check engine CHEVROLET CAMARO 1967 1.G Chassis Manual PDF

ENGINE-EIECTRICAI 6Y-3

PERIODIC SERVICING

Since the Battery is a perishable item which requires

periodic servicing, a good maintenance program will

insure the longest possible Battery life.

COMMON CAUSES OF FAILURE

If the Battery tests good but fails to perform satis-

factorily in service for no apparent reason, the following

are some of the more important factors that may point to

the cause of the trouble.

1.
Vehicle accessories inadvertently left on overnight to

cause a discharged condition.

2.
Slow speed driving of short duration, to cause an

3.
undercharged condition.

A vehicle

capacity.
electrical load exceeding the generator

4.
Defect in the charging system such as high resist-

ance, slipping fan belt, faulty generator or voltage

regulator.

5. Battery abuse, including failure to keep the Battery

top clean, cable clamps and posts clean and tight,

and improper addition of water to the cells.

LEVEL INDICATOR

The Battery features an electrolyte level indicator,

which is a specially designed vent plug with a transparent

rod extending through the center (fig. 5b). When the elec-

trolyte is at the proper level, the lower tip of the rod is

immersed, and the exposed top of the rod will appear

very dark; when the level falls below the tip of the rod,

the top will glow. ,

The Indicator reveals at a glance if water is needed,

without the necessity of removing the vent plugs (fig. 6b).

The Level Indicator is used in only one cell (second

cell cap from positive Battery post) because when the

electrolyte level is low in one cell, it is normally low in

all cells. Thus when the Indicator shows water is needed,

check the level in all six cells.

An alternate method of checking the electrolyte level is

to remove the vent plug and visually observe the electro-

lyte level in the vent well. The bottom of the vent well

features a split vent which will cause the surface of the

electrolyte to appear distorted when it makes contact.

The electrolyte level is. correct when the distortion first

appears at the bottom of the split vent (fig. 4b).

ELECTROLYTE LEVEL

The electrolyte level in the Battery should be checked

regularly. In hot weather, particularly during trip driv-

ing, checking should be more frequent because of more

rapid loss of water. If the electrolyte level is found to be

low, then colorless, odorless, drinking water should be

added to each cell until the liquid level rises to the split

vent located in the bottom of the vent well. DO NOT

OVERFILL because this will cause loss of electrolyte

resulting in poor performance, short life, and excessive

corrosion.

CAUTION: During service only water should be

added to the Battery, not electrolyte.

The liquid level in the cells should never be allowed to

drop below the top of the plates, as the portion of the
INDICATOR

ELECTROLYTE LEVEL

CORRECT

Fig.
5b—Cut-Away View Showing Electrolyte at Proper Level

with Indicator Having Dark Appearance

plates exposed to air may be permanently damaged with a

resulting loss in performance.

WATER USAGE

Excessive usage of water indicates the Battery is being

overcharged. The most common causes of overcharge

are high Battery operating temperatures, too high a volt-

age regulator setting, poor regulator ground wire con-

nection. Normal Battery water usage is approximately

one to two ounces per month per battery.

INDICATOR

Fig.
6b—Cut-Away View Showing Electrolyte at Low Level

with Indicator Having Light Appearance

CHASSIS SBtVKZ MANUAL

ENGINE-ELECTRICAL
6Y-4

CLEANING

The external condition of the Battery should be checked

periodically for damage or for the presence of dirt and

corrosion. The top of the Battery should be kept clean.

An accumulation of acid film and dirt may permit current

to flow between the terminals, which will slowly dis-

charge the Battery. For best results when cleaning the

top of Batteries, wash first with a diluted ammonia or a

soda solution to neutralize any acid present; then flush

with clean water. Care must be taken to keep vent plugs

tight, so that the neutralizing solution does not enter the

cells.

