Ignition System - Hitachi Electronic Honda Prelude III

DESCRIPTION

Note. All fuel injected models, as well as some carbureted models use Toyo Denso distributors. See appropriate IGNITION SYSTEM - TOYO DENSO ELECTRONIC article.

Distributors consist of a distributor housing, rotor, and distributor cap. The reluctor, stator, magnets, ignitor and breaker plate assemblies are all located inside the distributor housing.

OPERATION

The reluctor turns with the distributor shaft. As reluctor turns, its external teeth come in line with the stator upright teeth.

As reluctor approaches and passes stator teeth, variations occur in the magnetic field around them. Each time reluctor teeth come in line with and then pass the stator teeth, transistors inside the ignitor are turned off and on.

This results in a magnetic field building and collapsing in the primary circuit of the ignition coil. When this field collapses, a voltage surge occurs in the secondary circuit of the ignition coil. When this occurs, a high voltage spark is fed from the coil, through the distributor rotor and cap to the secondary wiring and spark plugs.

Scheme 1

RELUCTOR-TO-STATOR AIR GAP

Align reluctor teeth with those of stator and check air gap. Rotate reluctor and check air gap at all teeth. (Scheme 2) There should be equal air gap at all teeth. If necessary, loosen screws and reposition stator to provide equal air gaps.

Scheme 2

CENTRIFUGAL ADVANCE

Disconnect and plug vacuum hoses at distributor. Connect timing light and start engine. Increase engine speed. Timing mark "T" should appear to move past pointer toward firewall, indicating an increase in ignition advance. If not, check centrifugal advance mechanism for sticking or binding.

IGNITOR

1. Disconnect wire leads from ignitor. Turn ignition on. Check voltage between Blue wire and ground. Also check voltage between Black/Yellow wire and ground. Battery voltage should be present in both instances.
2. Turn ignition off. Set ohmmeter in x100 range. With ignitor leads still disconnected, check continuity between ignitor terminals. (Scheme 3) There should be no continuity with positive probe on Black/Yellow wire terminal. There should be continuity with positive probe on Blue wire terminal.

Scheme 3

IGNITION COIL

1. Turn ignition off. Disconnect wiring from ignition coil terminals. Connect an ohmmeter across coil terminals. On Accord and Prelude, reading should be 1.06-1.24 ohms. (Scheme 4)
2. On Civic and CRX, reading should be.84-1.02 ohms. Set ohmmeter in x1000 range. Connect ohmmeter leads to ignition coil positive terminal and coil tower terminal.
3. On Accord and Prelude, secondary resistance should be 7400-11,000 ohms. On Civic and CRX, secondary resistance should be 8000-12,000 ohms. If readings are not within specification, replace ignition coil.

Scheme 4

IGNITION WIRES

Carefully remove wires by pulling on rubber boots. DO NOT bend wire or conductor may be broken. Check for corroded terminals, clean if necessary. Connect ohmmeter (on x1000 scale) to each end of ignition wires. Resistance reading should be less than 25,000 ohms. If not, replace wires.

RADIO CONDENSER CAPACITY

Using a condenser tester, check for .38-.56 microfarads.

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

See also:
• IGNITION SYSTEM - TOYO DENSO ELECTRONIC