
Back To Article
GENERAL INFORMATION
How To Use The Engine Perform ance Section - 1989 & Newer Models
* PLEASE READ THIS FIRST *
HOW TO USE THE ENGINE PERFORMANCE SECTION
Congratulations, you have purchased the most advanced automotive repair and service information available. This information can help you, as
a professional automotive technician, to maintain top vehicle performance, and correct driveability problems on today's high-tech vehicles.
For your convenience and ease in use, all of our engine performance service and repair information is consistently organized by manufacturer,
using a progressive diagnostic/workflow approach. Due to the differences in how each manufacturer approaches diagnosis and repair, once
started and inside of an article, that manufacturer may drive the workflow in a direction other than what is outlined here.
The progressive diagnostic/workflow of our data is as follows:
APPLICATION to identify vehicle and system usage.
EMISSION APPLICATION to identify emission system usage.
SPECIFICATIONS to quickly find an engine performance service specification.
ADJUSTMENTS to perform engine performance related routine adjustments.
THEORY & OPERATION to familiarize yourself with new systems and technologies.
BASIC DIAGNOSTIC PROCEDURES located under TESTING & DIAGNOSTICS, also referred to as BASIC TESTING, is used for
performing a basic vehicle inspection and is also the starting point for diagnosis of a "no-start" condition.
SELF-DIAGNOSTICS located under TESTING & DIAGNOSTICS, also referred to as TESTS W/CODES, is where manufacturer
specific procedures for retrieving, identifying and diagnosing DTCs (trouble codes) retained in a control modules memory are located.
TROUBLE SHOOTING - NO CODES located under TESTING & DIAGNOSTICS, also referred to as TESTS W/O CODES, is where
an engine performance problem that does not set a DTC can be potentially isolated through either a SYMPTOM or INTERMITTENTS
duplication procedure.
SYSTEM & COMPONENT TESTING located under TESTING & DIAGNOSTICS, also referred to as SYSTEM/COMPONENT
TESTS, once directed to this article, specific system and component tests can be performed to help isolate faulty component/system
prior to replacement.
PIN VOLTAGE CHARTS provide supplemental information to help determine correct control module input and output signals. Pin
charts may also be referred to as PID charts by some manufacturers.
SENSOR RANGE CHARTS help determine if a sensor is out of calibration. In some cases an out-of-calibration sensor will not set a
DTC (trouble code), resulting in difficult to diagnose driveability symptoms.
VACUUM DIAGRAMS help determine correct routing of vacuum hoses when reinstalling components or performing emission
inspections.
REMOVE, OVERHAUL & INSTALL provides procedures necessary for removing and installing engine performance related
components.
WIRING DIAGRAMS can be used to identify circuits, terminals, wire colors and components referenced in testing procedures. NEW
COLOR WIRING DIAGRAMS (system diagrams) provide an easy method of identifying and tracing circuits.
APPLICATION
INTRODUCTION/ENGINE/VIN ID
Here you will find out how to identify an engine by its Vehicle Identification Number (VIN). The manufacturer's MODEL COVERAGE chart
lists each model and engine option, the fuel system, ignition system and engine code. Engine serial number locations are also shown here, as
well as the VIN code breakdown. Using model lookup in conjunction with VIN and engine ID will identify application information necessary
for servicing vehicle and ordering parts.
EMISSION APPLICATIONS
EMISSION APPLICATION TABLES
Here you will find a chart listing what emission control devices apply to each model. This can be helpful when performing government-
required emissions inspections. For quick reference, major emission systems and devices are listed in bold type in the emission table. Sub
components are listed in light type.
SPECIFICATIONS
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
Page 1 of 3 MITCHELL 1 ARTICLE - GENERAL INFORMATION How To Use The Engine Performance Section - 1989 & Newer Models
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

SERVICE & ADJUSTMENT SPECIFICATIONS
If you want a specification quickly, this is the place to look. Instead of hunting through a long article, we've separated out the important
specifications and arranged them into easy-to-use tables in a centralized location. You can find valuable information like spark plug wire
resistance, valve clearance, timing, firing orders, etc.