CABLES

To insure good electrical contact, the cables should be

clean and tight on the Energizer posts. If the posts or

cable terminals are corroded, the cables should be dis-

connected and the terminals and clamps cleaned sepa-

rately with a soda solution and a wire brush. After

cleaning and installing clamps, apply a thin coating of

petroleum jelly on the cable clamps to retard corrosion.

CARRIER
AND
HOLD-DOWN

The Battery carrier and hold-down should be clean and

free from corrosion before installing the Battery. The

carrier should be in a sound mechanical condition so that

it will support the Battery securely and keep it level.

To prevent the Battery from shaking in its carrier,

the hold-down bolts should be tight (60-80 in. lbs.). How-

ever, the bolts should not be tightened to the point where

the Battery case or cover will be placed under a severe

strain.

BATTERY SAFETY PRECAUTIONS

When Batteries are being charged, an explosive gas

mixture forms in each cell. Part of this gas escapes

through the holes in the vent plugs and may form an

explosive atmosphere around the Battery itself if ventila-

tion is poor. This explosive gas may remain in or around

the Battery for several hours after it has been charged.

Sparks or flames can ignite this gas causing an internal

explosion which may shatter the Battery.

The following precautions should be observed to pre-

vent an explosion:

1.
Do not smoke near Batteries being charged or which

have been very recently charged.

2.
Do not break live circuits at the terminals- of Batr

teries because a spark usually occurs at the point

where a live circuit is broken. Care must always be

taken when connecting or disconnecting booster leads

or cable clamps on fast chargers. Poor connections

are a common cause of electrical arcs which cause

BATTERY CHARGING PROCEDURES

There are three methods of recharging Batteries.

They differ basically in the length of time the Battery is

charged and the rate at which charging current is sup-

plied. One is the Slow Charge method, the second is the

Fast Charge method, and the third is the Emergency

Boost Charge method.

Before recharging a Battery by any method, the elec-

trolyte level must be checked and adjusted if necessary.
SLOW CHARGING

The Slow Charge method supplies the Battery with a

relatively low current flow for a relatively long period of

time. This is the only method that will bring the Battery

to a full state of charge.

The Slow Charge method consists of charging at

approximately a 4 ampere rate for 24 hours or more if

necessary to bring the Battery to full charge. A fully

charged condition is reached when the cells are gassing

freely and three corrected specific gravity readings

taken at hourly intervals show no increase.

FAST CHARGING

The Fast Charge method supplies current to the Bat-

tery at a 40 to 50 ampere rate for a 1 1/2 hour period of

time. If the electrolyte temperature reaches 125°F before

the 1 1/2 hour period is completed, the Battery must be

taken off charge temporarily, or the charging rate

reduced to avoid damage to the Battery.

Although a Battery cannot be brought to a fully charged

condition during Fast Charge, it can be substantially

recharged or "boosted". In order to bring the Battery to

a fully charged condition, the charging cycle must be

finished by the Slow Charge method.

EMERGENCY BOOST CHARGING

In cases where the Battery is not sufficiently charged

to crank the engine, an emergency boost charge may be

applied as a temporary expedient in order to crank the

engine. The Emergency Boost Charge method consists of

charging at a 40 to 50 ampere rate for a period of one-

half hour.

It should be particularly noted that the Emergency

Boost Charge will not necessarily restore the Battery to

a useful state of. charge for continued service. After an

emergency boost charge, failure to charge the Battery

further, either by a long uninterrupted driving period or

by the Fast Charge or Slow Charge method, may result

in failure to crank the engine the next time cranking is

attempted. A Battery should never be condemned on the

basis of failure to crank the engine after an emergency

boost charge. Although an emergency boost charge may

put enough energy into the Battery to crank the engine

once, further charging usually is necessary in order to

create a sufficient reserve to crank a second and third

time.

12
VOLT BATTERY SUGGESTED

CHARGING RATES

(100 Amp/hr or Less Capacity)

TYPE OF

CHARGE

Boost Charge for

Light Load Test

Slow Charge

Fast Charge

Quick Boost .

