Description

1991 Nissan 180SX Service Manual – SR20DET Supplement

You bought a 180SX with the SR20DET and now you’re staring at a wiring mess or a tick from the valvetrain. Generic aftermarket manuals don’t have the ECCS pinouts or the compression spec at 11.0 kg/cm² at 300 rpm. This is why you need the factory Nissan 180SX 1991 Service Manual. It’s a 101-page supplement, not a full vehicle manual – but for the SR20DET, it’s the only source you should trust. I’ve seen too many guys chase ghost codes because they used a third-party book that swapped pin colors. Don’t be that guy.

SR20DET Mechanical Specs – The Numbers You Need

The OCR excerpt from page 1 lists the core engine specs. Displacement: 1998 cc. Compression ratio 8.5:1 with a compression pressure of 11.0 kg/cm² at 300 rpm. Idle speed is 800 rpm for both M/T and A/T, with ignition timing at 15° BTDC at idle. Valve clearances are listed as 0 mm – automatic adjustment via hydraulic lifters. These are factory targets, not suggestions. If your gauge reads different, you know where to start looking.

Fuel consumption rate is 200 g/PS·h at 2000 rpm, and idle CO should be under 0.1%, HC under 50 ppm. The manual also specifies the recommended engine oil: Nissan genuine SG class 7.5W-30 (Turbo X). Oil pan capacity is 3.7 liters at H level; filter capacity is approximately 0.3 liters. These numbers match what I’d expect from a Nissan turbo four from that era. Page 1 is where you’ll find the engine spec table – it’s the bedrock of any diagnosis.

ECCS System Diagram: Tracing the Wiring

The SR20DET uses Nissan’s ECCS (Electronic Concentrated Control System). The manual includes a system diagram showing the control unit, ignition switch, battery, power transistor, crank angle sensor, air cleaner, airflow meter, boost pressure sensor, wastegate solenoid, and the turbocharger itself. Signals flow from the crankshaft position sensor, throttle position sensor, oxygen sensor, knock sensor, and water temperature sensor into the ECCS control unit. Outputs include ignition timing, fuel injection, idle speed control (AAC valve), and boost control. If you’re chasing a no-start or a misfire, trace each wire against this diagram. Aftermarket wiring diagrams often combine multiple years – this one is specific to the 1991 180SX chassis code E-RPS13 and E-KRPS13.

For reference, check the Automotive Industry Overview to understand how Nissan engineered the ECCS across models, but for hands-on work, stick to the OEM document.

Does This Manual Cover the Fuel System?

It covers the fuel injection system as part of ECCS, but it does not cover the fuel tank, lines, or pump in detail – those are in the main chassis manual. What you get here is the injection control: injectors, fuel pump relay control, and the air/fuel ratio feedback via the O₂ sensor. The manual shows the idle CO adjustment procedure and target values. If you need the full fuel system layout, you’ll need the main service manual.

101 Pages – What’s in Section B1

This supplement is section B1 – SR20DET mechanical. It’s 101 pages total, but that’s not the whole car. The content includes engine specs, ECCS system diagram, component locations, and likely removal/installation steps (though the detailed procedures may be in the main binder). The Japanese text is dense, but the tables and schematics are universal. If you can read a multimeter and a torque wrench, you’ll get what you need. For other Nissan models, consider Nissan Xterra 2005 Service Manual – OEM Factory Spec or Nissan 60 1967 Service Manual – Original Factory Bulletin for older gear. Nissan L60, L60-U, KL60-U 1968 Service Manual – Factory Specs is also available if you work on vintage stuff.

Source Authenticity: Nissan OEM vs Aftermarket

This is a scanned copy of an original Nissan factory publication, not a third-party recompilation. The scan quality is good – you can read the tables and diagram labels. Aftermarket manuals often omit the ECCS pin assignments or modify torque specs to fit generic patterns. I’ve seen aftermarket books list the wrong compression ratio. Don’t risk it. This document was published by Nissan in January 1991, part number A008011. It’s the real deal.

Page 1 is the only page I’ve cited here because that’s where the critical spec table lives. If you need the charge pressure or idle specs, that’s where to look. The rest of the 101 pages contain diagrams and component data you’d be hard-pressed to find anywhere else.

FAQ – Common Questions from Shop Guys

Does this manual cover the entire 1991 Nissan 180SX?

No. It is a supplement for the SR20DET engine and ECCS system only. You need the main chassis service manual for suspension, brakes, body, and interior.

What torque values are listed?

The excerpt shows compression pressure (11.0 kg/cm²) but does not provide assembly torque specs like head bolts or main caps. Those would be in the main SR20DET engine section of the full manual (not included here). However, the manual does contain oil capacity data and spark plug type recommendations.

Is the text in English or Japanese?

The scanned pages are primarily Japanese text with some English labels on diagrams and tables. If you can’t read Japanese, you’ll rely on the schematics and numbers – which for a mechanic is often enough. The spec table uses universally understood symbols and units.

Will this work for a CA18DET 180SX?

No. This is specifically for the SR20DET (engine code SR20DET). The CA18DET is a different engine family with different wiring, compression, and boost control. You need the manual for your specific engine variant.

If you’re serious about keeping your SR20DET 180SX running right, you need the data straight from Nissan. Automotive Industry Overview can give you background on turbocharged four-cylinders, but for the actual repair, nothing beats the factory book. Access the Factory Manual and get the specs that matter.