ADJUSTMENT
ON-VEHICLE ADJUSTMENTS
The ON-VEHICLE ADJUSTMENTS article contains the type of information that was previously thought of as TUNE-UP information.
Procedures for checking and adjusting valves, base ignition timing and idle speed are found in this section. Use this section in conjunction with
SERVICE & ADJUSTMENT SPECIFICATIONS for performing routine maintenance. Also, if you have a driveability problem, ensure all on-
vehicle adjustments are within specification before attempting further diagnosis.
THEORY & OPERATION
This article covers basic THEORY & OPERATION of engine performance-related systems and components. Before diagnosing vehicles or new
systems with which you are not completely familiar, read this article.
TESTING & DIAGNOSTICS
BASIC DIAGNOSTIC PROCEDURES/BASIC TESTING
The procedures listed in this article can help you avoid skipping a simple step early, like checking base timing, which could be costly in both
time and money later. This is also a potential starting point for diagnosis of a "no-start" condition. If all systems check out okay here, proceed
to SELF-DIAGNOSTICS/TESTS W/CODES or TROUBLE SHOOTING - NO CODES/TESTS W/O CODES article.
SELF-DIAGNOSTICS/TESTS W/CODES
Use this information to retrieve and interpret Diagnostic Trouble Codes (DTCs) accessed from the vehicle's self-diagnostic system. Once
information is retrieved, manufacturer diagnostic procedures are given to help pinpoint and repair computer system/component faults. Also
included are steps for clearing trouble codes once these faults are repaired. If there is a driveability symptom with no trouble codes set,
proceed to TROUBLE SHOOTING - NO CODES/TESTS W/O CODES article.
TROUBLE SHOOTING - NO CODES/TESTS W/O CODES
This is where to go when you have a problem that does not set a trouble code. It can help determine cause of problem using driveability
symptoms and intermittent testing procedures. Procedures in this information should lead you to a specific component or system test.
SYSTEM & COMPONENT TESTING
Here you will find various tests for engine performance systems and their components, such as air induction (turbochargers and superchargers),
fuel control, ignition control and emission systems.
PIN VOLTAGE CHARTS
These are supplied (when available from manufacturer) to quicken the diagnostic process. By checking pin voltages at the Powertrain Control
Module (PCM), you can determine if the PCM is receiving and/or transmitting proper voltage signals. Pin charts may also be referred to as PID
charts by some manufacturers.
SENSOR RANGE CHARTS
SENSOR OPERATING RANGE CHARTS
These are supplied (when available from manufacturer) to determine if a sensor is out of calibration. An out-of-calibration sensor may not set a
trouble code, but it may cause driveability problems.
VACUUM DIAGRAMS
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
Page 2 of 3 MITCHELL 1 ARTICLE - GENERAL INFORMATION How To Use The Engine Performance Section - 1989 & Newer Models
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

Here we give you underhood views or schematics of vacuum-hose routing which can help you find incorrectly routed hoses. Remember, a
vacuum leak or incorrectly routed vacuum hose on computer-controlled vehicle can cause many driveability problems.
REMOVAL, OVERHAUL & INSTALLATION
After you've diagnosed the problem, this is where to go for the nuts-and-bolts of the job. Here you'll find procedures and specifications for
removing, overhauling (if available) and installing components.
WIRING DIAGRAMS - ENGINE PERFORMANCE
2002 & EARLIER
On 2002 and earlier models, once ENGINE PERFORMANCE is selected as the service category, the expanded menu will display a WIRING
DIAGRAMS - ENGINE PERFORMANCE heading. Once the wiring diagrams article is selected, select the engine performance wiring
diagrams for your lookup model.
