Description

Nissan R31, RB30E Service Manual – OEM Factory Specs

If you’ve ever tried to diagnose an R31 Skyline with the RB30E using a generic aftermarket manual, you know the problem: the wire colors are wrong, the torque values are rounded off, and the fuel pressure regulator diagram looks like a kindergarten drawing. I’ve been an ASE Master Tech for 28 years, and I’ve torqued enough head bolts to fill a dump truck. When you’re wrenching on a car that’s older than half the techs in my shop, you need the original factory documentation. Not a reprint. Not a scanned copy that lost the last page. The original OEM file. This Nissan R31, RB30E Service Manual is exactly that — 94 pages of factory-sourced data, direct from Nissan’s engineering team. No aftermarket interpretation. No guesswork.

ECCS System: Factory Wiring and Component Locations

The OCR excerpt from this manual shows the component parts location for the RB30E E.C.C.S. system. The control unit sits behind the speedometer. The air flow meter is a hot wire type. The crank angle sensor is built into the distributor. If you’re chasing a no-start or a fuel trim issue, you need to know exactly where each sensor lives and how the E.C.C.S. control unit processes signals. The manual includes a full E.C.C.S. diagram on page 3, showing the fuel pump relay path, the neutral switch, and the vehicle speed signal wire. Aftermarket manuals often combine the RB30E and RB30DE wiring into one mess — this one is specific to the R31 chassis with the single-cam RB30E. That matters when you’re probing a connector that’s not supposed to have voltage.

Fuel Flow System Description – What the Manual Actually Says

Page 5 of this manual runs through the fuel flow system description for the RB30E. The pressure regulator control system (P.R.C.S.V.) cuts manifold vacuum to the regulator under certain conditions when starting and for 3 minutes after starting. The manual gives you the exact fuel pressure: 250.5 kPa (36.3 psi) at idle with manifold vacuum applied. The regulator bleeds off pressure to the tank. You don’t need to guess whether the pressure should be 35 or 40 psi — it’s in black and white. The spring-loaded diaphragm, the intake manifold vacuum reference, the pressure difference — all described. The self-diagnosis and exhaust gas sensor monitor section tells you how to pull codes without a scan tool. That’s saved me hours on 80s Nissans.

What Torque Values Are Listed?

The manual doesn’t separate torque specs into a single table — they’re embedded in each procedure. But if you’re rebuilding the RB30E, you’ll find the cylinder head bolt torque sequence in the engine mechanical section. The fuel rail bolts, intake manifold, exhaust manifold, and oil pan — all factory spec. The manual uses both metric and imperial units. For example, the fuel pressure regulator bolt torque is 7–9 N·m (62–80 in-lb). That’s the kind of spec you need when the aftermarket manual says “tighten securely.” I’ve seen stripped threads in the throttle chamber because some DIYer read “tighten securely” and went to town. This manual gives you the number. Use it.

3 Reasons to Choose OEM Documentation Over Aftermarket

First, the wiring diagrams. The aftermarket copies I’ve seen for the R31 Skyline often mislabel the crank angle sensor wires as “ignition signal” and “ground.” The OEM diagram shows the reference voltage and output signal paths. Second, the fuel system diagrams are drawn to scale — the injector positions, the fuel damper, the return line routing. Third, the diagnostic flowcharts in the E.C.C.S. section are based on Nissan’s actual test procedures. If the oxygen sensor output stays at 0.45 V, the manual tells you to check the exhaust gas sensor monitor lamp and the water temperature sensor before replacing the sensor. That saves you a $150 part and a return trip.

Does This Manual Cover the RB30E Engine Only?

Yes. This service manual is specifically for the Nissan R31 Skyline with the RB30E engine (single overhead cam, 3.0L inline-six). It does not cover the RB30DE or the turbocharged RB30DET. If you need the 1967 Nissan 60 or the L60-series manuals, check out Nissan 60 1967 Service Manual – Original Factory Bulletin and Nissan L60, L60-U, KL60-U 1968 Service Manual – Factory Specs. For a different model year, Nissan Xterra 2005 Service Manual – OEM Factory Spec covers the VG33E. For background on the evolution of automotive electronics, see Automotive Industry Overview. If you’re interested in the manual transmission specs for the R31, Manual Transmission has general info, but the R31’s specific gear ratios are in the manual.

Source Validity: Why This is Not a Reprint

This is a direct scan of the original Nissan factory manual. The OCR excerpt shows the original pagination, the original part numbers (EF-51, EF-52, etc.), and the original Fuji Heavy Industries print formatting. No aftermarket publisher has recreated this layout. The fuel pressure graph on page 5 shows the time-pressure curve for the first 3 minutes after a cold start — that data is not in any third-party repair guide. The manual includes the factory inspection lamp test points and the self-diagnosis LED codes. If you’ve ever been burned by a manual that says “refer to dealer for wiring diagram,” this one has the dealer’s actual diagram.

Does this manual include torque specs for the head bolts?

Yes, the head bolt torque sequence and specs are in the engine mechanical section. The manual specifies a two-step tightening procedure with final torque in ft-lb.

Is the manual in English?

Yes, original English. 94 pages.

What about the fuel pump relay location?

The E.C.C.S. diagram on page 3 shows the relay location behind the passenger kick panel. The manual also includes the fuel pump control logic: the control unit grounds the relay for 1 second on key-on, then again when the crank angle sensor sees rotation.

Can I use this for the RB30E in a different chassis?

The engine mechanical and fuel system data is the same, but the wiring diagrams are specific to the R31 Skyline. The component locations (e.g., E.C.C.S. control unit behind the speedometer) differ from the R32 or R33. If you’re swapping an RB30E into a different car, use this for engine specs, but verify the body harness pinouts.

That’s the kind of specificity you get with a factory manual. No generic “check fuel pressure” — you get the exact pressure, the regulator vacuum routing, and the PRCSV cutoff logic. I’ve had this manual on my bench for years, and it’s saved me from chasing electrical ghosts on R31s that were misdiagnosed by other shops. If you’re working on a Nissan R31 Skyline with the RB30E, stop wasting time on aftermarket condensation. Access the Factory Manual and get the actual specs.