Rover's Vikingship Testing the EFi System Rover's Vikingship

To diagnose a problem is to find a possible cause. A good place to start is with the plugs. Remove the plugs and keep them in cylinder order. Now use the chart as shown on the maintenance page.

Plug coloursCondition
Left bankRight bank 
GreyGreyIndicates a possible fault in ignition system, plug leads condition or routing, timing, centrifugal or vacuum advance.
WhiteWhiteCould be air leaking into inlet system.
suspect Air Valve or one of the many vacuum connections.
Less likely but possible,the electrics or the Air flow meter.
BlackBlackIf air filter and hose connections are good it could be the fuel regulator,thermotime switch or coolant temp. sensor. Signalling engine is cold when it is already hot. Faulty air flow meter is also a possibility
Black
Grey
Grey
Black
Over fuelling on one bank. Most certainly an electrical fault. Poor connection or chafing of the wires. Or...problems with your ECU

The Rover V-8 EFI system is very sensible for leaking vacuum connections which can result in a bad idling and/or a rough running engine. Therefore carefully inspect all the vacuum pipes for leakage and check the conditions of the clamps!. On the SD1 most piping is at least 13 years old by now so the rubber can be hardened or become porous.

An indication for a vacuum leak can be noticed because the engine is running rough on idling and low rpm. The rough running then slowly disappears with increasing rpm. This can be explained because at idle and low rpm the throttle valve is almost closed. This gives a high vacuum in the plenum chamber and thus a high vacuum in the vacuum piping. So a lot of outside air is sucked in directly instead of going through the air flow meter, as a result the air/fuel mixture is too lean resulting in a poor running engine, and yes..those white noses on your plugs. With wider throttle openings the vacuum becomes less and thus less air is leaking in.

A simple test if you have a rough running engine at low rpm is to disconnect the filter and manually (with a screwdriver for instance) open the flap of the airflow meter a bit with the engine idling. This way you make the EFI system injecting more fuel. If the engine starts to run smooth there is almost certainly a leakage in your vacuum piping.

Excessive fuel consumption and black smoke can be caused by a perforated diaphragm from the fuel pressure regulator. To check this remove the vacuum pipe. If there is fuel coming out of the regulator's vacuum connection, the diaphragm is at fault and the regulator should be replaced.

If the problem wasn't in the hose connections or in the ignition then the following tests can help you locating the fault in your EFI system.

Test 1 Voltage supply

Test no. 1  (8,4 kB)

ECU connected
Ignition off
Voltmeter connected between pin 30/51 of the main relay and earth.

The reading should be 11 to 12.5 Volts

If below 11 Volts or 0 Volts check:

  • State of the battery
  • Earth connections
  • Positive connections to main relay (Brown wire (N))
If OK continue with Test 2

Test 2 Voltage supply to ECU

Test no. 2  (8,5 kB)

ECU DISconnected
Ignition OFF
Voltmeter connected between terminal 10 of the multiplug (Not the ECU itself!) and earth.

The reading should be 0 Volts
If above 0 Volts renew the main relay

Turn ignition ON
Main relay can be heard by a click and voltmeter should read 11 to 12.5 Volts If below 11 Volts or 0 Volts check:

  • All the white wire connections (W) to the relays and steering module
  • Earth connections at terminal 86 and both relays
  • Good connection of brown&orange wire (NO) at main relay terminal 87
  • Good connection of blue&yellow wire (UY) at main relay terminal 87 and ECU pin 10.
If still below 11 Volts subsitute the steering module and the main relay.

If OK continue with Test 3

Test 3 Voltage supply to Fuel pump

Test no. 3  (9,6 kB)

ECU DISconnected
Ignition ON
Voltmeter connected between terminal 20 of the multiplug (Not the ECU itself) and earth.
Air flow meter flap closed the meter should read zero Volts

Manually open the flap of the meter.
Listen for the fuel pump and relay operation.
Voltmeter should read 11 to 12,5 Volts

If below 11 Volts check:

  • All wiring connections as shown in this diagram.
If still below 11 Volts
Substitute the steering module

If the voltmeter reads correctly but the relay or pump don't operate
Subsitute steering module and then pump relay.

If pump still isn't operating
Suspect a faulty fuel pump.

If OK continue with Test 4

Test 4 cranking Voltage

Test no. 4  (9,0 kB)

ECU DISconnected
Voltmeter connected between ECU terminal 4 and earth.