2003 & LATER
On models newer than 2002, we have moved all wiring diagrams under a centralized first level model-specific lookup titled WIRING
DIAGRAMS-ALL. When selected, SYSTEM WIRING DIAGRAMS article will display in the center panel. This article contains all available
wiring diagrams related to the selected vehicle. These same wiring diagrams can also be found under the ELECTRICAL/WIRING DIAGRAMS
heading. NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
NOTE:System Wiring diagram s for have been enhanced to include COLORS. T his will enable you to m ore
easily trace a circuit from its source to its destination, without losing your circuit due to parallel or
intersecting lines. Using these diagram s, you can easily identify and trace com ponent circuits, to help
locate shorts and opens in circuits. T hese diagram s can also help you understand how individual
circuits function within a system .
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00002340
Page 3 of 3 MITCHELL 1 ARTICLE - GENERAL INFORMATION How To Use The Engine Performance Section - 1989 & Newer Models
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

Fig. 4: Determining Caster Angle
TOE-IN ADJUSTMENT
Toe-in is the width measured at the rear of the tires subtracted by the width measured at the front of the tires at about spindle height. A
positive figure would indicate toe-in and a negative figure would indicate toe-out. If the distance between the front and rear of the tires is the
same, toe measurement would be zero. To adjust:
1) Measure toe-in with front wheels in straight ahead position and steering wheel centered. To adjust toe-in, loosen clamps and turn adjusting
sleeve or adjustable end on right and left tie rods. See Fig. 2
and Fig. 5 .
2) Turn equally and in opposite directions to maintain steering wheel in centered position. Face of tie rod end must be parallel with machined
surface of steering rod end to prevent binding.
3) When tightening clamps, make certain that clamp bolts are positioned so there will be no interference with other parts throughout the entire
travel of linkage.
Fig. 5: Wheel Toe
-In (Dimension A Less Dimension B)
TOE-OUT ON TURNS
1. Toe-out on turns (turning radius) is a check for bent or damaged parts, and not a service adjustment. With caster, camber, and toe-in
properly adjusted, check toe-out with weight of vehicle on wheels.
2. Use a full floating turntable under each wheel, repeating test with each wheel positioned for right and left turns. Incorrect toe-out
generally indicates a bent steering arm. Replace arm, if necessary, and recheck wheel alignment.
Page 3 of 4 MITCHELL 1 ARTICLE - GENERAL INFORMATION Wheel Alignment Theory & Operation
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

STEERING AXIS INCLINATION
1. Steering axis inclination is a check for bent or damaged parts, and not a service adjustment. Vehicle must be level and camber should be
properly adjusted. See Fig. 6
.
2. If camber cannot be brought within limits and steering axis inclination is correct, steering knuckle is bent. If camber and steering axis
inclination are both incorrect by approximately the same amount, the upper and lower control arms are bent.
Fig. 6: Checking Steering Axis Inclination
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00060716
Page 4 of 4 MITCHELL 1 ARTICLE - GENERAL INFORMATION Wheel Alignment Theory & Operation
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

Back To Article
1991 GENERAL SERVICING
A/C Com pressor Refrigerant Oil Checking
ISOLATING COMPRESSOR
1. Connect service gauge set to the compressor service valves and open compressor valves slightly (turn in clockwise). Start engine and
operate air conditioning. Slowly turn compressor suction valve clockwise toward closed (front-seated) position.
2. When suction pressure is reduced to zero or less, turn off engine and compressor and quickly turn suction valve stem in to full front-
seated position. Suction pressure should be slightly above zero. Turn discharge valve into front-seated position.
3. To check oil level, slowly open compressor crankcase plug to relieve any remaining pressure. After oil level is corrected, cap service
gauge ports on both valves. Back-seat suction service valve to allow refrigerant to enter compressor. Open discharge valve halfway.
4. Loosen discharge service valve cap, allowing refrigerant pressure to force air out of compressor. Back-seat service valve and tighten cap.
Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used in the air conditioning system. This oil is highly refined and dehydrated to a point
where moisture content is less than 10 parts per million. The oil container must be tightly closed at all times when not in use, or moisture will
be absorbed into the refrigerant oil from the air.