Dry Charge

Warm-up Boost
LENGTH

OF TIME

20 Minutes

24 Hours

1-1/2 Hours

30 Minutes

10 Minutes
CHARGING

RATE

50 Amps

4 Amps

40-50 Amps

40-50 Amps

15 Amps

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE—ELECTRICAL 6Y-5

BATTERY TESTING PROCEDURES

Testing procedures are used to determine whether the

Battery is (1) good and usable, (2) requires recharging or

(3) should be replaced. Analysis of Battery conditions can

be accomplished, by performing a visual inspection,

Instrument Test, and the full charge hydrometer test.

1.
VISUAL INSPECTION

The first step in testing the Battery should be a visual

inspection, which very often will save time and expense

in determining Battery condition.

• Check the outside of the Battery for a broken or

cracked case or a broken or cracked cover. If any

damage is evident, the Battery should be replaced.

« Note the electrolyte level. Levels that are too low or

too high may cause poor performance, as covered in

the section entitled "Periodic Servicing".

o Check for loose cable connections, and for evidence

of corrosion as covered in section entitled ' 'Periodic

Servicing". Correct as required before proceeding

with tests.

2.
INSTRUMENT TEST

A number of suppliers have approved testing equipment

available. These testers have a programmed test proce-

dure consisting of a series of timed discharge and

charge events, requiring approximately 2 to 3 minutes,

that will determine the condition of the Battery with a

high degree of accuracy. When using these testers, the

procedure recommended by the tester manufacturer

should be followed. Batteries should not be charged prior

to testing as doing so may alter the test results. If a

tester is not available for testing, the "Specific Gravity

Cell Comparison Test" may be used or an alternate

method, but with a sacrifice in testing accuracy.

3. FULL CHARGE HYDROMETER TEST

This test should be used only on Batteries which test

good with testing equipment or "Specific Gravity Cell

Comparison Test" but which subsequently fail in service.

• Remove the Battery from the vehicle, and adjust the

electrolyte level as necessary, by adding colorless,

odorless, drinking water.

• Fully charge the Battery at the Slow Charging rate

as covered in the section entitled "Battery Charg-

ing".

• Measure the specific gravity of the electrolyte in

each cell and interpret as follows:

Hydrometer Reading Less Than
1.230—Full
charge

hydrometer readings less than 1.230 corrected for

temperature indicate the Battery is defective and

should be replaced.

Hydrometer Readings Above
1.310—Full
charge hy-

drometer readings above 1.310 corrected for tem-

perature indicate that the cells have been improperly

filled (activation) or improperly serviced. Poor

service and short Battery life will result.

SPECIFIC GRAVITY READINGS

A hydrometer can be used to measure the specific

gravity of the electrolyte in each cell.

The hydrometer measures the percentage of sulphuric
acid in the battery electrolyte in terms of specific

gravity. As a battery drops from a charged to a dis-

charged condition, the acid leaves the solution and enters

the plates, causing a decrease in specific gravity of

electrolyte. An indication of the concentration of the

electrolyte is obtained with a hydrometer.

When using a hydrometer, observe the following points:

1.
Hydrometer must be clean, inside and out, to insure

an accurate reading.

2.
Hydrometer readings must never be taken immedi-

ately after water has been added. The water must be

thoroughly mixed with the electrolyte by charging for

at least 15 minutes at a rate high enough to cause

vigorous gassing.

3.
If hydrometer has built-in thermometer, draw liquid

into it several times to insure correct temperature

before taking reading.

4.
Hold hydrometer vertically and draw in just enough

liquid from battery cell so that float is free floating.

Hold hydrometer at eye level so that float is vertical

and free of outer tube, then take reading at surface of

liquid. Disregard the curvature where the liquid

rises against float stem due to surface tension.

