Fuel Pump Service

May/June2009 Volume 16, No. 3 (TS-PU-0008-09)
Fuel Pump Service
Ever since it was discovered during WWI that
adding tetraethyl lead to gasoline significantly
increased its octane rating (typical mid-1920s
gasolines had a 40–60 octane rating), more
and more additives have been added to gasoline during the refining process to improve the
fuel’s performance, emissions and economy.
Common additives in gasoline today include:
detergents, corrosion inhibitors, anti-icers, demulsifiers (to break up water particles), deposit
controls (to prevent carbon buildup), antioxidants
(to prevent gum formation) and metal deactivators
(to inhibit oxidation and gum formation catalyzed by
certain metals, especially copper).
Fuel changes to meet tighter emission standards have
lead to the use of oxygenated fuels such as ethanol,
methanol, ETBE and MTBE. In the past, alcohols and
ethers were used primarily as octane enhancers. Now,
the focus is on emissions reduction. Gasoline additives are
regulated to ensure that the finished fuel will not contribute
to fuel system failure. Additive breakdown or excessive
amounts of additives in gasoline can result in fuel system
contamination and lead to pump failure. In fact, fuel contamination is the main cause
of electric fuel pump failure by clogging the pickup strainer or inlet filter as well as
causing internal pump damage.
Diagnosis
During fuel pump diagnosis, keep in mind these key items:
• Start with the basics
– Is fuel pressure within specifications? (check the Service Information)
– Does the fuel pressure hold with the key off? (if applicable)
– On return systems with a vacuum operated regulator, does the fuel pressure
increase during acceleration?
– Has the in-line fuel filter been changed? (if applicable)
• Measure amperage
– If amperage is low, it may be due to bad connections
– If amperage is high, check for possible restrictions or a bad fuel pump
• If a burned, loose terminal is connected to a new fuel pump connector, the new
fuel pump will be ruined
• Use the illustrated pigtail search feature on www.acdelcotechconnect.com when
replacing a fuel pump connector
• Low fuel level in the fuel tank can shorten fuel pump life. Inform the customer
that fuel level affects the life of the fuel pump (gasoline is used for both cooling
and lubrication), and fuel with an octane rating specified in the vehicle owner
manual should be used.
continued on page 2
1
IN THIS ISSUE
Fuel Pump Service . . . . . . . . . . . . . . . . . . . .1
Cool Technology Covered
in Latest A/C Seminar . . . . . . . . . . . . . . . . . .3
A/C Compressor Service Tips . . . . . . . . . . .3
Overlooked Maintenance Items:
Wipers and More . . . . . . . . . . . . . . . . . . . . .4
Improper Use of Conductance Testing
on New Batteries . . . . . . . . . . . . . . . . . . . . .4
Labor Times Now Available on WIP . . . . .5
Expanded Wiring Sockets
and Pigtails Search Tool . . . . . . . . . . . . . . .5
GM New Vehicle Supplier Discount . . . . .6
TSS Q&A . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Tech Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Training Update . . . . . . . . . . . . . . . . . . . . . . .8
Readers Show Off Their Rides . . . . . . . . . .8
ON THE WEB
– www.acdelcotechconnect.com, click on
the TechConnect Magazine link, or
– Log on to the ACDelco LMS, click on the
Resources link
Fuel Pump Service –
continued from page 1
• Check for fuel contamination. It’s
the number one reason for fuel
pump failure. Dirty fuel, additive
breakdown, rust and fuel tank
delamination all work to
clog the fuel pump strainer and
cause premature pump failure.
Pump Replacement
When proper diagnosis leads to the
need to replace the fuel pump, be sure
to follow these guidelines:
• Check for contamination
and flush the fuel tank
– Clean the top of the
fuel tank before removing the fuel pump
– Use hot water
– Install a new in-line
filter and sock filter
fuel pump performance and durability.
During service, technicians will notice
some differences between the MRA and
the fuel pump being replaced.
All hybrid MRAs have the latest fuel
level sensor technology to reduce failures due to worn fingers on the sensor
wiper arm, sulfur contamination, wire
wound sensors and lead sensor kits.
