SEAT Workshop Service and Repair Manuals

Fuel pump: verification Consult the equivalence table for tools and equipment according to applicability between Seat / VW / Audi / Skoda → Chapter

Special tools and workshop equipment required

t	Adaptor cable -SAT 1348/3-3-, see equivalent → Anchor

t	Wrench -T20207-see equivalent

t	V.A.G 1348 remote control -VAG 1348/3 A-

t	Pressure tester -VAG 1527B-

t	Auxiliary cable kit -VAG 1594C-

t	Digital multimeter -VAG 1715-

t	Pressure tester -VAG 1318-

t	Adapters -VAG 1318/1-

t	Adapters -VAG 1318/9-

t	Adapters -VAG 1318/11-

t	Adapters -VAG 1318/17-

t	Adapters -VAG 1318/23-

t	Torque wrench (40 ... 200 Nm) -V.A.G 1332-, see equivalent → Anchor

t  Step ladder t  Measuring container t  Current flow diagrams, electrical fault finding and fitting locations Operation and voltage supply: verification Test conditions: l  Battery voltage at least 11.5 V

l  SC 34 fuse from the fuse holder on the left-hand side of the insytrument panel, in good condition. Fuse installation → Current flow diagrams, Electrical fault finding and Fitting locations l  All consumer electrics, for example: lights, heated rear window, should be off. l  In vehicles fitted with air conditioning (heating), this must be disconnected. l  Ignition OFF   Note Note instructions on crash fuel cut-off → Chapter. –  Move rear seat forward.

–  Unclip fastening notches -arrows- and remove the protector from the fuel supply unit. –  Switch ignition on. The fuel pump should be heard to be operating for a few moments.   Note The fuel pump runs very quietly. –  Switch the ignition off. If the fuel pump does not run:

–  Using the auxiliary cables of the auxiliary measuring set -V.A.G 1594C-, connect the remote control -VAG 1348/3A- to contact -5- of the fuel pump and to the (+) positive terminal of the battery –  Join contact -5- of the connector and contact -1- of the fuel pump using the auxiliary cables of the auxiliary measuring set -V.A.G 1594C-. –  Press remote control switch. Fuel pump runs: –  Check activation of the fuel pump relay -J17- according to electrical diagram → Current flow diagrams, Electrical fault finding and Fitting locations. Fuel pump does not run: –  Extract the 5 pin terminal connector from the fuel delivery unit flange

–  Connect voltage tester -V.A.G 1527 B- to the outer connector contacts using auxiliary cables fromadapter set -V.A.G 1594 C-. –  Switch on the ignition. The LED must light. If the LED does not light up: –  Locate and eliminate open circuit using current flow diagram → Current flow diagrams, Electrical fault finding and Fitting locations. If the diode lights (voltage supply is OK):

–  Unscrew union nut using key -T20207-. –  Check that the electrical wires between flange and fuel pump are connected. If there is cable integrity: –  Fuel pump is defective, renew fuel delivery unit → Chapter. Fuel delivery quantity: verification Test conditions: l  Voltage supply OK → Anchor l  Fuel pressure regulator and retention pressure correct → Chapter l  Fuel filter correct. Checking procedure –  Remove cover from fuse holder.

–  Remove fuse F34 for the fuel pump in the fuse holder. Fuse installation → Current flow diagrams, Electrical fault finding and Fitting locations –  Connect remote control -VAG 1348/3A- with adapter cable -SAT 1348/3-3- to lower contact to fuel pump and battery positive (+).   Note The following operation is to make the fuel pump run when the engine is stopped. –  Remove filler cap from fuel tank filler neck.   Note The delivery rate of the fuel pump is measured at a pressure of 4 bar. Therefore, check fuel pressure before measuring delivery rate.   WARNING Fuel system is under pressure! Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before opening the system place a cloth around the connection. Then release pressure by carefully pulling fuel hose from connection.

–  Disconnect the fuel return line -1-. Push the buttons on the fuel hose coupling for this purpose. –  Connect adaptor -VAG 1318/17- to pressure tester and place adaptor end in a measuring container. –  Operate the remote control -VAG 1348/3A- for 5 seconds, to fill the fuel filter. –  Empty measuring container. –  The quantity of fuel delivered by the fuel pump is dependent upon voltage. Therefore connect multimeter to the battery. –  Operate the remote control -VAG 1348/3A- for 30 seconds, and measure fuel pump voltage.

–  Compare the fuel flow with specification. 1)  Minimum delivery cm3/30 s 2)  Voltage on the fuel pump when the engine is stationary and with running pump (approx. 2 volt under battery voltage). Readout example: During the test, the battery voltage is measured at 12.5 volts. As the voltage at the pump is about 2 V less than the battery, this will equate to a minimum delivery of 600 cm3/30 s. If the minimum delivery rate is not attained: –  Check the fuel pipes to the filter for possible restrictions (kinks) or blockages. If the fuel line is not damaged: –  Check the flow of fuel before the filter.   WARNING Fuel supply pipes are pressurised. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then eliminate the pressure by carefully separating the pipe.