SERVICING PRECAUTIONS
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be isolated and removed without discharging entire system. See ISOLATING
COMPRESSOR at the beginning of this article. Otherwise, discharge system completely before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all fittings to be opened. Always use 2 wrenches when tightening or loosening fittings
to avoid twisting or distorting lines. Cap or plug all openings as soon as lines are removed. DO NOT remove caps until immediately before
connections are made. This will keep entry of air and moisture to a minimum.
CONNECTING LINES AND FITTINGS
A new gasket or "O" ring should be used in all instances when connecting lines or fittings. Dip "O" ring in new refrigerant oil and ensure it is
not twisted during installation. Always use 2 wrenches to prevent damage to lines and fittings.
PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and all connections have been made, evacuate system thoroughly with a vacuum
pump. Charge system with proper amount of refrigerant and perform a leak test. See REFRIGERANT OIL & R-12 SPECIFICATIONS chart in
this section for system capacities. Be sure to check all fittings that have been opened. After system has been leak tested, make a system
performance check.
ATSUGI ROTARY VANE DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine, discharge refrigerant and remove compressor from vehicle. See SERVICING PRECAUTIONS at beginning of article. Drain
compressor oil from compressor discharge port and measure the amount. Oil is sometimes hard to drain when compressor is cool.
Remove oil while compressor is warm.
3. If the amount drained is less than 3 ounces, conduct leak tests at system connections, and if necessary, repair or replace faulty parts.
Check purity of oil and adjust oil level as follows.
4. If amount drained was above 3 ounces, oil level is right. Pour in same amount as was drained. If amount drained was below 3 ounces,
pour in 3 ounces of new refrigerant oil.
BOSCH 6-CYL DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine and discharge refrigerant. Remove refrigerant oil level inspection plug on side of compressor. Oil should be at lower lip of
threaded hole. Add necessary new refrigerant oil (if low). Replace inspection plug and tighten to 10-12 ft. lbs. (14-16 N.m). NOTE:Only com pressors with stem -type service valves can be isolated.
NOTE:Recent findings by the EPA indicate that refrigerant is harm ful to the earth's protective Ozone layer.
When discharging refrigerant, DO NOT allow refrigerant to enter the atm osphere. If available, use
refrigerant recovery/recycle system s when discharging system . Always follow m anufacturer's
instructions.
NOTE:Air conditioning system s will not norm ally need addition of refrigerant oil unless definite oil loss has
occurred due to ruptured lines, leaking com pressor seals, com pressor overhaul or com ponent
replacem ent.
Page 1 of 4 MITCHELL 1 ARTICLE - 1991 GENERAL SERVICING A/C Compressor Refrigerant Oil Checking
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

Back To Article
A/C COMPRESSOR SERVICING
1991 GENERAL SERVICING Com pressor Service
ISOLATING COMPRESSOR
1. Connect service gauge set to the compressor service valves and open compressor valves slightly (turn in clockwise). Start engine and
operate air conditioning. Slowly turn compressor suction valve clockwise toward closed (front-seated) position.
2. When suction pressure is reduced to zero or less, turn off engine and compressor and quickly turn suction valve stem in to full front-
seated position. Suction pressure should be slightly above zero. Turn discharge valve into front-seated position.
3. To check oil level, slowly open compressor crankcase plug to relieve any remaining pressure. After oil level is corrected, cap service
gauge ports on both valves. Back-seat suction service valve to allow refrigerant to enter compressor. Open discharge valve halfway.
4. Loosen discharge service valve cap, allowing refrigerant pressure to force air out of compressor. Back-seat service valve and tighten cap.
Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used in the air conditioning system. This oil is highly refined and dehydrated to a point
where moisture content is less than 10 parts per million. The oil container must be tightly closed at all times when not in use, or moisture will
be absorbed into the refrigerant oil from the air.
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be isolated and removed without discharging entire system. Otherwise, discharge system
completely using approved refrigerant recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all fittings to be opened. Always use 2 wrenches when tightening or loosening fittings
to avoid twisting or distorting lines. Cap or plug all openings as soon as lines are removed. Do not remove caps until immediately before
connections are made. This will keep entry of air and moisture to a minimum.
