Description

Porsche 928 1988 Workshop Manual

If you are working on a 1988 Porsche 928 and you reach for a generic aftermarket PDF instead of the factory book, you are signing up for stripped threads and leaks. I have seen it too many times. The 928 uses a dry-sump oil system, a torque converter lockup that needs specific clearances, and a fuel injection setup that will make you chase ghosts if you trust third-party specs. This Workshop Manual is the same binder the Porsche dealers used. 277 pages, printed in Germany, covering the 1988 model year. There is no guesswork in these pages.

Let me walk you through what is inside and why it matters on the bench.

Repair Groups Organization

The manual is split into repair groups — numbered sections that cover every system. You get Group 10 for Engine, Group 13 for Crankcase, Group 17 for Cylinder Head and Valve Drive, all the way through Group 97 for Wiring. The TOC lists them with page prefixes (like 10-1, 17-1) so you can flip directly to the right section. There is also a general data section at the front with tightening torques. I have used these groups to pull a 928 engine in under four hours because the sequence is laid out step-by-step. It matters. Porsche 928 Workshop Manual – Section: Repair Groups

Torque Converter Removal and Installation

Page 32-101 covers removing and installing the torque converter. The 928 uses a three-speed automatic transmission that is sensitive to converter depth. The manual tells you the exact tool to support the converter, the bolt torque for the drive plate, and the checking procedure for converter end play. If you skip that step, you will blow the front seal on the first test drive. I have seen it happen. Porsche 928 Workshop Manual

Does This Manual Cover the Fuel System and Ignition?

Yes. Repair Group 24 is Fuel Supply, Group 26 is Air Flow Controlled Fuel Injection (the Bosch LH-Jetronic system), and Group 28 is the Ignition System. The manual includes the full diagnostic flow charts, component locations, and pinout data. There is a whole subsection on the digital ignition system used on later 928s. You will find the adjustment specs for idle CO, throttle switch adjustment, and the resistance checks for the hall sender. No reading between the lines — it is all typed out.

7 Major Systems Documented

Engine (groups 10-28) — Transmission (30-39) — Chassis (40-48) — Body (50-74) — Heating/Ventilation (80-87) — Electrics (90-97). Each system has its own repair group index. The transmission section alone covers the torque converter, selector lever cable adjustment, starter locking switch, and full disassembly of the valve body. If you need to rebuild a 928 automatic, you need this book. Porsche 911 Carrera 4 & Carrera 2 1995 Workshop Manual Vol 2 Transmission

OEM vs Aftermarket: Why Factory Print Matters

Aftermarket manuals cut corners. They reprint the TSB figures but leave out the footnotes that say “do not reuse bolts” or “apply Loctite 242 to these threads.” This factory manual has the original warnings and spec tables. The torque values are given in Nm and also in ft-lb. The wiring diagrams are full-color with component numbers that match the car. I have worked with both. Aftermarket costs you time. Factory saves it. And if you are in the middle of a job with a customer waiting, you need the real thing. Automotive Industry Overview

Who Should Use This Manual?

This is for the guy who has a 928 on jack stands and wants to do it right. The hobbyist who knows the difference between a ball joint press and a pickle fork. The professional shop that sees a 928 once a year and needs the exact steps for the rear axle shaft removal. The manual assumes you have basic tools but gives you the specific ones where it matters. You will not find beginner jargon. You will find “remove the driver unit” and “slide the thrust washer onto the input shaft” with torque values at every fastener. Manual Transmission

Will this manual work for a 1987 928?

Yes, the 1988 edition carries forward most procedures from 1987 with updates for the S4 model. The selector lever cable adjustment procedure on page 37-105 is identical.

Does it include wiring diagrams?

Group 97 is dedicated to wiring. It includes circuit diagrams for exterior lights, interior lights, starter, alternator, radio, alarm system, and windshield wipers. The component locations are listed with connector views.

What about torque values for the engine?

The general data section at the front lists tightening torques for cylinder head bolts, main bearing caps, connecting rods, and the oil pump. The values are in Nm and ft-lb. For the 16-valve head, the sequence is given in a multi-step angle-torque procedure.

Is this an original Porsche publication?

It is a scanned factory workshop manual, not a reprint. Every page has the Porsche logo and part number WKD 481 621. The German edition was printed in 1986 for earlier revisions, but this 1988 English version covers the S4.

You can pull a transmission, rebuild the front suspension, or trace an electrical short with this book open on the bench. It is 277 pages of factory-authorized procedure. Stop relying on forum guesses and forum-sourced torque values. Get the book that comes from the people who built the car. Access the Factory Manual and start working with the right specs.