1973 OPEL GT-R ECU

CC-10 1973 OPEL SERVICE MANUAL
wiper blades. Check amount and direction of fluid
sprayed by washers during use.,
E. Defrosters - Check performance by moving con-
trols to “DEF” and noting
am$nmt of air directed
against the windshield.
I
F. Wheel Alignment and
Balabce - In addition to
abnormal tire wear, the need fbr wheel alignment
service may be indicated by a pull to the right or
!eftwhen driving on a straight and level road. The need
for wheel balancing is usually
iddicated by a vibra-
tion of the steering wheel or
se;+ tihile driving at
normal highway speeds.I
IG. Brakes
- Be alert to illumiriation of the brake
warning light or changes in braking action,
SUCK as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Any of thesecould indicate the need for
brakk system inspection
and/or service.
H. Parking Brake and Transmission “PARK”
Mechanism
- Check parking brake holding ability by
parking on a fairly steep hill and restraining the vehi-
cle with the parking brake only.
eon cars with auto-
matic transmissions, check the holding ability of the
“PARK” mechanism by releasing all brakes after
the transmission selector lever hak been placed in the“P” position.
I. Glass
- Check for broken, scrritched, dirty or da-
maged glass on vehicle that
coulld obscure vision’or
become an injury hazard.
J. Lights and Buzzers
- Check all instrument panel
illuminating and warning lights,’ seat belt reminder
light and buzzer, ignition key
b&er, interior lights,
license plate lights, side marker! lights, headlamps,
parking lamps, tail lamps, brake lights, turn signals,
backup lamps, and hazard warding flashers. Have
someone observe operation of
&ach exterior light
while you activate the controls: The operation of
instrument panel warning lights is covered in the
“Starting and Operating“ section of your
Own&%
Manual.K. Transmission Shift Indicator
‘- Check to be sure
automatic transmission shift
indiCator accurately i”-
dicates the shift position selected.
I
CAUTION: Before making thk check below,I
be sure to have a clear dist&e ahead and:
behind the car, set the parking brake and
firmly apply the foot brake.
Do not depress
accelerator pedal. Be prepared to
turn off ’
ignition switch
immediat+y if engine
should start.L. Starter Safety Switch (Automatic Transmissibn
Cars)
- Check starter safety switch by placing the
transmission in each of the driving gears while
at-tempting to start the engine. The starter should oper-ate only in the Park (“P”) or Neutral (“N”)
positions.
M. Horn
- Blow the horn occasionally to be sure thatit works. (Ignition switch must be in the “ON” posi-
tion.)
N. Seat Back Latches
- Check to see that seat back
latches are holding by pulling forward on the top of
each folding seat back.
0. Rearview Mirrors and Sun Visors
- Check that
friction joints are properly adjusted so mirrors and
sun visors stay in the selected position.
P. Door Latches
- Check for positive closing, latch-
ing and locking.
Q. Hood Latches - Check to make sure hood closesfirmly by pressing on the hood at the latching point
after each closing. Check also for broken, damaged
or missing parts which might prevent secure latch-
ing.R. Fluid Leaks
- Check for fuel, water, oil or other
fluid leaks by observing the ground beneath the vehi-cle after it has been parked for a while. If gasoline
fumes or fluid are noticed at any time, the cause
should be determined and corrected without delay
because of the possibility of fire.
S. Exhaust System
- Be alert to any change in the
sound of the exhaust system or a smell of fumes
which may indicate a leak.
Head Restraints
- Check that no head restraint
components are missing, damaged or loose. (Does
not apply to GT Models).
Disc BrakesCheck brake pads and condition of rotors while
wheels are removed during tire rotation. (Note belowregarding more frequent checks also applies to disc
brakes.)
Parking and Drum BrakesCheck drum
brake linings and other internal brake
components at each wheel (drums, wheel cylinders,
etc.). Parking brake adjustment also should be
checked whenever drum brake linings are checked.