The hybrid MRA also has an enhanced
electrical connection to help eliminate
above- and
below-cover
burning due to
vehicle vibration.
The connector is
upgraded from a
MetriPack 150 to
GT280.
The MRAs
have an improved
pump design to
increase pump
life and reduce
pump noise. The
pump is changed
from a roller vane
design to a gerotor design.
• Always install a new
strainer (never re-use)
• Replace the fuel tank
O-ring when installing a
new fuel pump
• Always follow the directions provided with the
new fuel pump
Hybrid MRA enhancements:
A. GT280 connector
B. Gerotor pump
C. Ceramic card sensor
• Inform the customer about not
using fuel additives, except for
manufacturer-recommended products, such as ACDelco Fuel System
Treatment Plus. Remember that any
additive that is put into the fuel
tank, such as to clean the fuel
injectors, must first go through the
fuel pump.
Corrosion and Contamination
The sulfur contaminants found in
some of today’s gasoline can have
corrosive effects on the fuel system
sending unit, disrupting electrical
continuity and leading to erratic or
false fuel gauge readings.
ACDelco Fuel System Treatment Plus
— 20 ounce bottle part number 10-3003
(88861013); 12 ounce bottle part number
10-3004 (88861262) — has a filmer
additive that, when used regularly, helps
protect the sending unit by cleaning
sulfur corrosion and coating the metallic
surfaces of the fuel system. It’s recommended to use ACDelco Fuel System
Treatment Plus at each oil change.
Hybrid Technology
ACDelco’s Hybrid Modular Reservoir
Assembly (MRA) features new
technology that is designed to increase
Fuel Pump Control Module
With electronic returnless fuel
systems, the Fuel Pump Control Module
(FPCM) controls the voltage supplied
to the fuel pump (located within the
fuel tank) to achieve the desired fuel
pressure requested by the Engine
Control Module (ECM). There is also a
fuel line pressure sensor, which sends a
feedback signal to the FPCM, so the
FPCM can determine whether the
desired pressure is being achieved.
Examples of vehicles first equipped with
the new FPCM include 2008 full-size
Chevy and GMC pickups.
DTCs stored in the FPCM may be
due to issues with the electrical wiring
or connectors in the FPCM circuit; or
due to performance issues within the
FPCM module, the fuel line pressure
sensor, fuel pump MRA, or communications with the ECM.
Using a scan tool to check the FPCM
for DTCs could lead to more accurate
diagnosis of a condition, faster determination of root cause, and shorter vehicle
repair times.
– Thanks to Mike Militello, Alan Lustre
and George Nagrant
ACDelco TechConnect is published bi-monthly
and online for technicians of Total Service
Support (TSS) and Key Fleet accounts to
provide timely service information, increase
knowledge and improve the performance of
the service center.
Publisher:
Mike DeSander
ACDelco
E-mail /
mike.desander@gm.com
Editor:
Mike Militello
ACDelco
E-mail /
michael.militello@gm.com
Technical Editors:
Mark Spencer
E-mail /
mspencer@gpworldwide.com
Jim Horner
E-mail /
jhorner@gpworldwide.com
Production Manager:
Marie Meredith
Desktop Publishing:
5by5 Design
E-mail /
dkelly@5by5dzign.com
Write to: *
ACDelco TechConnect
P.O. Box 500
Troy, MI 48007-0500
:
On the Web:
To read and search recent issues of
TechConnect online:
– www.acdelcotechconnect.com,
click on the TechConnect Magazine
link, or
– Log on to the ACDelco LMS, click
on the Resources link
ACDelco service tips are intended for use by
professional technicians, not a “do-it-yourselfer.”
They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have
the equipment, tools, safety instructions and knowhow to do a job properly and safely. If a condition is
described, it cannot be assumed that the information applies to all vehicles or that all vehicles will
have that condition.
All materials and programs described in this
magazine are subject to change. Submission of
materials implies the right to edit and publish.
Inclusion in the publication is not necessarily an
endorsement of the individual or the company.
TechConnect is published for ACDelco by Sandy
Corporation, Troy, MI.
©2009 ACDelco. All rights reserved.
