hello everyone this is my first time on this site, i have a 2003 landrover discovery, ive been hearing a loud suction sound when i start the truck coming from the Sai pump when i remove the Sai vaccum solenoid valve the noise stops. Does any one know how to fix the problem or whats causing it

 

It may not be a problem. The SAI pump is supposed to run on first start of the day (temperature dependent) It will sound like a vacuum cleaner for a while and then shut off. it's purpose is to reduce emissions on cold starts.

 

The filter may be clogged.
In the "write up" section on the DII page is a "how to" replace that filter.

 

check filter, but also squeeze the housing when its running, see if applying pressure makes the loud noise go down to tollerable levels, if so, the rivets have stretched or popped and airs shooting back out between the housing (you can also feel it easily) causing the noise to be rather loud. happened to mine almost a year ago, i just unplugged the ****er and let it be. ive been meaning to try silicon or epoxy around the seems to see if itll work, im sure it would i dont think it puts out too many psi... certainly cheaper then gettin a new pump. also, ive heard that you can drilled out the rivets and just replace them with nuts/bolts and be done with it.

 

alright i'll give these things a try to see if they'll work thank you

 

I've read that if the solenoid goes bad, it won't actually let the air pump to where it needs to go, causing them to get noisy... I have not personally experienced this, but I'd be tempted to put a $35 solenoid on it before I'd take the pump apart to get to the filter. Or I'd at least attempt to test the solenoid.

Solenoid - Secondary Air Injection (Genuine Part # YDJ100000) - Land Rover miscellaneous from Atlantic British

 

you could unplug the sai pump and when the car starts, if the valves are working youll have an exhuast leak deap tone noise instead... quick free check

 

Hi All,
Just came across this thread through google search - sorry to parachute in.

My 04 disco had the noisy sai thing going on and now the pump doesn't even come on.

I have the RAVE manual but I cannot find where the solenoid for the sai pump is. If the solenoid goes I am assuming the pump will not turn on?

GRANDKODIAK stated - "you could unplug the sai pump and when the car starts, if the valves are working youll have an exhuast leak deap tone noise instead"

Well I have this "exhaust leak deep tone noise", I thought my manifold might be loose, but the sound goes away after a few minutes.

I know not having a functional SAI isn't the end of the world, but in British Columbia we have very strict AirCare laws....

Is there a way I could test the SAI pump to see if it still works?

ANy help is much appreciated - Paul

 

C0570 - pin 3 , black/orange - ground this momentarily and pump should turn on. This wire goes to ECU, where a ground is switched on/off to operate relay. Don't unplug, just shove a ground lead on it or pierce insulation with a straight pin. Should hear relay click in and pump run.

See pix.

 

Secondary Air Injection System The secondary air injection (SAI) system comprises the following components: • Secondary air injection pump • SAIvacuum solenoid valve • SAIcontrol valves (2 off,1 for each bank of cylinders) • SAIpump relay • Vacuum reservoir • Vacuum harness and pipes The secondary air injection system is used to limit the emission of carbon monoxide (CO) and hydrocarbons (HCs) that are prevalent in the exhaust during cold starting of a spark ignition engine. The concentration of hydrocarbons experienced during cold starting at low temperatures are particularly high until the engine and catalytic converter reach normal operating temperature. The lower the cold start temperature,the greater the prevalence of hydrocarbons emitted from the engine.

There are several reasons for the increase of HC emissions at low cold start temperatures, including the tendency for fuel to be deposited on the cylinder walls, which is then displaced during the piston cycle and expunged during the exhaust stroke. As the engine warms up through operation, the cylinder walls no longer retain afilm of fuel and most of the hydrocarbons will be burnt off during the combustion process.

The SAIpump is used to provide a supply of air into the exhaust ports in the cylinder head, onto the back of the exhaust valves, during the cold start period.The hot unburnt fuel particles leaving the combustion chamber mix with the air injected into the exhaust ports and immediately combust. This subsequent combustion of the unburnt and partially burnt CO and HC particles help to reduce the emission of these pollutants from the exhaust system. The additional heat generated in the exhaust manifold also provides rapid heating of the exhaust system catalytic converters. The additional oxygen which is delivered to the catalytic converters also generate an exothermic reaction which causes the catalytic converters to 'light off' quickly.

