
Fig. 4: Ignition Primary Trouble Shooting Chart
STARTER TROUBLE SHOOTING
BASIC STARTER TROUBLE SHOOTING CHART
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
CONDITION & POSSIBLE CAUSECORRECTION
Starter Fails to Operate
Dead battery or bad connections between starter and batteryCheck battery charge and all
wires and connections to
starter
Ignition switch faulty or misadjustedAdjust or replace ignition
switch
Open circuit between starter switch ignition terminal on starter relayCheck and repair wires and
connections as necessary
Starter relay or starter defectiveSee Testing in STARTER
article
Open solenoid pull-in wireSee Testing in STARTER
article
Starter Does Not Operate and Headlights Dim
Weak battery or dead cellCharge or replace battery as
necessary
Loose or corroded battery connectionsCheck that battery
connections are clean and
tight
Internal ground in starter windingsSee Testing in STARTER
article
Grounded starter fieldsSee Testing in STARTERS
Armature rubbing on pole shoesSee STARTER article
Page 19 of 36 MITCHELL 1 ARTICLE - GENERAL INFORMATION Trouble Shooting - Basic Procedures
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carburetor. As the exhaust gas quickly warms the intake mixture, distribution is improved. This results in better cold engine driveability,
shorter choke periods and lower emissions.
Ensure EFE valve in exhaust manifold is not frozen or rusted in a fixed position. On vacuum-actuated EFE system, check EFE thermal vacuu
m
valve and check valve(s). Also check for proper vacuum hose routing. See Fig. 19
.
Fig. 19: Typical Vacuum
-Actuated EFE System
Courtesy of GENERAL MOTORS CORP.
EMISSION MAINTENANCE REMINDER LIGHT (EMR)
If equipped, the EMR light (some models may use a reminder flag) reminds vehicle operator that an emission system maintenance is required.
This indicator is activated after a predetermined time/mileage.
When performing a smog check inspection, ensure EMR indicator is not activated. On models using an EMR light, light should glow when
ignition switch is turned to ON position and should turn off when engine is running.
If an EMR flag is present or an EMR light stays on with engine running, fail vehicle and service or replace applicable emission-related
components. To reset an EMR indicator, refer to appropriate MAINTENANCE REMINDER LIGHTS article in GENERAL INFORMATION.
MALFUNCTION INDICATOR LIGHT (MIL)
The Malfunction Indicator Light (MIL) is used to alert vehicle operator that the computerized engine control system has detected a
malfunction (when it stays on all the time with engine running). On some models, the MIL may also be used to display trouble codes.
As a bulb and system check, malfunction indicator light will glow when ignition switch is turned to ON position and engine is not running.
When engine is started, light should go out.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00130226
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GENERAL INFORMATION
Parasitic Load Explanation & T est Procedures
* PLEASE READ THIS FIRST *
GENERAL INFORMATION
The term Parasitic Load refers to electrical devices that continue to use or draw current after the ignition switch is turned to OFF position. This
small amount of continuous battery draw is expressed in milliamps (mA). On Chrysler vehicles, a typical Parasitic Load should be no more
than 30 milliamps (0.030 amps). On Ford Motor Co. and General Motors vehicles produced after 1980, a typical Parasitic Load should be no
more than 50 milliamps (0.050 amps).
Vehicles produced since 1980 have memory devices that draw current with ignition off for as long as 20 minutes before shutting down the
Parasitic Drain. When Parasitic Load exceeds normal specifications, the vehicle may exhibit dead battery and no-start condition.
Follow test procedure for checking Parasitic Loads to completion. A brief overview of a suggested test procedure is included along with some
typical Parasitic Load specifications. Refer to GENERAL MOTORS PARASITIC LOAD TABLE chart.
TESTING FOR PARASITIC LOAD
The battery circuit must be opened to connect test switch (shunt) and ammeter into the circuit. When a battery cable is removed, timer circuits
within the vehicle computer are interrupted and immediately begin to discharge. If in doubt about the condition of the ammeter fuse, test it
with an ohmmeter prior to beginning test. An open fuse will show the same reading (00.00) as no parasitic drain. Begin test sequence with the
meter installed and on the 10-amp scale. Select lower scale to read parasitic draw.
