MFI #18 Injector Pulses Absent

TL. MFI#18

MFI#18 Injector pulses absent

Fault Message Conditions:




If voltage has not been below 9 V. for a certain amount of time, approx. 250 ms, the fault message is logged.

A fault message is not logged if fuel shut-off requirements are met - engine speed has been over 2200 rpm and then not dropped below 1100 rpm and the idle switch is on.

Causes of fault:

Break or grounding in the wiring between MFI#18 and the injectors.

No power supply to the injectors.

Fault symptoms:

The engine will not start.

If the fault is intermittent the engine will stop or engine speed will drop.

TL1

Volvo ST, Test Box




-Disconnect the ST.

-Connect the test box to MFI and check the GND points.

-Continue with Checking the power supply TL2.

TL2

Checking The Power Supply

Connect the control module to the test box.

-Install the fuse.




-Ignition on.

Connect a voltmeter between MFI#1 8 and MFI#1 7 (Power GND). The voltmeter should read battery voltage.

If this value is OK

-heck the control of #18 TL3.

If the reading Is incorrect

-Check wiring between MFI LH #18 and injectors for breaks as in NA2. Checking the Wiring

-Check wiring between injectors and main relay terminal 1 and wire between main relay terminal 3 and fuse from battery (in engine compartment (-90) or no.6 (91-) for breaks or loose contacts as in NA2 and NA5. Checking the Wiring

TL3

Checking The Control Of #18

Connect a voltmeter between MFI#18 and MFI#35 (voltage).




-Operate the starter motor.

The voltmeter should read under 1 V.

If this value is OK

Intermittent fault.

-Check the connections between MFI#18 and the injectors for loose contacts and intermittent grounding in accordance with NA5 and NA3Checking the Wiring.

-Check the wiring between MFI#18 and the suppressor relay via the injectors for loose contacts and intermittent grounding in accordance with NA5 and NA3.Checking the Wiring

If the reading Is incorrect

-Try using a new control module.