2
Cool Technology Covered
in Latest A/C Seminar
ACDelco’s updated air conditioning system seminar, Emerging
A/C Technology and Service
(S-AC07-03.01SEM), provides an
overview of the latest issues
affecting current and future A/C
system service.
A/C systems have changed
dramatically over the past years,
becoming smaller, increasingly
efficient and more complex.
Refrigerant capacity, for example,
has dropped from nearly four
pounds of refrigerant in older R-12
systems to 16 ounces or less on
newer R-134a systems. A very
small leak can significantly reduce
performance or cause noise in a
modern A/C system.
In the seminar, technicians will
learn about:
• Various A/C systems and their
operation and service
• Scan tools, Service
Programming and CAN data
and how they involve A/C
diagnostics and repair
• Various service items such as oil
balancing, flushing, filters, line
repair, dyes and leak detection
• Various sealants and their affect
on the A/C system
• New SAE regulations for leak
detection, refrigerant purity and
R/R/R machines
• Clutchless and high voltage
hybrid compressors
• Possible future refrigerants and
their systems, such as R-152a,
R744 (CO2) and HFO-1234YF
Virtual Networks
Vehicle networks and programming have grown to control a
variety of A/C system operation,
taking information sharing of the
climate control system as well as
other vehicle systems to a higher
level of communication. In the
seminar, the use of a virtual
network in modern vehicle communication systems is covered.
A virtual network is supported by
virtual devices, which represents a
collection of signals owned by a
single physical device (control
module). A virtual network is triggered by activated switches, such
as an A/C request or a change in a
sensor. The benefit of a virtual
network is a reduction in power
consumption because control
modules are only powered when a
provided functionality is required.
Virtual network of an A/C system
New Regulations
The seminar also covers a
number of emerging topics that
are making news in the A/C
industry. This includes the following new SAE regulations:
• J2788 Standards for
Recovery/Recycle/Recharge
machines
• J2810 Standards for recovery
only machines
• J2670 A/C Additives
• J2791 Enhanced Leak Detection
• J2776 Purity Standards for
R134a
A/C refrigerants discussed in
the seminar include several new
refrigerants that are potential
replacements for R-134a. R-134a
has a Global Warming Potential
(GWP) of 1410. Worldwide efforts
to reduce greenhouse gases have
led to an agreement that any
replacement refrigerant must have
a GWP of 150 or less. Currently,
the EPA does not identify any
replacement refrigerant for R-134a
systems and has not evaluated any
alternative refrigerants.
Learn More
For more information about
ACDelco training courses on A/C
systems and other systems and
components available at training
centers and online, go to
www.acdelcotechconnect.com
and click on the Training tab.
Contact your local ACDelco
distributor to learn when the
Emerging A/C Technology and
Service seminar and other seminars will be held in your area.
– Thanks to Mike Militello
3
A/C Compressor
Service Tips
ACDelco studies have shown replacement air
conditioning compressors fail four times more
often than original compressors because of a failure to properly restore the system. ACDelco has
disassembled, reviewed, and analyzed hundreds
of air conditioning compressors returned under
warranty. The failure of these compressors can
be grouped into three major categories:
• Lubrication
• Refrigerant
• Debris
When repairing A/C conditions, performing the
necessary service to protect replaced parts is
important to avoid replacement failures and
comebacks. Prior to and after compressor failure,
debris particles from a failure flow throughout
the refrigerant system in both directions. These
particles imbed themselves in various internal
components and cannot be completely flushed
from the system.
The most cost-effective service method for
protecting the compressor and other new
components is to install a suction screen ahead
of the compressor and an in-line filter ahead of
the control valves. These protection devices have
virtually no effect on overall A/C system performance but they greatly improve the protection of
a compressor from any residual failure debris.
A quick visual inspection
may prevent needless
compressor replacement
caused by other conditions,
such as a low charge,
Diagnostic Trouble Codes
(DTC), electrical connections, or loose fasteners.
Fragment
Check for proper charge
contamination
levels and purity as well
as confirmation of clutch
engagement. Compressors with a low charge
make noise. A proper charge may silence a noisy
compressor.