CHRYSLER IGNITION OFF DRAW (IOD) TEST
To test for excessive IOD, verify that all electrical accessories are OFF. Turn off all lights, remove ignition key, and close all doors and decklid.
If the vehicle is equipped with electronic accessories (illuminated entry, automatic load leveler, body computer, or high line radio), allow the
system to automatically shut off (time out), up to 3 minutes.
1. Raise the hood and disconnect both battery cables, negative first.
2. Reconnect the negative cable and connect a typical 12-volt test light (low wattage bulb) between the positive cable clamp and the
positive battery post. Remove the engine compartment lamp bulb. If the test light does not light, proceed to step 3
. If the test light does
light, proceed to step, 4
. The test light will indicate IOD greater than 3 amps. After higher amperage IOD has been corrected, proceed to
step 3
.
3. ith 12-volt test light still connected (not lit), connect an ammeter (milliampere scale) between the positive cable clamp and the positive
battery post, disconnect test light, refer to instructions provided with ammeter being used. A reading of 30 milliamperes or less indicates
normal electrical draw. If ammeter reads more than 30 milliamperes, excessive IOD must be corrected.
4. Locate the fuse panel and remove fuses or circuit breakers one at a time, and observe ammeter after each fuse or circuit breaker is
removed. If test light goes out and the reading drops below 30 milliamperes when a certain fuse or circuit breaker is removed, that circuit
may have a defect.
5. If IOD is detected after all fuses and circuit breakers have been removed, disconnect the 60-way connector at the Single Module Engine
Control (SMEC), located outboard of the battery.
6. If excessive IOD is detected after all fused circuits and SMEC have been verified, disconnect the B+ terminal from the alternat o r. If
reading drops below 30 milliamperes, reinstall all fuses and circuit breakers, reconnect B+ terminal at alternator, reconnect battery, and
perform alternator diagnostics.
7. Install engine compartment lamp bulb.
TEST PROCEDURE USING TEST SWITCH
1. Turn ignition off. Remove negative battery terminal cable. Install Disconnect Tool (J-38758) test switch male end to negative battery
cable. Turn test switch knob to OFF position (current through meter). Install negative battery cable to the female end of test switch. NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
CAUT ION: Always turn ignition off when connecting or disconnecting battery cables, battery chargers or jum per
cables. DO NOT turn test switch to OFF position (which causes current to run through am m eter or
vehicle electrical system ).
NOTE:Mem ory functions of various accessories m ust be reset after the battery is reconnected.
CAUT ION: IOD greater than 3 am ps m ay dam age m illam pm eter.
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2. Turn test switch knob to ON position (current through switch). Road test vehicle with vehicle accessories on (radio, air conditioner, etc).
After road test, turn ignition switch to LOCKED position and remove key. Connect ammeter terminals to test switch terminals. See Fig.
1. Select 10-amp scale.
3. Turn off all electrical accessories. Turn off interior lights, underhood lamp, trunk light, illuminated entry, etc. To avoid damaging
ammeter or obtaining a false meter reading, all accessories must be off before turning test switch knob to OFF position.
4. Turn test switch knob to OFF position to allow current to flow through ammeter. If meter reads wrong polarity, turn test switch to ON
position and reverse leads. Turn test switch to OFF position. Observe current reading. If reading is less than 2 amps, turn test switch to
ON position to keep electrical circuits powered-up.
5. Select low amp scale. Switch lead to the correct meter position. Turn test switch to OFF position and compare results to normal current
draw. See GENERAL MOTORS PARASITIC LOAD TABLE (MILLIAMPS)
. If current draw is unusually high for the vehicle's
overall electrical system, remove system fuses one at a time until current draw returns to normal.
6. Turn test switch to ON position each time door is opened or fuse is removed. Turn switch to OFF position to read current draw va l u e
through meter. When the cause of excessive current drain has been located and repaired, remove test switch and reconnect negative
battery cable to the negative battery terminal.
INTERMITTENT PARASITIC LOAD PROBLEMS
Intermittent parasitic load can occur because of a memory device that does not power down with ignition off. With an intermittent parasitic
load, battery draw can be greater than 1.0 amp.
To find an intermittent problem requires that an ammeter and Disconnect Tool (J-38758) test switch be connected and left in the circuit. See
Fig. 1
. Road test vehicle. After road test, turn ignition off and remove key.
