LB. Engine Will Not Rev

LB. The Engine Will Not Rev or is Sluggish

Intermittent faults
If symptoms occur intermittently the Volvo ST can help.

LB1

Checking The Diagnostic Trouble Codes (DTCs)

If DTC 2-1-4 is not logged
^ Continue with Mechanical overview LB2.

If DTC 2-1-4 is logged
Cars with automatic transmission:
^ Continue with LB7: If DTC 2-1-4 is logged (cars with automatic transmission).
Cars with manual gearboxes:
^ Continue with LB8: If DTC 2-1-4 is logged (cars with manual gearboxes).

LB2




Mechanical Overview
- Check the camshaft position relative to the crankshaft.
- Check that the air intake and air filter are not clogged.
- Check that the exhaust system is not clogged.

If camshaft position, air intake and air filter are OK
^ Check the RPM sensor connector LB3.

LB3




Checking The RPM Sensor Connector
- Take apart the RPM sensor connector.
- Carefully scrape away dirt and deposits in the connector and clean the terminals.
- Grease the connector. Use P/N 1161417.
- Put the connector together.
- Check that the RPM sensor is properly located in its bracket.

If the connector and RPM sensor are OK
^ Check the tank pump resistance LB4.

LB4




Checking The Tank Pump Resistance
- Ignition off.
- Take apart the HO2S 2-pole connector.
- Disconnect interior lighting (760/960 fuse 26, 740/940 fuse 5)
- Remove fuse 11 and check that it is intact.
Connect an ohmmeter between the lower terminal on fuse 11 and GND (760/960 fuse 30 left terminal).
Non-turbo: The ohmmeter should read approx. 8 ohms.
Turbo: The ohmmeter should read approx. 4 ohms.

If this value is OK
^ Check the tank pump LB5.

If the reading is infinite resistance
^ Check the wiring and connections between fuse 11 and the tank pump for breaks in accordance with NA2. NA. Checking the Wiring

If the reading is 0 ohms.
^ Check the wiring between fuse 11 and the tank pump for grounding in accordance with NA3. NA. Checking the Wiring

If the reading is incorrect
^ Check the tank pump connections and GND point for contact resistance in accordance with NA6. NA. Checking the Wiring
If the connections and GND point are OK: Try using a new tank pump.

- Reconnect the HO2S connector
- Reconnect interior lighting.

LB5




Checking The Tank Pump
- Ignition on.
Listen to hear if the tank pump is Operating.
The tank pump should pump for about three seconds after the ignition has been switched on.
On certain version of the B230 F 1990 model the tank pump does not start when the ignition is switched on.
^ Operate the starter motor and listen to hear if the tank pump is operating.

If the tank pump is operating
^ X. Check the fuel pressure and residual pressure. X. Fuel Pressure and Residual Pressure
^ If the fuel pressure and residual pressure are OK: Continue with Connecting the test box LB6.

If the tank pump is not operating
^ Readings indicate that there is no fault in the tank pump electrical circuit. The tank pump has a mechanical fault: Try using a new tank pump.

LB6




Connecting The Test Box
- Connect the test box in accordance with P1-P4. P. Test Box, Signal Description
- Check all signals to MFI in accordance with PB. Signal description MFI PB. Signal Description MFI LH 2.4
and all signals to DI in accordance with PC. Signal description DI. PC. Signal Description DI EZ 116 K

LB7




If Diagnostic Trouble Code (DTC) 2-1-4 Is Logged (cars With Automatic Transmission)
- Delete the DTC.
- Check the RPM sensor connector for contact resistance in accordance with NA6. NA. Checking the Wiring
- Check that the RPM sensor is correctly located in its bracket.
- Run the engine at over 1500 rpm for 5 minutes.

If the DTC recurs
^ Check the drive plate for ovality.

If the DTC does not recur
^ The fault took the form of contact resistance or an incorrectly located RPM sensor.

LB8




IF Diagnostic Trouble Code (DTC) 2-1-4 Is Logged (cars With Manual Gearboxes)
- Delete the DTC
- Check the RPM sensor connector for contact resistance in accordance with NA6. NA. Checking the Wiring
- Check that the RPM sensor is correctly located in its bracket.
- Run the engine at over 1500 rpm for 5 minutes.

If the DTC recurs
^ Connect the test box LB6.

If the DTC does not recur
^ The fault took the form of contact resistance or an incorrectly located RPM sensor. Clean the RPM sensor connector in accordance with NA7. NA. Checking the Wiring