Job Aids Online
For more information about A/C compressor
installation, a printable .pdf file is available
on TechConnect Magazine Online. Go to
www.acdelcotechconnect.com and click on the
TechConnect Magazine tab. The A/C compressor
job aid and several other job aids are available
under the Troubleshooting PDF Job Aids link
in the Resources section on the right side of
the page.
The job aid includes a number of tips to follow
when installing an A/C compressor. The job aid
also provides a list of related components that
should be inspected when troubleshooting the
A/C system. The operation of many of these
components will affect the performance of the
compressor. Finally, there are several tips to
verify proper installation and operation to help
ensure customer satisfaction.
Overlooked Maintenance Items: Wipers and More
More than 80 percent of the vehicles
that have been inspected at community
car care events across the country over
the past year were in need of service
or parts, reports the Car Care Council.
This reinforces the need for consumer
education about the benefits of regular
vehicle care and maintenance, especially as the number of years owners keep
their vehicles continues to increase.
Top problem areas typically found
include the need for oil changes, windshield wipers, air filters, and improperly
inflated or worn tires.
Forgotten Wipers
Wipers appear to be one of those
items that drivers forget about when
they are not in use. However, once the
rain starts to fall, the need to replace
worn wipers becomes evident rather
quickly, and good visibility has a major
impact on driver safety.
The replacement interval of wipers is
based on several factors, including
operating conditions (winter conditions
are tough on wiper blades, yet wiper
blades can deteriorate faster and need
more frequent replacement in sunsoaked desert states), frequency of use,
and the material and type of wipers.
Wiper blades should be inspected
every six months. Streaking or chattering blades as well as worn or split
rubber are signs that it’s time to replace
the wiper blades.
ACDelco wiper products feature:
steps — many of which are put off
or overlooked by drivers — be recommended to service customers. Checking
these items is especially timely after a
harsh winter’s worth of driving:
– Beam wiper blades — the latest in
wiper technology
– Change the oil and filter regularly
according to the owner’s manual
maintenance schedule.
– Performance blades that feature
pre-installed adapters that match
a vehicle’s arm type for quick
installation
– Inspect the tires for proper wear
and check the tire pressure at least
monthly, including the spare.
– Aerodynamic designs that help
prevent windlift
– Broad range of sizes and types of
blades, including low profile and
hard-to-find applications
– Materials and finishes (polymer or
carbon steel) that are designed to
resist rusting, chipping and bending
– Coatings on rubber parts that help
reduce streaking, friction and noise
– Virtually all-makes and all-models
coverage
Maintenance Recommendations
To help ensure the reliability and
safety of a vehicle, as well as to extend
vehicle life, the Car Care Council
suggests these preventive maintenance
– Have the alignment checked at
least annually. Potholes and other
road conditions can take their toll
on a vehicle’s steering and suspension.
– Check the hoses and belts — which
are critical to the proper functioning
of the electrical system, air conditioning, power steering and the
cooling system — for cracks,
brittleness or other signs of
excessive wear.
– Inspect the windshield wipers and
lights on the vehicle.
All of these components are
often neglected wear items that are
needed for safe and reliable vehicle
performance.
– Thanks to Chris Vermette
Improper Use of Conductance Testing on
New Batteries
A new battery does not develop its
full performance capabilities until it has
been through several discharge/charge
cycles. This means a new battery may
not be capable of producing its optimum
current and cold cranking amps (CCA).
If a new battery that has not gone
through a cycling period is tested using
a conductance-type battery tester,
the resulting CCA may be lower than
indicated on the battery’s rating label.
This could lead to condemning an
otherwise good battery.
Conductance is a measurement of a
battery’s current producing capability.
Conductance testers can accurately
identify batteries that have reduced
performance after being in service, but
should never be used to determine the
state of health, state of charge or CCA
rating of a new, never installed battery.
Also, conductance testing of new
batteries should never be used to
determine the warrantable condition.
To check
the condition
of a battery
prior to installation to be
sure there
is adequate
voltage to
start the vehicle, measure
open circuit
voltage (OCV)
using a digital
voltmeter
(DVOM).
