3.Engine Misfires or Stalls, and CAN Be Restarted
- engine lacks power or surges- heavy combustion knock is experienced
IMPORTANT! Diagnosis and repair instructions for each symptom are listed in the order to be performed, and all checks listed must be performed regardless of any fault found.
During the fault tracing/repair sequence, ensure that all connectors and components are: - free from corrosion
- fit correctly and are not loose (replace connector if suspect)
- connectors are not crimped onto the insulation, instead of the wire
3.1 IDLE ADJUSTMENT
Check ignition timing, CO-content and basic idle speed (refer to Service Manual TP 30427/1) Seal CO-adjustment (if adjustment performed)
3.2 IGNITION ADVANCE
Check "centrifugal" advance.
Disconnect vacuum hose from control unit.
Run engine at 2,500 rpm and check that ignition advance is 16-24~ BTDC.
If incorrect, replace control unit.
Check vacuum advance.
Run engine at 1,500 rpm.
Record ignition advance. Reconnect hose and check that advance alters.
If not, check for vacuum at control unit (check suction at hose).
If vacuum is present, but no advance, replace control unit.
3.3 CONNECTING GUIDE SLEEVES
Remove connector from the ignition distributor and control unit. Check that there are guide sleeves, P/N 1324909-9, on all three pins in the distributor connector and on pins 3, 5 and 9 in the control unit connector. Clean pins of all grease, oxidation or plastic contamination.
NOTE! The distributor connector for MY 1984 is a Bosch type, and does not require any guide sleeves.
Install guide sleeves with tool 9995268-1, if sleeves are missing.
Fill the tool with Volvo grease (electrical non-corrosive grease), P/N 8708073-5, and place the sleeve in the tool.
Press the sleeve onto the male pin until 2 mm (1/16" - 1/8") of the tip of the pin is visable.
NOTE! Only install guide sleeves on pins 3, 5 and 9 in the control unit
3.4 Wiring Harness
Because of lower current flow and difficulty in verifying electrical continuity, replacement of the harness is the preferred repair method, as the female connectors could be damaged or lose tension. The wiring harness between distributor and control unit part numbers are:
MY 1983 P/N 1332643-4 MY 1984 P/N 1346259-3
Apply grease (electrical non-corrosive grease) P/N 8708073-5, on the connectors for distributor and control unit.
NOTE! Do not use grease on the 1984 distributor connector.
Connect wiring harness to control unit and distributor.
IMPORTANT! Do not twist connectors when installing. Make sure connectors are correctly aligned with the component when fitting.
3.5 Ignition Coil
Check terminals, make sure connectors at terminals 1 and 15 of the ignition coil are clean and tight.
Check that the high tension cable between coil and distributor is properly installed.
3.6 Multipin Connector
Check multi pin connector at firewall for corrosion and loose terminals. Clean connectors, ensure connector/pin continuity.
3.7 Ground Connections, Fuel System
Ensure that the ground connections at the inlet manifold are clean, tightened and not damaged.
3.8 Fuse, Fuel System
Check 25-AMP blade fuse in engine compartment.
Clean fuse and fuse holder and apply grease*, P/N 8708073-5, before reinstalling fuse, ensure proper tension of connectors.
* (Electrical Non-Corrosive Grease)
3.9 Fuse Box
Check for a firm fit of connectors and fuses at position 5, 11, 12 and 13 in fuse box.
3.10 Fuel System Relays
Relays are mounted inside the vehicle, on right side of firewall.
Check fuel pump and system relays for discolored pins or connectors. If necessary, replace the plug, (female connector) and relays.
3.11 Main Fuel Pump Wiring
Wiring located under the rear seat.
Check for good connection and that the screw is tightened.
Check the fit of the power supply connector.
Make sure that both wires are not pinched or damaged in any way.
3.12 MAIN AND PRE-PUMP FUNCTION
Remove panel on right side under dashboard. Disconnect the 3-pin connector.
Connect a jumper wire between the blue/red and red/yellow wires in connector.
Switch on the ignition, pumps should start. Main fuel pump operation can be sensed by feeling the fuel line pulsations by hand. Tank pump operation can be heard by removing fuel tank cap and listening at filler tube.
Check fuel pump capacity.
Turn off ignition.
Disconnect return line at the pressure regulator. Install hose, P/N 1266500-6 length 1000 mm (40") at the pressure regulator and hold the open end above a measuring glass.
Turn on ignition for 30 seconds.
Min. volume of fuel should be 1.0 L/ 30 sec. (approx. 1 US qt/30 sec)
Too low fuel quantity could be caused by a restricted fuel line, fuel filter or too low capacity from fuel pump or prepump.
Reconnect the return line at the pressure regulator.
PREPUMP CHECK
Check for voltage at tank pump and ground wire in the trunk.
Voltage should be at least 11.5V
Make sure that ground screw washer contacts body.
NOTE! Wires are routed differently, depending on model year.
Late type is shown in adjacent illustration.
Check tank pump current.
Connect an ammeter in series with the connector in the trunk.
Current consumption should be 1-2 amps.
If current consumption is too high, this could indicate that the pump/filter is blocked or that the pump has seized.
Turn off ignition.
Connect pressure gauge 9995230-1
Pinch fuel line between tank pump and main fuel pump. Use pliers 9992901-0
Connect pressure gauge 5230 with a "Tpiece and hose (P/N 1312257-7*), T-piece (P/N 367844-8) and hose clips.
Remove pliers 2901.
* Available only in bulk quantities.
Check operating pressure of pump.
Turn on ignition to start pump.
Pressure should be at least 13.5 kPa (1.9 psi).
Turn off ignition.
Check max pressure of pump.
Pinch fuel line next to main fuel pump. Use pliers 2901.
Disconnect one wire from pump so that it cannot operate.
Turn ON ignition.
Pressure should be 28-45 Kpa (4.0 - 6.4 psi).
Remove pliers 2901. Reconnect wire to main fuel pump.
Fuel pressure too low.
Remove fuel gauge sender and check hose between prepump and fuel gauge sender for damage.
If no damage can be found, replace prepump.
Reinstall fuel gauge sender and repeat pressure check.
Remove pressure gauge and hoses.
Pinch fuel line with pliers 2901 before removing gauge.
Reconnect 3- pin connector under dashboard and install panel.