Monitor the milliamps scale for 15-20 minutes after ignition is turned off. This allows monitoring memory devices to determine if they time out
and stop drawing memory current. The test switch is needed to protect ammeter when the vehicle is started.
Fig. 1: Connecting Kent
-Moore Disconnect Tool (J-38758)
Courtesy of GENERAL MOTORS CORP.
GENERAL MOTORS PARASITIC LOAD
ComponentNormal DrawMaximum DrawTime-Out (Minutes)
Anti-Theft System0.41.0.....
Auto Door Lock1.01.0.....
Body Control Module3.612.420
Central Processing System1.62.720
Electronic Control Module5.610.0.....
Electronic Level Control2.03.320
Heated Windshield Module0.30.4.....
HVAC Power Module1.01.0.....
Illuminated Entry1.01.01
Light Control Module0.51.0.....
Oil Level Module0.10.1.....
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GENERAL INFORMATION
Waveform s - Injector Pattern T utorial
* PLEASE READ THIS FIRST *
PURPOSE OF THIS ARTICLE
Learning how to interpret injector drive patterns from a Lab Scope can be like learning ignition patterns all over again. This article exists to
ease you into becoming a skilled injector pattern interpreter.
You will learn:
How a DVOM and noid light fall short of a lab scope.
The two types of injector driver circuits, voltage controlled & current controlled.
The two ways injector circuits can be wired, constant ground/switched power & constant power/switched ground.
The two different pattern types you can use to diagnose with, voltage & current.
All the valuable details injector patterns can reveal.
SCOPE OF THIS ARTICLE
This is NOT a manufacturer specific article. All different types of systems are covered here, regardless of the specific year/make/model/engine.
The reason for such broad coverage is because there are only a few basic ways to operate a solenoid-type injector. By understanding the
fundamental principles, you will understand all the major points of injector patterns you encounter. Of course there are minor differences in
each specific system, but that is where a waveform library helps out.
If this is confusing, consider a secondary ignition pattern. Even though there are many different implementations, each still has a primary
voltage turn-on, firing line, spark line, etc.
If specific waveforms are available in On Demand for the engine and vehicle you are working on, you will find them in the Engine Performance
section under the Engine Performance category.
IS A LAB SCOPE NECESSARY?
INTRODUCTION
You probably have several tools at your disposal to diagnose injector circuits. But you might have questioned "Is a lab scope necessary to do a
thorough job, or will a set of noid lights and a multifunction DVOM do just as well?"
In the following text, we are going to look at what noid lights and DVOMs do best, do not do very well, and when they can mislead you. As
you might suspect, the lab scope, with its ability to look inside an active circuit, comes to the rescue by answering for the deficiencies of these
other tools.
OVERVIEW OF NOID LIGHT
The noid light is an excellent "quick and dirty" tool. It can usually be hooked to a fuel injector harness fast and the flashing l igh t is e a sy t o
understand. It is a dependable way to identify a no-pulse situation.
However, a noid light can be very deceptive in two cases:
If the wrong one is used for the circuit being tested. Beware: Just because a connector on a noid light fits the harness does not mean it is
the right one.
If an injector driver is weak or a minor voltage drop is present.
Use the Right Noid Light
In the following text we will look at what can happen if the wrong noid light is used, why there are different types of noid lights (besides
differences with connectors), how to identify the types of noid lights, and how to know the right type to use.
First, let's discuss what can happen if the incorrect type of noid light is used. You might see:
A dimly flashing light when it should be normal.
A normal flashing light when it should be dim.
A noid light will flash dim if used on a lower voltage circuit than it was designed for. A normally operating circuit would appear
underpowered, which could be misinterpreted as the cause of a fuel starvation problem.
Here are the two circuit types that could cause this problem: NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
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Circuits with external injector resistors. Used predominately on some Asian & European systems, they are used to reduce the available
voltage to an injector in order to limit the current flow. This lower voltage can cause a dim flash on a noid light designed for full voltage.
Circuits with current controlled injector drivers (e.g. "Peak and Hold"). Basically, this type of driver allows a quick burst of
voltage/current to flow and then throttles it back significantly for the remainder of the pulse width duration. If a noid light was designed
for the other type of driver (voltage controlled, e.g. "Saturated"), it will appear dim because it is expecting full voltage/current to flow
for the entire duration of the pulse width.