5.
Avoid dropping battery fluid on car or clothing as it

is extremely corrosive. Any fluid that drops should

be washed off immediately with baking soda solution.

The specific gravity of the electrolyte varies not only

with the percentage of acid in the liquid but also with

temperature. As temperature increases, the electrolyte

expands so that the specific gravity is reduced. As

temperature drops, the electrolyte contracts so that the

specific gravity increases. Unless these variations in

specific gravity are taken into account, the specific

gravity obtained by the hydrometer may not give a true

indication of the concentration of acid in the electrolyte.

A fully charged Battery will have a specific gravity

reading of approximately 1.270 at an electrolyte temper-

ature of 80°F. If the electrolyte temperature is above or

below 80°F, additions or subtractions must be made in

order to obtain a hydrometer reading corrected to the

80°F standard. For every 10° above 80°F, add four

specific gravity points (.004) to the hydrometer reading.

Example: A hydrometer reading of 1.260 at 110°F would

be 1.272 corrected to 80°F, indicating a fully charged

Battery. For every 10° below 80°F, subtract four points

(.004) from the reading. Example: A hydrometer reading

of 1.272 at 0°F would be 1.240 corrected to 80°F, indi-

cating a partially charged Battery.

Specific Gravity Cell Comparison Test—This test may

be used when a instrument tester is not available. To

perform this test measure the specific gravity of each

cell, regardless of state of charge, and interpret the

results as follows:

• If specific gravity readings show a difference be-

tween the highest and lowest cell of .050 (50 points)

or more, the Battery is defective and should be

replaced.

INSTALLING BATTERIES

To install a Battery properly, it is important to ob-

serve the following precautions:

• Connect grounded terminal of Battery last to avoid

short circuits which may damage the electrical

system.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-6

DO NOT SUCK

IN TOO MUCH

ELECTROLYTE

FLOAT MUST

BE FREE

TAKE READING

AT EYE LEVEL
• Be sure there are not foreign objects in the carrier,

so that the new Battery will rest properly in the

bottom of the carrier.

• Tighten the hold-down evenly until snug (60-80 in.

lbs.).
Do not draw down tight enough to distort or

crack the case or cover.

• Be sure the cables are in good condition and the

terminal clamps are clean and tight. Make sure the

ground cable is clean and tight at engine block or

frame.

• Check polarity to be sure the Battery is not reversed

with respect to the generating system.

Fig.
7b—Testing Specific Gravity

Fig.
8b--Battery Installation (Corvette Shown)

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-7

CHARGING SYSTEM

INDEX

Page

General Description . 6Y-7

Maintenance and Adjustments 6Y-9

Static Checks . 6Y-10

System Condition Check and Voltage

•Regular Adjustment. 6Y-10

General Output 6Y-11

Generator Diode and Field Test 6Y-12

Indicator Lamp-Initial Field Excitation

Circuit Tests . 6Y-12
Page

Field Circuit Resistance Wire Tests 6Y-13

Field Relay Test and Adjustment 6Y-14

Other Harness Checks 6Y-14

Service Operations 6Y-14

Generator 6Y-14

Removal and Installation 6Y-14

Pulley Replacement. 6Y-14

Brush Replacement (6" Delcotron). 6Y-15

Double Contact Regulator . . . . . . 6Y-16

GENERAL DESCRIPTION

The charging system includes the battery, generator,

regulator, telltale light, and necessary wiring to connect

these components. The Delcotron is offered as standard

equipment, although there are various capacities avail-

able on all models.

The Delcotron continuous output A.C. generator (fig.

lc) consists of two major parts, a stator and a rotor. The

stator is composed of a large number of windings as-

sembled on the inside of a laminated core that is attached

to the generator frame. The rotor revolves within the

stator on bearings located in each end frame. Two

brushes are required to carry current through the two

slip rings to the field coils wound concentric with the

shaft of the rotor. Six rectifier diodes are mounted in the

slip ring end frame and are joined to the stator windings

at three internally located terminals.