NOTE: More frequent checks should be
made if driving conditions a.nd habits result
in frequent brake application. When brakes
require relining, it is recommended thatyou use those genuine General Motors
parts specified for your car,and Delco fluid
as required.

1A. 4 1973 OPEL SERVICE MANUAL
gravity corrected to 80 degrees F.’ shows more than
a thirty point
(.030) drop from the initial tilling with
electrolyte, or if one or more cells’gas violently after
addition of electrolyte, the batteiy should be fulty
charged before use.
3. For best performance in cold weather (32 degrees
F. or less), or if the battery and the electrolyte are not
at 60 degrees F., or above at time of activation, warm
the battery by boost charging.
TROUBLE DIAGNOSIS
BATTERY AND CABLES. TRDUBLE DIAGNOSIS
Quick Check of Battery and Cables
Whenever electrical trouble developes, it is desirable
to make a quick check of the battery and cables to
make certain that this source of current is in good
condition, securely connected, and is functioning
properly. This check will also give a good check on
the cranking system.
1. Turn on the lights. They should’burn steadily and
with normal brilliance.
2. With lights burnings, operate the cranking motor.
Either have the headlights shining on a wall so their
brilliance can be noted, or have someone watching
the headlights.
3. When cranking motor solenoid switch is
closeh,one of the following conditions will occur; (1) Lights
will stay bright or will dim slightly if temperature is
cold, and engine will be cranked at normal speed; (P
Lights will
gb out; (3) Lights will dim considerably;
(4) Lights will stay bright but no cranking action will
take place. The first named condition indicates that
nothing is wrong with the battery, cables, and crank-
ing system. The other conditions indicate trouble
aSfollows:
4. If fightsgo
out as cranking motor solenoid switch
is closed, it indicates a poor connection in the circuit
between battery and cranking motor. Check battery
cables and clean and tighten loose or corroded termi-
nals.
5. If
lights dim considerably as cranking motor
solenoid switch is closed, it indicates that the battery
is run down, or there is a condition in cranking
mb-tor or engine which causes an excessive current drain
on the battery. A low battery will be indicated by ,a
clattering noise in cranking motor solenoid because
the battery cannot sustain the voltage required to
hold solenoid plunger “in” after switch contacts
close and the “pull in” winding is shorted out.
Test battery with a 421 Battery Test. If battery is
found to be in good condition check cranking motor.
6.Iflights stay bright but no cranking action occurswhen cranking motor solenoid switch is closed, it
indicates an open circuit in cranking motor, switch,
or control circuit.
Testing Resistance of Cables and Terminal
Connections
Battery cables and terminal connections may be
tested with equipment comprising of a voltmeter (5
volts maximum), ammeter of 300 or more amperes
capacity, and carbonpile rheostat having a minimum
capacity of 300 amperes connected in series with the
ammeter.
I. Adjust rheostat to provide maximum resistance
(“OFF” position).
2. Connect ammeter positive lead to post on starting
motor. Connect ammeter negative lead to one side of
rheostat and connect other side of rheostat to ground
on engine, preferably at point where battery ground
strap is attached. In the instrument shown in FigurelA-1, the ammeter and rheostat are connected in
series inside the case.
3. Connect voltmeter negative lead to post on start-
ing motor. Use prod with voltmeter lead, if neces-
sary, to insure direct contact with the terminal stud.
Do not connect to the ammeter lead clip.Attach a
prod to voltmeter position lead and apply the prod
to center of battery positive post (Figure lA-1.)
Make sure that clips of voltmeter leads have clean
metal contact with prods.
Figure l A-l Battery Cable Test Connections
4. Adjust rheostat until ammeter reads 200 amperes,
immediately read voltmeter, then turn rheostat to
starting (“OFF”) position to avoid excessive drain on
battery. Voltage drop across battery positive cable

BATTERY AND CABLES - ALL MODELSlA- 5
and terminal connections should not exceed 2/10
volt.
5. Connedt voltmeter positive lead to ground on en-
gine.