Let's move to the other situation where a noid light flashes normally when it should be dim. This could occur if a more sensitive n o id l igh t is
used on a higher voltage/amperage circuit that was weakened enough to cause problems (but not outright broken). A circuit with an actual
problem would thus appear normal.
Let's look at why. A noid light does not come close to consuming as much amperage as an injector solenoid. If there is a partial driver failure
or a minor voltage drop in the injector circuit, there can be adequate amperage to fully operate the noid light BUT NOT ENOUGH TO
OPERATE THE INJECTOR.
If this is not clear, picture a battery with a lot of corrosion on the terminals. Say there is enough corrosion that the starter motor will not
operate; it only clicks. Now imagine turning on the headlights (with the ignition in the RUN position). You find they light normally and are
fully bright. This is the same idea as noid light: There is a problem, but enough amp flow exists to operate the headlights ("noid light"), but not
the starter motor ("injector").
How do you identify and avoid all these situations? By using the correct type of noid light. This requires that you understanding the types of
injector circuits that your noid lights are designed for. There are three. They are:
Systems with a voltage controlled injector driver. Another way to say it: The noid light is designed for a circuit with a "high" resistance
injector (generally 12 ohms or above).
Systems with a current controlled injector driver. Another way to say it: The noid light is designed for a circuit with a low resistance
injector (generally less than 12 ohms) without an external injector resistor.
Systems with a voltage controlled injector driver and an external injector resistor. Another way of saying it: The noid light is designed
for a circuit with a low resistance injector (generally less than 12 ohms) and an external injector resistor.
If you are not sure which type of circuit your noid light is designed for, plug it into a known good car and check out the results. If it flashes
normally during cranking, determine the circuit type by finding out injector resistance and if an external injector resistor is used. You now
know enough to identify the type of injector circuit. Label the noid light appropriately.
Next time you need to use a noid light for diagnosis, determine what type of injector circuit you are dealing with and select the appropriate
noid light.
Of course, if you suspect a no-pulse condition you could plug in any one whose connector fit without fear of misdiagnosis. This is because it is
unimportant if the flashing light is dim or bright. It is only important that it flashes.
In any cases of doubt regarding the use of a noid light, a lab scope will overcome all inherent weaknesses.
OVERVIEW OF DVOM
A DVOM is typically used to check injector resistance and available voltage at the injector. Some techs also use it check injector on-time
either with a built-in feature or by using the dwell/duty function.
There are situations where the DVOM performs these checks dependably, and other situations where it can deceive you. It is important to be
aware of these strengths and weaknesses. We will cover the topics above in the following text.
Checking Injector Resistance
If a short in an injector coil winding is constant, an ohmmeter will accurately identify the lower resistance. The same is true with an open
winding. Unfortunately, an intermittent short is an exception. A faulty injector with an intermittent short will show "good" if the ohmmeter
cannot force the short to occur during testing.
Alcohol in fuel typically causes an intermittent short, happening only when the injector coil is hot and loaded by a current high e n o u gh t o
jump the air gap between two bare windings or to break down any oxides that may have formed between them.
When you measure resistance with an ohmmeter, you are only applying a small current of a few milliamps. This is nowhere near enough to
load the coil sufficiently to detect most problems. As a result, most resistance checks identify intermittently shorted injectors as being normal.
There are two methods to get around this limitation. The first is to purchase an tool that checks injector coil windings under full load. The
Kent-Moore J-39021 is such a tool, though there are others. The Kent-Moore costs around $240 at the time of this writing and works on many
different manufacturer's systems.
The second method is to use a lab scope. Remember, a lab scope allows you to see the regular operation of a circuit in real time. If an injector
is having an short or intermittent short, the lab scope will show it.
Checking Available Voltage At the Injector
Verifying a fuel injector has the proper voltage to operate correctly is good diagnostic technique. Finding an open circuit on the feed circuit
like a broken wire or connector is an accurate check with a DVOM. Unfortunately, finding an intermittent or excessive resistance problem with
a DVOM is unreliable.