The catalytic converters only start to provide effective treatment of emission pollutants when they reach an operating temperature of approximately 250 °C (482°F) and need to be between temperatures of 400 °C (752 °F) and 800 °C (1472 °F) for optimum efficiency. Consequently,the heat produced by the secondary air injection "after burning", reduces the time delay before the catalysts reach an efficient operatingtemperature.

The engine control module (ECM) checks the engine coolant temperature when the engine is started,and if it is below 60 °C (131 °F) , the SAI pump is started. Secondary air injection will remain operational for a period controlled by the ECM (76 seconds for NAS vehicles, 64 seconds for EU-3 vehicles). The SAIpump operation can be cut short due to excessive engine speed or load.

Air from the SAIpump is supplied to the SAI control valves viapipework and an intermediate T-piece which splits the air flow evenly to each bank.

At the same time the secondary air pump is started, the ECM operates a SAI vacuum solenoid valve, which opens to allow vacuum from the reservoir to be applied to the vacuum operated SAI control valves on eachside of the engine. When the vacuum is applied to the SAI control valves, they open simultaneously to allow the air from the SAI pump through to the exhaust ports. Secondary air is injected into the inner most exhaust ports on each bank.

When the ECM breaks the ground circuit to de-energise the SAI vacuum solenoid valve, the vacuum supply to the SAI control valves is cut off and the valves close to prevent further air being injected into the exhaust manifold. At the same time as the SAI vacuum solenoid valve is closed, the ECM opens the ground circuit to the SAI pump relay, to stop the SAI pump.

A vacuum reservoir is included in the vacuum line between the intake manifold and the SAIvacuum solenoid valve. This prevents changes in vacuum pressure from the intake manifold being passed on to cause fluctuations of the secondary air injection solenoid valve. The vacuum reservoir contains a one way valve and ensures a constant vacuum is available for the SAI vacuum solenoid valve operation. This is particularly important when the vehicle is at high altitude. Secondary Air Injection (SAI) Pump The SAIpump is attached to a bracket at the rear RH side of the engine compartment and is fixed to the bracket by three studs and nuts. The pump is electrically powered from a 12 V battery supply via adedicated relay and supplies approximately 35 kg/hr of air when the vehicle is at idle in Neutral/Park on astart from 20 °C (68 °F) .

Air is drawn into the pump through vents in its front cover and is then passed through afoam filter to remove particulates before air injection. The air is delivered to the exhaust manifold on each side of the engine through a combination of plastic and metal pipes.

The air delivery pipe is a flexible plastic type, and is connected to the air pump outlet via a plastic quick-fit connector. The other end of the flexible plastic pipe connects to the fixed metal pipework via a short rubber hose. The part of the flexible plastic pipe which is most vulnerable to engine generated heat is protected by heat reflective sleeving. The metal delivery pipe has a fabricated T-piece included where the pressurised air is split for delivery to each exhaust manifold via the SAIcontrol valves.

The pipes from the T-piece to each of the SAI control valves are approximately the same length, so that the pressure and mass of the air delivered to each bank will be equal. The ends of the pipes are connected to the inlet port of each SAI control valve through short rubber hose connections.

The T-piece is mounted at the rear of the engine (by the ignition coils) and features a welded mounting bracket which is fixed to the engine by two studs and nuts.

The foam filter in the air intake of the SAI pump provides noise reduction and protects the pump from damage due to particulate contamination. In addition, the pump is fitted on rubber mountings to help prevent noise which is generated by pump operation from being transmitted through the vehicle body into the passenger compartment.

