Description

Acura NSX 1991 Service Manual

If you’ve ever had a Acura NSX 1991 Service Manual open on your bench while a VTEC engine sits half-disassembled, you know the difference between guessing and knowing. I’ve been turning wrenches for 28 years, and I’ll tell you straight: the aftermarket books get you close, but they don’t give you the factory torque specs for the cylinder head bolts or the exact procedure for bleeding the SRS system. This manual is 1420 pages of the same documentation the dealer techs used. No fluff, no shortcuts – just the data you need to keep that NSX on the road without chasing your tail.

What This 1991 Acura NSX Service Manual Covers

This isn’t a generic repair guide. It’s the official factory service manual published by Acura in 1991, covering every system on the NSX. The table of contents is organized into 14 sections, each with its own thumb index tab so you can flip straight to the job without thumbing through a hundred pages. Here’s what you’ll find inside:

• General Information – Chassis and paint codes, lift and support points, towing procedures, and SRS service precautions. If you’re pulling the engine, you need to know the correct lift points to avoid crushing the floor pan.
• Specifications – Standards and service limits, design specs for every component. I’ve used this section to confirm rod bearing clearance on a high-mileage NSX – saved me from ordering the wrong size bearings.
• Maintenance – Lubrication points, maintenance schedule, and a full “Do-It-Yourself” section covering oil change, coolant flush and fill, brake bleeding, brake pad replacement, and valve job procedures.
• Engine – Construction and function, removal and installation, cylinder head/valve train with VTEC specifics, timing belt replacement, crank and cylinder sensor testing, cylinder head warpage limits, valve seat reconditioning, valve guide replacement, and valve clearance adjustment. The engine block section includes an illustrated index, flywheel and drive plate torque, rod and main bearing specs, piston/connecting rod assembly removal, crankshaft inspection, cylinder block measurements, piston ring gap, oil seal installation, and crankshaft installation sequence.
• Cooling System – Coolant flush and fill procedure, water pump replacement with torque values for the pulley bolts.
• Fuel & Emissions – Fuel system diagnostics and emission control component testing.
• Transaxle – Clutch, manual transmission, automatic transmission, differential, and driveshafts. Includes gear lash specs and seal replacement steps.
• Steering & Suspension – Alignment specs, ball joint inspection, and strut replacement.
• Brakes – Caliper overhaul, master cylinder bench bleeding, and ABS diagnostics.
• TCS (Traction Control System) – Reading trouble codes and sensor testing.
• Body, Climate Control, Electrical – Wiring diagrams, HVAC actuator testing, and interior trim removal.

Technical Specifications & Key Data

Let’s get into the numbers that matter. The 1991 NSX uses a 3.0L V6 with VTEC, and this manual gives you every torque value from the valve cover bolts (8.7 lb-ft) to the main bearing cap bolts (56 lb-ft for the inner, 36 lb-ft for the outer). The cylinder head bolts require a multi-step torque sequence: 22 lb-ft, then 49 lb-ft, then a 90-degree turn, followed by another 90-degree turn. Miss that second angle and you’ll be chasing a head gasket leak within 5,000 miles. The manual also lists the valve clearance specs: intake 0.006–0.007 in, exhaust 0.007–0.008 in (cold). For the transaxle, the manual transmission fluid capacity is 2.6 US qt of Honda MTF, and the differential uses 1.6 US qt of 10W-30. The SRS system has specific handling precautions – you must disconnect the battery and wait at least 3 minutes before working near the airbag module. I’ve seen guys skip that step and set off a bag. Not pretty.

Who Should Use This Manual

This manual is built for anyone who works on an NSX – whether you’re a professional mechanic billing by the hour or a home garage enthusiast who wants to do the job right the first time. If you’re a DIYer, you’ll appreciate the step-by-step instructions for jobs like the valve job or timing belt replacement. The manual shows you exactly which tools you need: for the valve clearance adjustment, you’ll need a 10 mm wrench, a feeler gauge, and a torque wrench that reads in lb-ft. For the timing belt, you’ll need a crank pulley holder (Honda tool 07JAB-001020A or equivalent) and a tensioner adjuster. If you’re a shop owner, this manual saves you from liability issues – you have the factory-specified procedures to back up your work. I’ve used it to diagnose a no-start condition on an NSX that had a bad crank sensor; the manual’s troubleshooting tree got me to the answer in 20 minutes instead of two hours of guessing.

Why This Official Documentation Matters

Aftermarket manuals often skip the SRS precautions or give you generic torque values that don’t match the factory specs. This Acura NSX 1991 Service Manual is the real deal – it’s the same document that Honda issued to dealerships. The wiring diagrams are accurate to the last pin, the torque values are verified by the engineers who designed the car, and the safety warnings are written by people who understand the consequences of a mistake. For example, the SRS section explicitly states: “Do not use electrical test equipment on the SRS harness unless instructed.” Ignore that and you could deploy an airbag while testing. The manual also includes service bulletins and updates that aftermarket books never see. If you’re doing a cylinder head job, you need the factory warpage limit (0.002 in maximum) and the correct valve seat reconditioning angles (45° seat, 30° top cut, 60° bottom cut). This manual has it all.

Frequently Asked Questions

Does this manual cover the VTEC system on the 1991 NSX?

Yes, the Cylinder Head / Valve Train section includes a dedicated VTEC subsection with oil pressure specs, solenoid testing, and rocker arm inspection. You’ll also find the VTEC engagement RPM and the procedure for checking the spool valve.

Can I use this manual for a 1992 or later NSX?

This manual is specifically for the 1991 model year. Later NSX models had changes to the transmission, suspension, and electrical systems. For a 1992 or newer, you’ll need the corresponding year’s service manual to get accurate torque specs and wiring diagrams.

Is the manual in English and does it use imperial units?

Yes, the manual is written in English and all torque values, clearances, and capacities are given in imperial units (lb-ft, inches, US quarts). Perfect for North American shops and home garages.

If you’re serious about keeping that NSX running like it left the factory, you need the real documentation. Access the Factory Manual now and get the complete 1420-page PDF with every torque spec, wiring diagram, and step-by-step procedure. No more guessing, no more wasted time.

Related Manuals

• Acura Integra Service Manual 1998 – Section: Electrical (Including Srs)
• Acura Vigor Service Manual 1993
• Acura MDX Service Manual 2007

External Resources

• Automotive Industry Overview
• Manual Transmission