CONNECTING LINES AND FITTINGS
A new gasket or "O" ring should be used in all instances when connecting lines or fittings. Dip "O" ring in new refrigerant oil and ensure it is
not twisted during installation. Always use 2 wrenches to prevent damage to lines and fittings.
PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and all connections have been made, evacuate system thoroughly with a vacuum
pump. Charge system with proper amount of refrigerant and perform a leak test. See REFRIGERANT OIL & R-12 SPECIFICATIONS chart in
this section for system capacities. Be sure to check all fittings that have been opened. After system has been leak tested, make a system
performance check.
ATSUGI ROTARY VANE CLUTCH R & I
Removal
When replacing compressor clutch, be careful not to scratch shaft or bend pulley. When removing center bolt, hold clutch disc with Clutch
Holder (KV99231010). Using Hub Puller (KV998VR001 & KV99231010), remove clutch disc. When removing pulley, remove lock nut with
Hub Socket (KV99235160).
Installation
Wipe oil off clutch surface. Adjust disc pulley clearance to .012-.024" (.3-.6 mm). Tighten center bolt to 80-104 INCH lbs. (9.1-11.8 N.m).
Tighten clutch lock nut to 22-29 ft. lbs. (29-39 N.m). See Fig. 1
. CAUT ION: When discharging air conditioning system , use only approved refrigerant recovery/recycling
equipm ent. Make every attem pt to avoid discharging refrigerant into the atm osphere.
NOTE:Only com pressors with stem -type service valves can be isolated.
CAUT ION: When discharging air conditioning system , use only approved refrigerant recovery/recycling
equipm ent. Make every attem pt to avoid discharging refrigerant into the atm osphere.
NOTE:Air conditioning system s will not norm ally need addition of refrigerant oil unless definite oil loss has
occurred due to ruptured lines, leaking com pressor seals, com pressor overhaul or com ponent
replacem ent.
Page 1 of 18 MITCHELL 1 ARTICLE - A/C COMPRESSOR SERVICING 1991 GENERAL SERVICING Compressor Service
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...

Fig. 1: Atsugi Rotary Vane Compressor
Courtesy of NISSAN MOTOR CO., U.S.A.
BOSCH 6-CYL CLUTCH R & I
Removal
1. Hold clutch plate and remove shaft nut. Using Clutch Plate Remover (64 5 00), remove clutch plate. Using snap ring pliers, remo ve
circlip and remove pulley assembly.
2. If pulley bearing is being replaced, remove circlip at rear of pulley. Press bearing and spacer from pulley. Press in new bearing with
spacer and replace circlip.
Installation
1. Clean all surfaces. Install pulley assembly on compressor and install circlip. Ensure clutch plate shim is in place on shaft. Install clutch
plate and nut. Tighten nut to 13-14 ft. lbs. (18-20 N.m).
2. Using a feeler gauge, check clutch plate-to-pulley clearance. Clearance should be .028-.051" (.7-1.3 mm). If clearance is not correct,
remove clutch plate and replace clutch plate shim. See Fig. 2
.
BOSCH 6-CYL SHAFT SEAL R & I
Removal & Installation
1. Remove clutch plate. Remove shaft key and circlip. Using Seal Seat Remover/Installer (64 5 030), remove seal seat.
2. Using Seal Remover/Installer (64 5 040), remove shaft seal by turning seal slightly clockwise to disengage tangs and pull out shaft seal.
Remo ve "O" rin g seal .
3. Coat new "O" ring seal with refrigerant oil and install. Coat new shaft seal with refrigerant oil and install shaft seal on Seal
Remover/Installer (64 5 040). Ensure alignment of shaft seal and shaft machine surfaces. Insert shaft seal and turn slightly
counterclockwise to secure on shaft.
4. Using sleeve from Seal Seat Remover/Installer (64 5 030), push seal seat into compressor and install circlip. Install shaft key and clutch
plate. Check compressor oil level before charging system.
Page 2 of 18 MITCHELL 1 ARTICLE - A/C COMPRESSOR SERVICING 1991 GENERAL SERVICING Compressor Service
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
...