An OCV of
12.24V is
Don’t use a
adequate
conductance tester to
to provide
measure the performance
the power
of a new battery.
requirements
for starting most vehicles under most
conditions. The battery should be in
service for several days before performing a conductance test.
4
Battery Testing Procedures
Follow these tips when using a
conductance tester to ensure accurate
test results. Using non-approved
adapters or improper test procedures
can lead to failing test results for
batteries that are not defective.
Be sure the battery in the tester is
good or you may get inaccurate results.
To check the conductance tester, be
sure OCV on the tester matches the
OCV measured with a known-good
DVOM (may vary slightly due to
different internal resistance).
Be sure to get good connections
between the battery terminals and the
tester clamps. Each tester clamp has
two jaws. Each jaw is wired to a different part of the tester, and it is essential
that both jaws make good contact.
If the connections to the battery
terminals in the vehicle are in doubt or
continued on page 5
Labor Times Now Available on WIP
Why use two sources to check
mechanical labor times and parts
pricing and availability? ACDelco’s
WISE Internet Parts (WIP) now offers
users the ability to do both in one
application, at no additional charge.
WIP, ACDelco’s Web-based parts
catalog application, provides fast
parts inventory access and comprehensive parts ordering. ACDelco
WIP subscribers can check inventory
and order parts online anytime from
WISE-enabled ACDelco Warehouse
Distributors. Now, labor times also
are only one click away. Using the
labor time feature will help subscribing
service centers to quickly create
parts and labor estimates. This new
feature does not apply to TurboPart
WIP users.
The addition of listing labor times
in WIP is just one of many benefits.
WIP also provides:
To display labor times, users will
identify and search for parts as
they have in WIP previously. Build
the vehicle for which the parts are
needed by selecting the year, make,
model and engine, or enter the VIN.
Next, select the parts group and
subgroup.
– The ability to place parts orders
anytime 24/7 with local warehouse
distributors
Once users have identified the vehicle
and parts they are interested in, click on
the Display Parts & Labor button or the
Display Labor Only button. Labor times
for the selected parts will be displayed
below the parts information.
The labor multiplier value used
to calculate the labor times also can
be changed. Click the Edit Labor
Multiplier button to increase or
decrease the multiplier.
– A direct link to local warehouse
distributors using your PC and
Internet connection, no additional
hardware or software is required
– Access to the inventory of local
warehouse distributors to check
parts pricing and availability
To learn more about WIP, visit
www.acdelcotechconnect.com, call
1-800-825-5886, prompt #3, or contact
your local ACDelco representative.
– Thanks to Bob Stewart
Labor times for parts searched in WIP.
Parts and labor or labor only can be displayed in WIP.
the tester displays REPLACE BATTERY or BAD CELL REPLACE, disconnect the battery being tested from the
vehicle. Retest the battery with both of the vehicle’s battery
cables disconnected from the battery.
Expanded Wiring
Sockets and Pigtails
Search Tool
When using an adapter, be sure the adapter makes good
contact with the lead terminal surface on the battery.
The wiring sockets and pigtails search tool on
www.acdelcotechconnect.com has been expanded.
Never use steel bolts, nuts, washers, etc., when testing
a side terminal battery. Only use the adaptors included with
the conductance tester. The coating on other adapters may
affect the tester’s accuracy.
This on-line reference source offers a menudriven search feature that can narrow the search according to brand, number of cavities and gender. With
photos of each pigtail and wiring socket, you also can
visually match the part you are replacing with the new
part number. All of which makes it easier to identify
wiring sockets and pigtails for GM and non-GM vehicles.
Battery Warranty
ACDelco batteries are covered by a comprehensive
warranty program. Any independent service center can accept
an ACDelco battery that is under warranty and not functioning
properly from a customer for return, even if the battery was
purchased from another retailer or service center. ACDelco
will warrant the battery, and in the process, the service
center may earn some additional service business and
customer loyalty.
– Thanks to Mike DeSander and Brad Busboom
To access the wiring sockets and pigtails search tool,
go to www.acdelcotechconnect.com and click on the
Automotive Systems tab and the Product Information
link.