Ignition ON and cranking
The reading should be 8 to 12 Volts

If no reading but the starter motor operates check:

  • White&red (WR) wiring
  • connections to ECU pin 4 via the steering module and the wiring loom multiplug.
If below 8 Volts check:
  • Battery and starter motor
If no readings and the starter motor does not operate,check:
  • Black & orange (BO) wiring, connections and starter circuit
If OK continue with Test 5A (with separate ignition amplifier)
or continue with Test 5B (with integral ignition amplifier)

Test 5A Voltage speed signal circuit
fuel shut off relay and vacuum switch

Test no. 5A  (6,4 kB)

ECU DISconnected
Connect a jump lead between the negative coil terminal and the white/blue (WB) connector adjacent to the coil.
Voltmeter connected between ECU multiplug terminal 1 and earth.

Ignition ON
Listen for operation of fuel shut-off relay

If relay does not operate check:

  • White wiring (W) and connections
  • earth connection 86 from relay
  • the vacuum switch and the connection hose, subsitute if necessary
CRANK the engine
Voltage should fluctuate between 6 and 9 Volts

If higher than 9 Volts or lower than 6 than check:

  • electronic ignition system
If OK continue with Test 6

Test 5B Voltage speed signal circuit
fuel shut off relay and vacuum switch

Test no. 5B  (7,4 kB)

ECU DISconnected
Disconnect the connector from the resistor at the negative coil terminal and connect a Voltmeter between the resistor and the connector. (see diagram)

Ignition ON
Listen for operation of fuel shut-off relay

If relay does not operate check:

  • White wiring (W) and connections
  • earth connection 86 from relay
  • the vacuum switch and the connection hose, subsitute if necessary
CRANK the engine
Voltage should fluctuate between 6 and 9 Volts

If higher than 9 Volts or lower than 6 than check:

  • electronic ignition system
If OK remove voltmeter and reconnect the connector, continue with Test 6

Test 6 Voltage of airflow resistor

Test no. 6  (7,3 kB)

ECU connected
Disconnect the multiplug, remove the multiplug cover and reconnect the multiplug.
Ignition ON
Voltmeter connected between pins 8 and 9 with the multiplug connected to the ECU

Air flow meter flap closed. The voltmeter should read 1.55 +/- 0.1 Volts

If reading is incorrect

  • peel back the rubber covering at the flow meter and connect voltmeter to terminals 8 and 9
  • Measure readings again
If reading is still incorrect the air flow meter is faulty. Open the top of the flow meter and check the potentiometer. It could be that corrosion damaged the tracks of the potentiometer or the pick-up points are corroded.

If OK leave the ECU connections exposed and continue with Test 7

Test 7 Voltage of airflow potentiometer

Test no. 7  (7,6 kB)

ECU connected
Disconnect the multiplug, remove the multiplug cover and reconnect the multiplug.
Ignition ON
Voltmeter connected between pins 6 and 9 with the multiplug connected to the ECU

Voltmeter should read 4.3 +/- 0.2 Volt.

If Voltmeter reads 0 check:

  • All wiring and connections seen in the diagram above
Voltmeter connected between pins 6 and 7
Voltmeter should read 3.7 +/- 0.1 Volt

If voltmeter reads lower check:

  • The wiring for high resistance (corrosion)
With the voltmeter connected between pins 6 and 7 slowly open the air flap.

The Voltage should gradually decrease to 1.6 +/- 0.1 Volts

If the results are not within the specifications the potentiometer is at fault. Take the cover of the air flow meter and check the potentiometer for corrosion, etc.

If OK refit the ECU multiplug cover and continue with Test 8

Test 8 Resistance of airflow potentiometer

Test no. 8  (7,5 kB)

ECU multiplug DISconnected
Ignition OFF
Air flow meter flap closed.
Ohmmeter connected between pins 6/8, 6/9 and 8/9

PinsOhms
6 and 8360 +/- 10 Ohms
6 and 9560 +/- 10 Ohms
6 and 9200 +/- 10 Ohms
If Ohmmeter readings are incorrect:
  • Peel back rubber boot covering at airflow meter and repeat the test at the air flow plug and then at the air flow meter socket
If the readings are still incorrect:
  • the potentiometer is at fault. Take the cover of the air flow meter and check the potentiometer for corrosion, etc.

If OK refit the ECU multiplug cover and continue with Test 9

SD1 injection....The basics

SD1 injection....The Airflow meter

SD1 injection....Testing the EFI page no. 2



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