RB30 Facts, Figures and Helpful Hints

[mudnut]

The RB30 engine uses different engine control and electrical components than the more popular TB42.

Sometimes, I have found it difficult to locate items on and data for my vehicle. Feel free to post any information and/or helpful hints or experiences regarding the maintenance and repair of the RB30.

Fuel Return Solenoid.

If the engine wants to flood at Idle, maybe the fuel return solenoid isn't functioning properly.

There is an Engine Revolution Sensor Unit which is fixed to the metal end under the Drivers Side of the dash. It receives an RPM signal from the coil through a resistor which is cable tied or taped to the top radiator hose. The Engine Revolution Unit supplies a signal to the fuel return solenoid.

The circuit is on page 12-15 of the Haynes manual.
With Ignition off. Unclip the return fuel solenoid connector and check the resistance of the solenoid with a multimeter. It should have a resistance of between 20 to 25 ohms.

If you intend to check the operation of the circuit live, dig out the rubber grommets which seal the wires at the connector. Insert the meter probes and set it to volts.

With the engine running, the voltage readings to the solenoid are: at idle 12 to 14 volts and zero volts above 1450 rpm, (you should be able to hear it click in and out).

I used some some silicon to reseal the wires, making sure no silicon is between the wires, so there is no chance of current tracking between the two.

The Fuel Return solenoid is situated under the top radiator hose.


Added info below from Dom14.

RB30 Facts, Figures and Helpful Hints - Hyperlinks to specific areas of the thread.


Fuel Return Solenoid

Fuel Pump Control Unit(FPCU)

Engine can't achieve high revs

Engine coolant drain plug

Speedo Problems and Adjustment

Ignition Auto Advance Vacuum Diaphragm (Poor Performance and Fuel Economy ).

Testing for a blown head gasket

Air Intake Pre-heat assembly fitted to a stock RB30S

Reasons for Backfiring

Heater core blockage cleaning method on a GQ Patrol

instrument panel circuit for an RB30S

RB30 Patrol(or any vehicle) Universal Joint(s) Replacement

RB30 Vacuum line diagram and related components

RB30 Patrol Coolant flow diagram(s)

RB30-TB42 Nikki carby tuning procedure(temporary)

Carburetor lean/rich diagnostics

A useful modification after snorkel installation

Fan Clutch test

[mudnut]

Fuel Pump Control Unit

This is situated below the fuses behind the drivers kick panel. This unit switches the fuel pump on and off. It also provides a timing circuit to prime fuel to the carby for a few seconds when the ignition is turned on.

The fuel pump is allowed to operate via an oil pressure switch on the engine. (Green wire)

This is to protect the engine from loss of oil pressure.

The fuel control unit has the timing circuit to allow the fuel pump to run, until sufficient oil pressure is reached.

The fuel control unit has Brown, White/red, Black, Green/red, Green and Light Green wires at the connector.

[mudnut]

Engine can't achieve high revs.

If the engine has trouble obtaining high revs, the second stage carby butterfly may be sticking or is stuck shut. It is possible to operate the second stage by hand, while the carby is on the engine, (It is a lot easier with the air filter housing removed). In the past, I have had to take the carby off and the butterfly out. I then used some fine wet'n' dry sand paper to smoothe the carby bore and the butterfly edges. When refitting the butterfly, take care to seat it in the bore properly. Test that it moves freely and does not try to stick in the shut position. It took me quite a few adjustments of the butterfly to get it operating correctly.

[mudnut]

Engine coolant drain plug.

When changing out the engine coolant you need to open the drain plug in the engine block. It is situated under the exhaust manifold towards the rear of the block. (The hex head of the plug on my engine is 22mm.) The plug uses a copper washer to maintain a good seal.

[NP99]

Engine coolant drain plug.

When changing out the engine coolant you need to open the drain plug in the engine block. It is situated under the exhaust manifold towards the rear of the block. (The hex head of the plug on my engine is 22mm.) The plug uses a copper washer to maintain a good seal.

I wonder how many radiator places do that? Good info mate.

[mudnut]

I can't take the credit for knowing where the drain plug is. George (Alitis) posted it a while back.

[mudnut]

Speedo Problems and Adjustment.

Here are some Links to threads dealing with speedos:

http://www.nissanpatrol.com.au/forum...peed-sometimes

http://www.nissanpatrol.com.au/forum...=adjust+speedo

Some forum members have had success at getting their speedos, odometers and trip meters to work by thumping the dash. The cause of a problem may occasionally be found (or sometimes fixed if you are lucky), by taking the the dash surround off and tapping the connections and casing with the handle of a screwdriver.


The first picture is of a test lead I made, using the stainless steel strip from a windscreen wiper. I cut them to length, bent them to shape and soldered them to a piece of twin core flex cable. These U shaped ends can be pushed into the back of the gauge cluster connectors. The cluster can be refitted so the car can be driven and on road readings can be easily taken. The other ends have been stripped, soldered and mounted with a insulation between them so the multimeter probes push in firmly.

The second picture shows the hole drilled in the top of the cluster, for access to the speedo adjustment potentiometer, as GQ TANK posted in the above mentioned thread. I use a 9/32 drill bit (by hand) so that I can fit the old style caps used on power point face plates.

[mudnut]

Auto Advance Diaphragm (Poor Performance and Fuel Economy ).

One possible cause of poor economy and performance may be the Auto Advance Diaphragm. It is situated on the front of the distributor. It can be checked by removing the vacuum hose while the engine is running. The engine revs should drop and then pick up, immediately the hose is refitted.

Another way to test the diaphragm is by using a hand operated vacuum pump which can be bought at an auto spares shop or off EBay. (I converted an old bike pump to work in reverse. But use it gently or the diaphragm may split).

I found the Diaphragm was not holding vacuum so I had to send it away to get reconditioned, via BURSONS.

The pictures below show the diaphragm at rest and under vacuum pressure. See how the arm retracts into the housing.

Because I had to wait for the diaphragm to be returned, I used this Mitsubishi Diaphragm from the wreckers. I adapted it to fit by filing the arm to shape then cutting it. I manufactured a new end from a scrap of mild steel. I used clamps as heat sinks to protect the diaphragm rubber when I brazed the new end on.

[mudnut]

Equipment Location.

The relays for the Air Conditioner, Horn, Auto Choke, Power Windows, Ignition, Accessories and Heater are located under the steel plate next to the main battery.

The Rear Wiper Amplifier module is also mounted under this plate. It is clipped to the inner guard.

The picture is upside down so you can read the tags.

[mudnut]

Choke Break Diaphragm.

If the engine is flooding itself a few minutes after a cold start up, the Choke Break Diaphragm might be split or holed. Its job is to pull the auto choke off. Damage to the Choke Break Diaphragm and also the Auto Advance Diaphragm can be caused by the engine backfiring. The Choke Break Diaphragm is situated at the rear top of the carby, on the passenger side.