With Plastic Intake Manifold
Fuel Pump, Checking
Special tools, testers and auxiliary items required
• Hand held remote control (jumper).
• Multimeter.
• Voltage tester
• Measuring container
• Wiring diagram
Test conditions
• Read safety precautions before beginning work.
• Maintain clean working conditions.
• Battery voltage at least 12.5 V
• Fuse for Fuel Pump (FP) OK.
• Fuel Pump (FP) Control Module (J538) OK.
• Low Fuel Pressure Sensor (G410) OK.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Function and Voltage Supply, Checking
- Switch ignition on. Fuel pump must run audibly for approx. 2 Seconds.
- Switch off ignition.
If Fuel Pump (FP) does not start up:
- Remove nuts - 1 - on right side of fuel delivery unit cover. If necessary, remove backrest support - 2 - or mounting bracket:
- Disconnect connector from Fuel Pump (FP) Control Module (J538) - 5 -.
- Switch ignition on.
- Check voltage supply between connector terminals - 3 - and - 4 - using low voltage tester. LED must light up.
- Switch off ignition.
LED does not light up:
- Locate and repair open circuit.
LED lights up (voltage supply OK):
CAUTION!
Fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
- Remove high pressure in fuel system.
- Remove fuel supply line - 1 -, auxiliary heater fuel line - 2 -, fuel pump connector - 3 - and vent line - 4 -.
• Press in securing ring to disengage the fuel line.
- Open locking ring using wrench (T10202).
- Check whether electrical wires between flange and Fuel Pump (FP) are connected.
If no open circuits are found:
- Fuel Pump (FP) faulty, replace fuel delivery unit.
- 4.2 Liter V8 4V Engine Mechanical, Fuel Injection & Ignition, Engine Code(s): BAR; Rep. Gr.20; Removal and installation procedures.
Fuel Pressure, Checking
- Remove high pressure in fuel system.
CAUTION!
Fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully loosening the union nut.
- Place a cloth around connection and loosen union nut - arrow - to reduce fuel pressure.
- Then tighten threaded connection again.
- Connect a Pressure Tester with Adapter, as shown.
- Make sure hose clamps are seated securely.
- Open shut-off valve of pressure gauge set. The lever points in the direction of flow.
- Remove nuts - 1 - on right side of fuel delivery unit cover. If necessary, remove backrest support - 2 - or mounting bracket:
- Disconnect connector from Fuel Pump (FP) Control Module (J538) - 5 -.
- Disconnect harness connector - 3 - from flange of fuel delivery unit.
- Connect Hand held remote starter (jumper) with adapter cables from connector test kit to terminal - 1(+) - of Fuel Pump (FP) and to terminal - 3(+) - of harness connector of Fuel Pump (FP) Control Module (J538).
- Connect terminals - 4(-) - of harness connector and - 4(-) - of Fuel Pump (FP) using an adapter cable from connector test kit.
- Switch ignition on.
- Operate Hand held remote starter (jumper) and observe display of pressure tester while doing this.
Fuel pressure must increase up to a maximum pressure of 6 bar.
• When releasing control button of remote control, fuel pressure decreases to approx. 5.6 bar.
If fuel pressure is OK, check Residual Pressure.
If specification is exceeded:
- Pressure relief valve in sensor flange faulty, replace sensor flange.
If specification is not obtained:
- Check fuel lines for possible restrictions (kinks) or blockages.
- Check all fuel lines in fuel tank for leaks.
- Check fuel filter for leaks.
If no malfunction can be found:
- Replace sensor flange with pressure relief valve.
- Repeat test.
If fuel pressure is not obtained again:
- Fuel Pump (FP) faulty, replace fuel delivery unit.
Residual Pressure, Checking
Test sequence
- Watch pressure drop on gauge. After 10 minutes pressure must not drop below a 4.0 bar decrease.
If pressure drops below 4.0 bar:
- Operate Hand held remote starter (jumper) while doing this, observe display of pressure tester.
Fuel pressure must increase up to a maximum pressure of 6 bar.
- Release control button of Hand held remote starter (jumper) and immediately close shut-off valve of pressure tester. Then lever the points perpendicular to flow direction - arrow -.
• When releasing control button of Hand held remote starter (jumper), fuel pressure decreases to approx. 5.6 bar.
If pressure drops below 4.0 bar again:
(Leak on fuel tank side)
- Check connections to fuel tank for leaks.
If no malfunction can be found:
- Check fuel filter for leaks.
- Check fuel line to sensor flange for leaks.
- Check all additional fuel lines in fuel tank for leaks.
If no malfunctions are found on fuel line:
- Pressure relief valve in fuel delivery unit flange faulty.
- Replace sensor flange which contains the pressure relief valve.
Delivery Rate, Checking
- Remove high pressure in fuel system.
CAUTION!
Fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully loosening the union nut.
- Connect Pressure Gauge with adapter, as shown.
- However, do not connect ends of Hose to fuel rail connector.
- Hold end of Hose in a measuring container.
- Open shut-off valve of pressure gauge. The lever points in direction of flow.
- Switch ignition on.
- Operate Hand held remote starter (jumper). Slowly close shut-off tap, until pressure gauge shows 4 bar fuel pressure. From this point on do not move position of shut-off tap.
- Do not operate Hand held remote starter (jumper) any more.
- Empty measuring container.
- Operate remote control for 15 Seconds.
- Compare quantity of fuel delivered with minimum delivery rate in diagram (cm3/15s).
• Voltage at fuel pump with engine stopped and pump running is approx. 2 volts less than battery voltage.
If minimum delivery rate is not attained:
- Check fuel lines for possible restrictions (kinks) or blockages.
If lines are OK:
- Replace fuel filter.
- Repeat test.
If specified value is again not obtained:
- Fuel Pump (FP) faulty, replace fuel delivery unit.
If delivery rate has been attained but specified value is intermittent:
- Check Fuel Pump (FP) current draw. refer to.
Current Draw, Checking
- Check current draw of fuel pump as follows:
- Reconnect all disconnected fuel lines.
- Connect a multimeter with electrical current probe to wire of 4-pin connector terminal - 1 - - arrow - from wiring harness to Fuel Pump (FP) unit, right.
- Start engine and run at idle speed.
- Measure current draw of fuel pump. Specified value: max. 11 amps.
If current draw is exceeded:
- Fuel Pump (FP) faulty, replace fuel delivery unit.
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.