At&h prod to voltmeter negative lead and
apply prod to center of battery negative post. Volt-
age drop across the battery ground cable and termi-
nal conne$tions should not exceed 2/10 volt at
200amps.
6. A reading in excess of 2/10 volt when testing
either battery cable indicates excessive resistance in
cable or cpnnections. Clean and tighten cable or con-
nections. Clean and tighten cable terminals
(sub-para. c, below) and recheck for voltage drop. If volt-
age drop Still exceeds 2/10 volt, replace cable with a
genuine Buick-Opel cable to insure ample capacity.
Undercharge Failure of BatteryThe most frequent trouble experienced with storage
batteries is failure to maintain a state of charge suffi-
cient to crank the engine and also furnish current to
the ignitibn system, lights and accessories. Failure to
maintain a proper state of charge may be due to one
or more of the following conditions:
1.
Opertiting Conditions. When determining cause
of premature failure of a battery, consideration must
be given /to the conditions under which the car is
operated.,
In very low temperatures the capacity of a storage
battery
ii considerably reduced and the energy re-
quired f& cranking the. engine is considerably in-
creased. :
Frequent starting, particularly in cold weather,
ac-compani the batteqy for cranking than the generator can re-
place in the limited running time. This condition is
aggravated by night driving when lights are turned
on, or by operation of an air conditioner in heavy
traffic.
When thk car is operated under these conditions,adjusting,the voltage regulator to the high limit may
allow enough increase to keep the battery at a safe
state of charge. If the high limit setting does not
maintain a safe state of charge, an occasional booster
charge should be given to the battery.
2. Low charging Rate. In case of premature battery
failure, tbe charging rate of alternator should always
be checked and adjusted if below specifications.
3.
Zntemd Condition The internal condition of the
battery niay be such that it cannot hold a chargesatisfactoiily. Check electrolyte level and test the
battery using the 421 Battery Test.
Overcharge Failure of BatteryA common cause of battery failure is overcharging,
that is, continued input of excessive charging current
after the battery has reached a fully charged condi-
tion.
One evidence that battery is being overcharged is the
need for frequent addition of water to the battery in
order to maintain the electrolyte level above the tops
of the battery separators, since overcharging causes
rapid water loss. When this becomes evident, the
charging rate of alternator should be immediately
checked, as well as the voltage regulator, and ad-
justed to avoid internal damage to battery.
ADJUSTMENTS AND MINOR SERVICEPERIODIC BATTERY INSPECTION AND SERVICE
The battery requires very little attention, but peri-
odic inspection is essential to secure the maximum
efficiency and life. The following services are essen-
tial to maintain the battery at maximum efficiency.
WARNING: Never expose battery to open flame or
electric spark
- battery action generates hydrogen gas
which is flammable and explosive. Do not allow bat-
tery fluid to contact skin, eyes, fabrics or painted
surfaces
- fluidis a sulfuric acid solution which could
cause serious personal injury or property damage.
Wear eye protection when working with battery.
Maintain Electrolyte LevelAdd distilled water as required to maintain the elec-
trolyte level at the split ring at bottom of tiller well.
See Figure IA-2.
Figure lA-2
Battery Filler Well

j
/lA- 61973 OPEL SERVICE MANUAL
Do not overfill, as electrolyte may
be sprayed out by
gassing or may overtlow due to heat expansion dur:
ing charging.
If distilled water is not available, it is better to add
clean, mineral-free tap water than to allow the
elec2trolyte level to remain below the top of the plates:
In freezing weather the water should be added just
before using the car or otherwise charging the bat-
tery so that the water will be mixed with the acid
before it is allowed to stand in freezing temperatures.
If it is found necessary to add water to the
batterimore frequently than about every
1,ooO miles and the
quantity of water added per cell is’ excessive, check
setting of voltage regulator and adjust, if necessary:
Abnormal water loss is an indication that the battery
is being overcharged.