If the secondary air injection pump malfunctions, the following fault codes may be stored in the ECM diagnostic memory, which can be retrieved using 'Testbook': P-code Description P0418 Secondary air injection pump powerstage fault (e.g. - SAI pump relay fault/SAI pump or relay not connected/open circuit/harness damage). Secondary Air Injection (SAI) Pump Relay The secondary air injection pump relay is located in the engine compartment fusebox. The engine control module (ECM) is used to control the operation of the SAI pump viathe SAI pump relay. Power to the coil of the relay is supplied from the vehicle battery via the main relay and the ground connection to the coil is via the ECM.

Power to the SAI pump relay contacts is viafusible link FL2 which is located in the engine compartment fusebox.

Secondary Air Injection (SAI) Vacuum Solenoid Valve The SAIvacuum solenoid valve is located at the rear LH side of the engine and is electrically operated under the control of the ECM. The SAI vacuum solenoid valve is mounted on a bracket together with the EVAP system purge valve.

Vacuum to the SAIvacuum solenoid valve is provided from the intake manifold depression via a vacuum reservoir. A small bore vacuum hose with rubber elbow connections at each end provides the vacuum route between the vacuum reservoir and SAIvacuum solenoid valve. A further small bore vacuum hose with a larger size elbow connector is used to connect the SAI vacuum solenoid valve to the SAI control valves on each side of the engine viaan intermediate connection. The SAI vacuum solenoid valve port to the SAI control valves is located at a right angle to the port to the vacuum reservoir.

The intermediate connection in the vacuum supply line is used to split the vacuum equally between the two SAI control valves. The vacuum hose intermediate connection is located midpoint in front of the inlet manifold. All vacuum hose lines are protected by flexible plastic sleeving.

Electrical connection to the SAI vacuum solenoid valve is via a 2-pin connector. A 12 V electrical power supply to the SAI vacuum solenoid valve is provided via the Main relay and Fuse 2 in the engine compartment fusebox. The ground connection is viathe ECM which controls the SAI vacuum solenoid valve operation. Note that the harness connector to the SAIsolenoid valve is grey, and must not be confused with the harness connector to the EVAP system purge valve which is black.

The ECM switches on the SAI vacuum solenoid valve at the same time as initiating SAI pump operation. When the SAIvacuum solenoid valve is open, a steady vacuum supply is allowed through to open the two vacuum operated SAI control valves. When the ECM breaks the earth path to the SAI vacuum solenoid valve, the valve closes and immediately shuts off the vacuum supply to the two SAI control valves at the same time as the SAI pump operation is terminated.





If the SAIvacuum solenoid valve malfunctions, the following fault codes may be stored in the ECM diagnostic memory, which can be retrieved using 'Testbook': P-code Description P0413 SAIvacuum solenoid valve not connected, open circuit P0414 SAIvacuum solenoid valve short circuit to ground P0412 SAIvacuum solenoid valve powerstage fault - harness damage, short circuit to battery supply voltage

SAI Control Valves The SAIcontrol valves are located on brackets at each side of the engine. The air injection supply pipes connect to a large bore port on the side of each SAI control valve via ashort rubber connection hose. A small bore vacuum port is located on each SAI control valve at the opposite side to the air injection supply port. The vacuum supply to each vacuum operated SAI control valve is through small bore nylon hoses from the SAI vacuum solenoid valve. Anintermediate connector is included in the vacuum supply line to split the vacuum applied to each vacuum operated valve, so that both valves open and close simultaneously

When a vacuum is applied to the SAI control valves, the valve opens to allow the pressurised air from the SAI pump through to the exhaust manifolds. The injection air is output from each SAI control valve through a port in the bottom of each unit. A metal pipe connects between the output port of each SAI control valve and each exhaust manifold via an intermediate T-piece. The T-piece splits the pressurised air delivered to ports at the outer side of the two centre exhaust ports on each cylinder head. The pipes between the T-piece and the exhaust manifold are enclosed in thermal sleeving to protect the surrounding components from the very high heat of the exhaust gas, particularly at high engine speeds and loads.