Let's explore this drawback. Remember that a voltage drop due to excessive resistance will only occur when a circuit is operating? Since the
injector circuit is only operating for a few milliseconds at a time, a DVOM will only see a potential fault for a few milliseconds. The remaining
90+% of the time the unloaded injector circuit will show normal battery voltage. NOTE:Som e noid lights can m eet both the second and third categories sim ultaneously.
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Fig. 6: Identification Label Locations
Courtesy of FORD MOTOR CO.
SERVICE LABOR TIMES
WHEEL & TIRE SPECIFICATIONS
TIRE INFLATION
Tire inflation pressure is listed on a decal attached to right door pillar.
WHEEL TIGHTENING
Tighten wheel lug bolts to 65-87 ft. lbs. (88-118 N.m). If wheels are equipped with locking type lug nuts, ALWAYS position the "keyed" nut
opposite the valve stem.
BATTERY SPECIFICATIONS
All 1988-92 models use a BX-35 battery. The 1993 Festiva uses a 50D 20L standard battery.
CAUTIONS & WARNINGS
BATTERY WARNING
REPLACING BLOWN FUSES
NOTE:For 1990 and newer vehicles, labor tim es are provided, where available, within appropriate SERVICE
INT ERVAL table in SCHEDULED SERVICES article.
CAUT ION: When battery is disconnected, vehicles equipped with com puters m ay lose m em ory data. When battery
power is restored, driveability problem s m ay exist on som e vehicles. T hese vehicles m ay require a
relearn procedure. See COMPUT ER RELEARN PROCEDURES article in the GENERAL INFORMAT ION
section.
WARNING:When battery is disconnected, vehicles equipped with com puters m ay lose m em ory data. When battery
power is restored, driveability problem s m ay exist on som e vehicles. T hese vehicles m ay require a
relearn procedure. See COMPUT ER RELEARN PROCEDURES article in GENERAL INFORMAT ION
section.
CAUT ION: Before replacing a blown fuse, rem ove ignition key, turn off all lights and accessories to avoid
dam aging the electrical system . Be sure to use fuse with the correct indicated am perage rating. T he use
of an incorrect am perage rating fuse m ay result in a dangerous electrical system overload.
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Fig. 7: Fuse Panel Identification
Courtesy of FORD MOTOR CO.
Fuse Identification
1 - 15 Amp License Plate Light, Rear Side Marker Light, Front Parking Lights, Cluster and Tail Lights
2 - 15 Amp Horn, Brakelights, High-Mount Brakelight
3 - 15 Amp (1988-89) Safety Belt Warning, Turn & Hazard Warning Flasher Lights, Radio, Trunk Light, Ignition Key Reminder Buzzer
15 Amp (1990-93) Safety Belt Warning, Turn & Hazard Warning Flasher Lights, Ignition Key Reminder Buzzer
4 - 15 Amp Audio System, Cigarette Lighter, Remote Control Mirror
5 - 15 Amp Rear Wiper/Washer, Daytime Running Light System (Canada)
6 - 15 Amp Heater & Air Conditioner
7 - 20 Amp Heater & Air Conditioner, Cooling Fan System
8 - 10 Amp (1988-89) Interior Courtesy Lights
10 Amp (1990-93) R a d io , In t e r io r C o u r t e sy Ligh t s, Lu gga ge C o mp a r t me n t Ligh t
9 - 15 Amp (1988-89) Front Wiper/Washer
15 Amp (1990-93) Front Wiper/Washer, Shift-Lock System (ATX), Engine Control System
10 - 10 Amp Charging System, Emission Control System
11 - 10 Amp (1988-90) Safety Belt Warning, Turn & Hazard Warning Flasher Lights, Back-Up Lights, Instrument Cluster, Warning
Lights,
10 Amp (1991-93) Safety Belt Warning, Turn & Hazard Warning Flasher Lights, Back-Up Lights, Instrument Cluster, Warning Lights,
Shift-Lock System
12 - 15 Amp Rear Window Defroster
13 - Not Used (1988-89) Spare
30 Amp (1990-93) Passive Restraint System (Automatic Seat Belt)
In-Line Fuse Identification
15 Amp (1990-93) Condenser Fan Motor (A/T Models Only)
10 Amp (1990-93) A/C System (located on left side of heater case)
FUSIBLE LINK BLOCK IDENTIFICATION
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