–  Remove the supply line -1- from the fuel filter inlet. Push the buttons on the fuel hose coupling for this purpose. –  Connect fuel supply pipe to pressure tester -VAG 1318-, using adapter -VAG 1318/17-. –  Connect adapter -V.A.G 1318/1- to adapter -V.A.G 1318/11- of pressure tester and insert in a measuring container. –  Open cut-off tap on pressure gauge -VAG 1318-. The lever then points in through-flow direction -A-. –  Operate the remote control -V.A.G 1348/3A-. In doing so, slowly close the cut-off tap until 4 bar is shown on the manometer. From here on, do not change position of shut-off tap. –  Empty measuring container. –  Activate remote control again for 30 seconds. Compare the flow with the first value measured. If the minimum delivery rate is now attained: –  Replace fuel filter → Chapter. If the minimum delivery rate is again not attained: –  Remove the fuel delivery unit and check the strainer filter for soiling → Chapter. Only when up to now no fault has been detected: –  Renew the fuel delivery unit → Chapter. –  Reconnect all disconnected fuel pipes. –  Purge the fuel system → Chapter. If the delivery quantity has been attained, but nevertheless you suspect a fuel supply system fault (e.g. intermittent failure of fuel supply system): –  Check the current draw of the fuel pump as follows:

–  Connect multi-metre -V.A.G 1715- with crocodile clip to wiring to contact 1 -arrow- of 5-pin connector. –  Start engine and run at idling speed. –  Measure the power consumption of the fuel pump: t  Set value: max. 5 A   Note If there is a temporary fuel system fault, the check can also be carried out during a test drive, with the help of a second person. If the current draw is exceeded: –  Replace the fuel delivery unit → Chapter. Fuel pump retention valve: verification Test conditions: l  The V.A.G 1348 remote control -V.A.G 1348/3A- is still connected. l  The pressure gauge K-Jetronic -V.A.G 1318- is connected. Checking procedure

–  Using the auxiliary cables of the auxiliary measuring set -V.A.G 1594C-, connect the remote control -VAG 1348/3A- to contact -5- of the fuel pump and to the (+) positive terminal of the battery –  Join contact -5- of the connector and contact -1- of the fuel pump using the auxiliary cables of the auxiliary measuring set -V.A.G 1594C-.   WARNING Fuel supply pipes are pressurised. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then eliminate the pressure by carefully separating the pipe.

–  Remove the supply line -1- from the fuel filter. Push the buttons on the fuel hose coupling for this purpose. –  Connect the pressure gauge -VAG 1318- to the fuel filter with the help of the adaptor -VAG 1318/17-. –  Connect adaptor -VAG 1318/11- and -VAG 1318/1- to pressure tester -VAG 1318- and place adaptor end in a measuring container. –  Close cut-off tap of pressure tester (lever at right angles to direction of flow- position -B-). –  Operate remote control at short intervals until a pressure of 4 bar has built up.   WARNING Fuel may splash when opening the shut-off valve. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Place a container under the free coupling of the pressure gauge. –  If pressure builds up too high, lower excess pressure by carefully opening the shut-off tap. –  Observe pressure drop on pressure gauge -VAG 1318-. After 10 minutes the pressure must not drop below 3 bar. If the pressure drops further: –  Check pipe connections for leaks. If no fault in lines is detected: –  Fuel pump is defective, renew fuel delivery unit . Checking fuel gauge sender -G- Checking procedure –  Move rear seat forward.

–  Unclip fastening notches -arrows- and remove the protector from the fuel supply unit.

–  Disconnect the 5-pin connector terminal -1- from the fuel pump.

–  Connect the multimeter and measure the resistance between contacts -2- and -3-.

Sender fitted	Sender on the lower limit	Sender on the upper limit
Fuel gauge sender -G-	270 Ω, approximately	70 Ω, approximately

Note t  To test the resistance (values corresponding to “tank full” or “tank empty”, the fuel supply unit must be removed → Chapter and the sender float moved all the way to its top or bottom positions. t  If you get the value 0 Ω, a short exists; the value ∞ Ω indicates a short in the wire. t  With the fuel level indicator sender -G- removed and, due to the large floater range of movement, the following values are obtained:

Sender removed	Sender on the lower limit	Sender on the upper limit
Fuel gauge sender -G-	290 Ω, approximately	60 Ω, approximately

–  Connect the multimeter and measure the resistance between contacts -3- and -4-.

Sender fitted or removed	Sender in any position
Fuel gauge sender -G-	340 Ω, approximately

Install in reverse order.