When the SAI vacuum solenoid valve is de-energised, the vacuum supply line opens to atmosphere, this causes the vacuum operated valves to close automatically and completely to prevent further air injection.

If the vacuum operated SAI control valves malfunction, the following fault codes may be stored in the ECM diagnostic memory, which can be retrieved using 'Testbook': P-code Description P1412 SAIsystem fault (LH side) - air delivery not reaching catalysts P1414 SAIsystem fault (LH side) - air delivery not reaching catalysts P1413 SAIsystem fault (LH side) - air delivery not reaching catalysts P1415 SAIsystem fault (RH side) - air delivery not reaching catalysts P1417 SAIsystem fault (RH side) - air delivery not reaching catalysts P1416 SAIsystem fault (RH side) - air delivery not reaching catalysts The above system faults could be attributable to anything which might prevent air delivery to the exhaust manifolds (e.g. disconnected or blocked SAI delivery pipe, disconnected or blocked vacuum pipe etc.)

Vacuum Reservoir A vacuum reservoir is included in the vacuum supply line between the intake manifold and the SAI vacuum solenoid valve. The vacuum reservoir contains a one-way valve, to stop depression leaking back towards the intake manifold side. The reservoir holds a constant vacuum so that the SAI control valves open instantaneously as soon as the SAI solenoid valve is energised.

The vacuum reservoir is a plastic canister construction located on a bracket at the LH side of the engine compartment. It is important to ensure the reservoir is fitted in the correct orientation, and the correct vacuum hoses are attached to their corresponding ports. The one-way valve end of the vacuum reservoir (cap end, to inlet manifold) is fitted towards the rear of the vehicle.

A small bore nylon hose is used to connect the one-way valve end of the vacuum reservoir to a port on the RH side of the inlet manifold. A further hose connects between the other port on the vacuum reservoir and a port on the front of the SAI vacuum solenoid valve.


The SAIvacuum solenoid valve is located at the rear LH side of the engine and is electrically operated under the control of the ECM. The SAI vacuum solenoid valve is mounted on a bracket together with the EVAP system purge valve.

Vacuum to the SAIvacuum solenoid valve is provided from the intake manifold depression via a vacuum reservoir. A small bore vacuum hose with rubber elbow connections at each end provides the vacuum route between the vacuum reservoir and SAIvacuum solenoid valve. A further small bore vacuum hose with a larger size elbow connector is used to connect the SAI vacuum solenoid valve to the SAI control valves on each side of the engine viaan intermediate connection. The SAI vacuum solenoid valve port to the SAI control valves is located at a right angle to the port to the vacuum reservoir.

The intermediate connection in the vacuum supply line is used to split the vacuum equally between the two SAI control valves. The vacuum hose intermediate connection is located midpoint in front of the inlet manifold. All vacuum hose lines are protected by flexible plastic sleeving.

Electrical connection to the SAI vacuum solenoid valve is via a 2-pin connector. A 12V electrical power supply tothe SAI vacuum solenoid valve is provided via the Main relay and Fuse 2 in the engine compartment fusebox. The ground connection is viathe ECM which controls the SAI vacuum solenoid valve operation. Note that the harness connector to the SAIsolenoid valve is grey, and must not be confused with the harness connector to the EVAP system purge valve which is black.

The ECM switches on the SAI vacuum solenoid valve at the same time as initiating SAI pump operation. When the SAIvacuum solenoid valve is open, a steady vacuum supply is allowed through to open the two vacuum operated SAI control valves. When the ECM breaks the earth path to the SAI vacuum solenoid valve, the valve closes and immediately shuts off the vacuum supply to the two SAI control valves at the same time as the SAI pump operation is terminated.

If the SAIvacuum solenoid valve malfunctions, the following fault codes may be stored in the ECM diagnostic memory, which can be retrieved using 'Testbook':

P-code Description P0413 SAI vacuum solenoid valve not connected, open circuit P0414 SAI vacuum solenoid valve short circuit to ground P0412 SAI vacuum solenoid valve powerstage fault - harness damage, short circuit to battery supply voltage