Inspect Battery, Mounting and Cables
Check outside of battery for damage or signs of se&ous abuse such as broken case or broken covers:
Check inside of battery by removing the vent caps
and inspecting for signs of abuse
stich as electrolyte
level too low to see, or bad or unusual odors. If
battery shows signs of serious damage or abuse, it
should be replaced.
Check the battery hold down bolts to make certain
that battery is securely held in place. The nut should
be drawn up to 20 lbs. in.;excessjve tightening may
distort or crack the battery case.If the top of battery is dirty or the hold down str?e
is corroded, clean thoroughly with a brush dipped
IFammonia or soda solution. Care must be used td
prevent any solution from getting into battery
cellslAfter the foaming of solution stops, flush off witli
clean water and dry thoroughly. If hold down strap
is corroded it should be painted with acid-resisting
paint after cleaning.
Check battery cables to make certain they are tight
at bracket and junction block. If a connection is
found loose it should be cleaned before being tight;ened as arcing and corrosion may have taken place
in the loose connection. Check condition of cables
and replace if badly corroded or frayed.
Special attention must be given to,the battery posi-
tive cable position to eliminate the possibility of con-
tact with the exhaust manifold on the 1.1 liter engine.
The cable clamp must be rotated clockwise as neces-
sary for the cable to run at a 45 degree angle toward
the right wheelhouse panel.
Cleaning Cable Terminals
If loose connections are found by inspection, or highresistance is found by voltage test, disconnect the
cable for thorough cleaning of terminals. When
removing a corroded cable terminal from battery
post, do not pry against battery case or hammer on
terminal to break it loose, since either practice will
result in broken cell covers. Use a screw-type termi-
nal puller if terminal cannot be loosened by hand.
Thoroughly clean all corrosion from disconnected
battery cable terminals and terminal posts, using
suitable wire brushes. If wire brushes are not availa-
ble, corroded terminals may be cleaned by brushing
with a strong soda solution, using care not to get
solution into battery cells.
If
cabbz strands are broken, corroded, or loose in
terminals, the cable should be replaced with the cor-
rect cable to insure ample capacity.
To prevent corrosion of battery terminals and con-
nections, apply a coating of petroleum jelly over the
battery post and cable terminals after cables have
been installed on terminals.
421 BATTERY TEST421 Battery Testers, manufactured and sold by a
number of companies, are the only battery testers
approved by Delco-Remy Division for testing one-
piece cover batteries. They are also used by United
Motors Service to determine whether or not a battery
is defective.
Figure lA-3 421 Battery Tester-Charger
The
42,l Battery Tester shows, in a few minutes, the
state-of-charge of the battery and whether it is good
or bad. The tester can be used with any 12 volt
battery, in or out of the car. The test can be made
regardless of the state of charge of the battery; it can
also be made when the electrolyte level is low
- even
below the top of the plates.

19- 12 1973 OPEL SERVICE MANUAL :ConditionPosiible CauseCorrection4. Voltage drop.1. Check wiring and wiring
connections.
5. Overrun&g clutch slips.1. Replace overrunning clutch.
The cranking motor keeps
on rotating after ignition
switch is off.1. Ignition
{witch does not
cut off or solenoid switch
sticks.
1, Immediately disconnect cranking
motor cable from battery. Inspect
and/or replace or repair ignition and
solenoid switches as required.
The drive pinion does notdemesh after engine has
been cranked.1. Drive pinion or ring gear
1. Clean components as specified.
teeth clogged or flattened.Replace as required.
Return spring slack or broken.MAlNTEilANCE AND ADJUSTMENT
/
STARTING SYSTEM CHECKS
Voltage Loss ChecksWhen the starter cranks too slowly, check the bat-
tery state of charge and all electrical connections
between the battery and starter.
1. Turn on headlights and
opera’te starter. If head-
lights dim considerably when starter is engaged, the
battery may be discharged or be defective. Check the
battery.
2. If the headlights stay bright but the starter d&s
not turn over, the starter cables may be faulty or the
starter defective.