Diodes are mounted in heat sinks to provide adequate

heat dissipation. The six diodes replace the separately
mounted rectifier as used in other types of application.

The diodes change the Delcotron A.C. current to D.C.

current.

Two regulators (fig. 2c) are available on the 1967 vehi-

cles,
a double contact two unit type and a transistor

regulator. The function of these regulators in the charg-

ing system is to limit the generator voltage to a pre-set

value by controlling the generator field current. Both

regulators have an internal field relay unit. The relay

unit allows the telltale lamp to light (as a bulb check)

with the ignition key on and engine not running. When the

engine is started and the generator begins to charge, the

indicator light goes out indicating that the system is op-

erating normally.

The double contact regulator, when used with the

special 63 amp air conditioning model generator (4 ohm

field coil) uses a field discharge diode internally in the

field circuit (figs. 3c and 4c). The added diode adapts the

BRUSH AND

TERMINAL

ASSEMBLY

SLIP RINGS
SLIP RING

END FRAME

_\

THRU

BOLT
DRIVE END

FRAME

BEARING

BEARING

DIODES

ROTOR

5.5" SERIES ID DELCOTRON
STATOR

ASSEMBLY
GREASE

RESERVOIR

BRUSH

FAN ASSEMBLY

6.2" SERIES 2D TYPE 150 DELCOTRON

Fig.
lc—Delcotron Cross-section View

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-9

63 AMP 1

MODELS ONLY'
BATTERY FUSIBLE

LINK
HORN

FUSIBLE LINK'
TRANSISTOR
FUSIBLE LINK'

Fig.
4c— Circuitry - Voltage Regulator Assemblies (Corvette)

Engine compartment wiring harness incorporates sev-

eral fusible links. Each link is identified with its gage

size. A fusible link is a length of special wire (normally

four wire gages smaller than the circuit it is protecting)

used in wiring circuits that are not normally fused, such

as the ignition circuit. The same size wire with a hypalon

insulation must be used when replacing a fusible link.

The links are:

1.
The pigtail lead at the battery positive cable (except

Corvette) is a 14 gage, brown fusible link protecting

the 10 gage battery charging circuit. This wire is an

integral part of the battery cable assembly and serv-

icing requires replacing the complete battery cable

assembly. On Corvette models this link is installed

as a molded splice at the solenoid "Bat" terminal

and servicing requires splicing in a new link.

2.
A 16 gage black fusible link is located at the horn
4.
relay to protect all unfused wiring of 12 gage or

larger. It is installed as a molded splice and serv-

icing requires splicing in a new link.

The generator warning light and field circuitry (16

gage wire) is protected by a fusible link (20 gage

orange wire) used in the "battery feed to voltage

regulator #3 terminal" wire. The link is installed as

a molded splice in the generator and forward lamp

harness and is serviced by splicing in a new 20 gage

wire as required.

The ammeter circuit on all models is protected by

two orange, 20 gage wire fusible links installed as

molded splices in the circuit at the junction block or

the solenoid "Bat" terminal (Corvette only) and at

the horn relay. Each link is serviced by splicing in a

new 20 gage wire as required.

MAINTENANCE AND ADJUSTMENTS

At regular intervals, inspect the terminals for cor-

rosion an4 loose connections, and the wiring for frayed

insulation. Check mounting bolts for tightness. Check the

drive belt for alignment, proper tension and wear. Be-

cause of the higher inertia and load capacity of the rotor

used in A.C. generators, PROPER BELT TENSION is

more critical than on D.C. generators.

Since the Delcotron and its companion regulator are

designed for use on negative polarity systems only, the

following precautions must be observed. Failure to ob-

serve these precautions may result in serious damage to

the charging system.

1.
When installing a battery, always make absolutely

sure the ground polarity of the battery, generator and

regulator is the same.

