at Pelican Parts  
LJ Comments: Would the secondary air system be the cause of check engine lite and # 2 cyl misfire code and actual missing when cold, but runs great as long as you don't let it idle when cold on a 2003 Z4? BMW dealer can't identify the problem.
August 27, 2015
  Followup from the Pelican Staff: No. I would check spark, fuel and compression on all cylinders.
- Nick at Pelican Parts
 

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