(a) Test battery voltage while cranking engine
1(9volts minimum).
(b) Check voltage from starter tkrminal of solenoid
to starter frame while cranking engine.
3. The difference in readings taken in Operations 2a
and 2b above represents the
volt& drop through the
cables and solenoid switch. Voltdge drop should
Gotexceed
.5 volt.
4. Locate excessive resistance as follows:
(a) Turn voltmeter to scale above 12 volts and con-
nect voltmeter leads
across connection or switch: to
be checked.
(b) With starter switch closed, turn voltmeter switch
to lowest scale and take reading as quickly as possi-
ble, then turn switch back to higher scale and stop
cranking engine.(c) Voltmeter must not read more than
.2 volt across
any
c:onnection. If voltmeter reads more than .2 volt,
the
d~efect must be corrected.
Starter Current Draw - Lock Test1. Make sure battery is fully charged and in good
condition.
2. Connect a volt ampere starter tester according to
manufacturer’s instructions.
3. Pull parking brake on securely, shift transmission
into 4th (direct) gear and actuate starter. (Starter will
not
t,urn engine because engine is locked through
transmission.)
4. While starter is actuated, read voltage and current.
Refer to Specification Chart.
(a) Voltage low
_ poor battery or a voltage loss in the
starter circuit.
(b) Current high
- short circuit in starter. Overhaul
starter.
(c) Current low
- commutator dirty, brushes worn,
solenoid switch contacts defective or open circuit in
starter. Overhaul starter.
Starter Current Draw. On Car1. Bring engine to normal operating temperature.
2. Stop engine and disconnect coil wire from dis-
tributor.
3. Ground coil wire to prevent excessive coil voltage
build up.

STARTING SYSTEMlB- 17
7. Seal area between solenoid and frame. See FigurelB-17.
8. With brushes and spring in housings held in place
with a 29 @llimeter socket, slide frame assembly in
position.
9. Install i+ulating sleeves in field frame.
10. Install knd frame and replace through bolts and
tighten bolts.
11. Install bolt holding field frame to solenoid.
SPEClFltjATlONS
Starter SpecificationsStarterNumber. . . .
.._.._..._...........................RatedVoltage
. . . . . . . . . . . . . . . . . . . . . . . . .No voad Test:
...............................................EF 12V0 .8 PS
.....................................................................12Volts
................................................................................................................................10.6Amperes
........................................................................................................................30-50RPM
......................................................................................................................7300-8500Cranking Amperes Test (InCar-Engine atOperating Temp.)
..................................175-205
Lock Test:
Volts
............................................................................................................................6 Min.
Amperes
....................................................................................................................280-320Volt$geRequiredtoCloseSolenoidContacts
....................................................................7.5MinimumDiameterof Commutatorin
Inches................................................................1.46Brush Spring Pressure in Ounces
....................................................................................40-46Minimum Length of Brushes in Inches...............................................................................2812. Check starter on bench before installing.
Starter Installation
1. Hold starter in position.
2. Install two bolts, one nut and lockwashers.
Tighten securely.
3. Install support bracket. To ensure a stress-freeintitallation, install bolt and two nuts only finger
tight. First tighten the bolt at the engine, then tighten
the two nuts at the starter end frame.

IGNITION SYSTEMlC-214. Rota&distributor counterclockwise slightly until
contact pbints just start to open. This must be done
very carefully or engine will not start.
5. Install distributor cap. Make sure spark plug wires
are correctly installed in distributor cap, through clip
and on spark plugs.
Finish TimingIContact boint gap
(.016” at widest gap) or dwell 50
degrees plus or minus 3 degrees should always be
checked before adjusting ignition timing.
1. Connekt timing light to No. 1 spark plug.
2. Disconnect and plug vacuum advance unit and
retard u$it hoses.
3. Connect a tachometer from distributor side of coil
to
groun$l.4. Start dngine. Set idle speed to 900 RPM.