2.
When connecting a booster battery, make certain to

connect the correct battery terminals together.

3.
When connecting a charger to the battery, connect the

correct charger leads to the battery
%
terminals.

4.
Never operate the generator on an uncontrolled open
TO SOLENOID

BAT ACC RES. WIRE

Fig.
5c—Typical Wiring Diagram Showing Lead Connections

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-10

circuit. Make absolutely certain all connections in

the circuit are secure.

5.
Do not short across or ground any of the terminals

on the generator or regulator.

6. Do not attempt to polarize the generator.

7.
Do not disconnect lead at generator without first dis-

connecting battery ground cable.

Trouble in the A.C. charging system will usually be

indicated by one or more of the following conditions:

1.
Faulty indicator lamp or ammeter operation.

2.
An undercharged battery (usually evidenced by slow

cranking speeds).

3.
An overcharged battery (usually evidenced by exces-

sive battery water usage).

4.
Excessive generator noise or vibration.

Described below are a series of on-the-vehicle quick

checks which are designed to assist the service tech-

nician in locating troubles within the various components

of the engine electrical system. Additional checks, ad-

justments and overhaul procedures of these components

are also described in the "Charging Systems—Service

Operations Section" and should be referred to as

necessary.

STATIC CHECKS

Before making any electrical checks, perform the fol-

lowing static checks:

1.
Check for loose fan belt.

2.
Check for defective battery. (Refer to Battery).

3.
Inspect all connections, including the slip-on con-

nectors at the regulator and Delcotron.

NOTE: Do not short field to ground to check if

generator is charging since this will seriously

damage the charging system.

SYSTEM CONDITION TEST

This test is used .to indicate the overall condition of the

charging system (both good and defective) and to isolate

the malfunctioning unit if the system is defective.

NOTE: On Corvette models difficulty may be

encountered -when attempting to make the re-
quired test connections at the voltage regulator.

It is advisable to remove the regulator from its

mounting location to perform the necessary con-

nections at the regulator for the following tests

but make sure unit is grounded.

1.
With ignition off, perform the prescribed Static

Checks outlined in this section. Then set hand brake

and shift transmission
into
neutral.

2.
Connect a voltmeter from junction block relay to

ground at regulator base.

CAUTION: Be sure meter clip does not touch a

resistor or terminal extension under regulator,

3.
Connect a tachometer on engine.

4.
Models equipped with Indicator Lamp: Turn ignition

switch on "ON" position and check indicator lamp.

If lamp fails to glow, perform appropriate tests and

corrections (Indicator Lamp Circuit Tests) before

continuing.

Models equipped with Ammeter: Turn ignition

switch to "ACC" with an accessory on and check

ammeter. If ammeter fails to read discharge, check

ammeter circuit before continuing.

5.
Models equipped with Indicator Lamp: If lamp glows,

start the engine and run' it at 1500 rpm or above.

Check indicator lamp. If lamp fails to go out, per-

form appropriate test and corrections (Indicator

Lamp Circuit Test) before continuing.

Models equipped with Ammeter: If ammeter reads

discharge, start the engine and observe ammeter. If

meter fails to move toward charge (from original

position), perform appropriate test and corrections

(Field Circuit Tests) before continuing.

NOTE: At this point a field circuit has been

established and any other problem will lie in

generator or regulator.

6. Turn on high-beam headlights and heater blower

motor to high speed, run engine at or above 1500

rpm (for a few minutes, if necessary) and read the

voltage on meter.

AIR GAP

ADJUSTING NUT

ONLY

ADJUSTING SCREW

(Turn To Adjust

Voltage Setting)

Fig.
6c—Adjusting Voltage Setting

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-J2

Fig.
8c—Ammeter Method Test Connections

10.
Turn off ignition, disconnect battery ground cable,

and remove all test equipment.

11.
li the Delcotron meets the test specifications, the

problem is not in the generator.