5. Rotate distributor as necessary to align timing
marks. T;ming mark is a steel ball embedded in the
flywheel and a pointer in a window in the right fly-
wheel housing. See Figure lC-4.:Figure lC-4 Ignition Timing Marks
6.
Tightq clamp bolt securely and recheck timing
mark ahgnment.
7. Reconnect vacuum hoses and adjust engine idle
speed
an: mixture.
IGNlTlOFj WIRE INSPECTION
1. The c$il and spark plug wires are of a specialresistance type. These secondary ignition wires
reduce television and radio interference.
2. Wipe ignition wires with a cloth moistened with
solvent and wipe dry. Bend wires to check for brittle,
cracked or swollen insulation. Defective insulation
will permit missing or cross-firing of spark plugs,
therefore any defective wires must be replaced.
3. If wire insulation is in good condition, clean any
terminals that are corroded and replace any termi-
nals that are broken or damaged. Terminals must tit
tight on spark plugs and in distributor cap.
4. Replace any hardened, cracked or loose cap nip-
ples or spark plug boots.
5. Check resistance of each wire from contact inside
distributor cap to spark plug or coil terminal. Re-
place any wire having over 10,000 ohms resistance
reading. See Figure lC-5.
Figure fC-5 Checking Ignition Wire Resistance
CHECK IGNITION OUTPUT
1. Disconnect secondary coil ivire so that engine will
not start. Connect a voltmeter from the battery side
of the coil primary to ground and check voltage
while engine is cranking. Reading should be 10 volts
or more. Low reading could be caused by a defective
battery, a discharged battery, high starter current
draw, a bad connection in the starter circuit or a bad
connection in the primary ignition circuit.
2. Connect an oscilloscope according to manufac-
turer’s instructions. Disconnect coil wire. Crank en-
gine and read coil output voltage. Reading should
exceed 20 KV (20,000 volts).

1 E- 381973 OPEL SERVICE MANUAL
4. Turn switch on to see if wiper niotor will function
with wiper linkage’detached. If wiper motor will ndt
run, disconnect connector at wiper motor and co?-
nect hot lead from battery to terminal No. 53 onwiper motor. If wiper motor runs, the wiper switch
is faulty or there is an break in the lead wire. If wiper
motor still will not run, remove and bench test.
MAJOR REPAIRWIPER TRANSMISSIONS
Removal (1900 and Manta)1. Remove wiper blade (2).
2. Remove the wiper transmission retaining nut,
washer, and rubber seal ring. See .Figure lE-1.
Figure lE-1 Crank Arm Retaining Nut3. Remove instrument cluster housing.
If only left wiper transmission is to be serviced, it can
be done without removing any ‘other instrument
panel components. If the right side, or both, trans-
missions are to be serviced, then
it will be necessary
for complete instrument panel removal. On the Ral-
lye models, the gauge carrier must also be remove&Qn all
1900 and Manta Models the defroster ducts
are secured to the instrument panel cover, by two (‘2)
spring clips, and should not be removed from
dayhcover. Remove cover and duct as, a unit.
4. Remove retaining clips from transmission co;-netting rod pins. Pull connecting rods off pins. See
Item “A”, Figure lE-2.
5. Remove the screws securing the wiper transmis-
sion to the inner side of the cowl (Items “B”, Figuie
13), and remove the transmission assemblies.I
Figure lE-2 Connecting Rod Retaining Clips
Installation1. Place wiper transmissions into position at cowl
and install holding screws.
2. Push connecting rods onto transmission cranking
arm pins and install retaining clips. See Figure lE-2,
Item “A”.
3. Reinstall dash and instrument cluster parts.
4.
1nst:all the rubber seal ring, washer, and transmis-
sion retaining nut. See Figure IE-1.
5. Install wiper blades and check the position of the
blades in the park position. See Figure lE-3.
Figure lE-3 Wiper Blades in Park Position
Removal and Installation of GT W/per Transmission1. Remove nuts and remove both wiper
arms. See
Figure lE-4.
2. Remove three (3) bolts from each windshield