12.
Ti the Delcotron fails to meet the test specifications,

remove it and perform bench tests and make repair

needed.

DELCOTRON DIODE AND FIELD TEST (Fig. 9c)

NOTE:
These tests will indicate good,, shorted

or open field or shorted diode but will not indi-

cate a failed open diode. If output was low and

following tests show good, refer to service op-

erations to determine cause and repair.

1.
Disconnect battery ground cable at battery.

2.
Positive diodes (Test A) connect an ohmmeter be-

tween "R" terminal and "BAT" terminal and note

Fig.
9c-Deicotron Diode and Field Test
reading, then reverse the leads at same terminals

and note this reading. Meter should read high re-

sistance in one direction and low in the other.

3.
Negative diodes (Test B) connect ohmmeter between

"R" terminal and "GRD" and note reading, then

reverse the leads and note this reading. Meter

should read high in one direction and low in the

other.

NOTE:
A high or low reading in both directions

indicates a defective diode.

4.
Open Field Check:

a. Connect an ohmmeter from "F" terminal to

"GRD"
terminal stud and note reading on the

lowest range scale. Meter should read 7 to

20 ohms.

b.
If meter reads zero or excessively high resist-

ance, the Delcotron is faulty.

5. If above tests indicate a defective Delcotron, remove

and completely check Delcotron as outlined under

''Service Operations".

INDICATOR LAMP/INITIAL FIELD

EXCITATION CIRCUIT TESTS (Fig. 10c)

On standard models the indicator lamp circuit provides

initial field excitation (causing lamp to glow). The light

is cancelled by closing the field relay which applies bat-

tery voltage to both sides of bulb (bulb goes out).

The indicator light should glow when ignition switch is

"ON"
and go out almost immediately when engine starts.

Ammeter equipped vehicles use the same initial field

excitation and control circuits as the indicator lamp ex-

cept the lamp is omitted. The continuity tests on both

type vehicles can be made as follows:

If Lamp Fails to Glow or Ammeter Fails to

Function the Possible Causes are:

1.
Faulty bulb or bulb socket.

2.
Faulty ammeter.

3.
An open circuit in wiring, regulator, or field.

4.
A shorted positive diode—(may also cause glow with

ignition switch "OFF").

TEST AS FOLLOWS:

1.
Disconnect connector from regulator and turn

ignition switch to "ON". Connect a test lamp from

connector terminal "4" to ground (fig. 10c, Step 1)

and note test lamp.

a. Lamp fails to glow—check for faulty bulb, socket

or open circuit between switch and regulator con-

nector. Repair as needed.

b.
Light goes on—failure is in regulator, Delcotron,

or wire between "F" terminals on regulator and

Delcotron. Go to Step 2.

2.
Disconnect lamp lead at ground end and connect be-

tween connector "F" and "4" terminals (fig. 10c,

Step 2), and note lamp:

a. Test Lamp glows—problem is in regulator. An

open circuit in regulator or relay is stuck dosed.

See "Service Operations" for repair.

b.
Fails to glow—problem is in wire between "F"

terminals on generator and regulator or infield

windings. Go to Step 3.

3.
Disconnect test lamp at connector "F" terminal and

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-13

F 2 3 4

f 2 3 4

F 2 3 4

Fig.
10c—Initial Field Excitation Circuit Tests

connect to "F" terminal on Delcotron (fig. 10c,

Step 3), and note lamp:

a. Lamp glows-an open circuit in wire between "F"

terminals—correct as needed.

b.
Fails to glow—Delcotron field has open circuit,

see "Service Operations" to repair %

If Lamp Fails to Go Out, or if Ammeter Shows

Discharge the Possible Causes are:

1.
Loose drive belt—adjust as necessary.

2.
Faulty field relay—(see relay test and adjustment).

3.
Defective Delcotron—(see Delcotron output test).

4.
At normal idle—parallel resistance wire open (see

Resistance test). On ammeter models the initial

field excitation wire to "ACC" terminal is open.

5. Switch off—positive diode shorted (see Diode test).

FIELD CIRCUIT RESISTANCE

WIRE CHECKS

The resistance wire is an integral part of the ignition

harness. However, the resistance wire is not solderable;

it must be spliced with a crimp-type connector. It is

rated at 10 ohms, 6.25 watts minimum.

The check for an open resistor or field excitation wire

(connected to the ignition switch "ACC" terminal) is as

follows:

1.
Connect a test lamp from the wiring harness con-

nector terminal "4" to ground as shown in Figure

10c (Step 1).

2.
Turn the ignition switch to the "ON" position and

note test bulb.

a. Test lamp glows—resistance is O.K.

b.
Test lamp does not glow—the resistor is open

circuited—note also that dash lamp does not glow

during this test because series resistance of the

2 bulbs causes amperage to be too low.
VOLTMETER

3 4

WIRING*
HARNESS

CONNECTOR

Fig.
11c—Testing Field Relay

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE-ELECTRICAL 6Y-14

VOLTMETER

WIRING HARNESS

CONNECTOR

Fig.
12c—Field Relay Closing Voltage Test

FIELD RELAY CHECKS AND ADJUSTMENT

To check for a faulty relay proceed as follows:

1.
Connect a voltmeter into the system at the regulator

No.
2 terminal to ground (fig. lie).

2.
Operate the engine at fast idle (1500 to 2000 rpm) and

observe voltmeter reading.

3.
If voltmeter shows zero voltage at regulator, check

circuit between No. 2 terminal on regulator to "R"

terminal on Delcotron.

4.
If voltage at regulator exceeds closing voltage
Fig.
13c—Adjusting Field Relay Closing Voltage

specification and light remains on, regulator field

relay is faulty (Refer to specifications). Check and

adjust regulator as follows:

CLOSING VOLTAGE ADJUSTMENT

•1.
Make connections as shown in Figure 12c using a 50

ohm variable resistor.

NOTE: This gives us a variable resistance in

series from a hot lead to the relay coil.

2.
Turn resistor to "open" position.

3.
Turn ignition switch off.

4.
Slowly decrease resistance and note closing voltage

of the relay. Adjust by bending heel iron in the man-

ner illustrated in Figure 13c.

OTHER HARNESS CHECKS

Other wires in the charging system harness need be

checked for continuity by use of an ohmmeter or a test

ligjit (12 Volt). Connect the test so the wire in question is

in series in the test circuit.

SERVICE OPERATIONS

Service Procedures described in this section are for

the 5.5" aluminum and 6.2" perforated stator Delcotrons

(fig. 14c). Where important differences are encountered

separate mention will be made of the two generators.

GENERATOR

REMOVAL AND INSTALLATION

1.
Disconnect the battery ground strap at battery to

prevent damaging diodes.

2.
Disconnect wiring leads at Delcotron.

3.
Remove generator brace bolt, (if power steering

equipped, loosen pump brace and mount nuts) then

detach drive belt (belts).

4.
Support the generator and remove generator mount

bolt (6.2" Delcotron uses 2 mount bolts) and remove

from vehicle.
5.
Reverse the removal procedure to install then adjust

drive belt.

PULLEY REPLACEMENT

5.5" Delcotron

Single Groove Pulley

1.
Place 15/16" box wrench on retaining nut and insert

a 5/16" alien wrench into shaft to hold shaft while

removing nut (fig. 15c).

2.
Remove washer and slide pulley from shaft.

3.
Reverse Steps 1 and
2
to install, use a torque wrench

with a crow-foot adapter (instead of box wrench) and

torque the nut to 50 ft. lbs. (fig. 16c).

Double Groove Pulley

1.
Place a 15/16" socket (with wrench flats on the drive

CHEVROLET CHASSIS SERVICE MANUAL