– Thanks to Bob Stewart
5
GM New Vehicle
Supplier Discount
plus Other Incentives
Add Up
The TSS Q&A provides answers
to common questions received
by the ACDelco Customer
Support Center.
Q: How does the web-based ACDelco TSS
Customer Satisfaction Index (CSI) Program
track customer satisfaction?
There are several money-saving regional consumer
incentives available right now on most 2009 GM cars and
trucks. TSS service center owners and employees who add
those to the thousands in savings available through the GM
New Vehicle Supplier Discount will find that the amount of
money off really adds up.
A: The new TSS CSI Program provides for
immediate feedback from service customers.
The system features hang tags with the service
center’s ACDelco TSS account number that are
given to customers after service has been
performed. Customers can go online to
http://survey.acdelcocrs.com, enter the TSS
account number on the tag, and provide their
comments about their service experience.
The GM supplier discount is available on most new 2009
GM vehicles at participating GM dealerships. Vehicles may
be taken from dealer stock or ordered. (Eligibility may change
at any time without notice and some models may have
limited availability). All that’s needed to get your supplier
discount savings is a GM New Vehicle Supplier Discount
authorization number.
Q: How is the customer information delivered to
service centers?
To get your authorization number, follow these steps:
A: The data is compiled
for the service center.
All the service center
has to do is hang the
tag on a customer’s
rearview mirror when
service is finished.
Once a customer
answers the online
survey, a link to where
the survey results can
be accessed is sent via
e-mail to the service
center. The service
Customers fill out the
CSI survey online.
satisfaction comments
and CSI scores are available immediately, providing instant feedback.
– Go to www.acdelcotechconnect.com
– Click on the Total Service Support tab, and then the
ACDelco TSS GM Vehicle Supplier Discount button on
the right side of the page. (You will have to log in by
entering your 6-digit TSS code [it begins with a 6] and
your zip code.)
– On the GM Vehicle Supplier Discount page, scroll down
to the bottom of the page and click on the link
www.gmsupplierdiscount.com to access the GM supplier
discount website. Always access the GM supplier discount website through www.acdelcotechconnect.com.
This loads the website with the correct company code
for TSS service centers.
– If you have used this website before, input your user
name and password that you have used in the past. If you
do not have a user name and password, click on New to
Supplier Discount to register on the site.
For more information about the TSS CSI Program,
go to www.acdelcotechconnect.com, select the
Total Service Support tab, and then click on the
Marketplace link. After logging in with your sixdigit TSS account number and zip code, scroll
down and select the Customer Satisfaction Index
Program. You also can call 1-800-825-5886,
prompt 4, for more program details.
– Click “yes” when you are asked, “Are you a TSS/ACDelco
account?” This question will only appear if you have
logged in using a previous user name and password.
– If you are asked if you would like to use this new account
number because it has changed, always respond “yes.”
This is part of a recent change to improve the process.
If you have any questions about the TSS program
or any current ACDelco activities, contact the
Customer Support Center at 1-800-825-5886,
prompt 0.
– Begin by selecting GM Supplier Discount on the top left
side of the page. Next, click on Obtain Authorization to
generate your GM Discount Certificate. You will be asked
for your birth date, zip code, and other vehicle purchase
information. Click on Step 2 and Step 3 after verifying the
information.
– You can print out the certificate number, write it down, or
email it to a recipient. It’s that easy!
Correction
For additional information about the GM supplier discount
or if you have questions about the authorization number
process, call 1-800-960-3375. When calling, please state
that your company name is TSS/ACDelco, not your individual
service center name.
– Thanks to Staci Shelton
In the last issue of TechConnect, an article about
counterfeit tools stated that authentic CANdi modules
have aluminum terminals. It should have stated that
authentic CANdi module terminals may be either nickel
or gold.
6
The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual
service repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technical
expert with the latest OEM information.
Disconnect the #6 circuit lead at the
starter “S” terminal. With the ignition
Off or in Run, use an Ohm meter to
check for any electrical path between
the ring terminal on the #6 circuit lead
and ground.
Intermittent Vehicle No
Crank/Dead Battery
2004 Buick Rainier; 2000-2004
Cadillac Escalade, 2002-2004 Cadillac
Escalade EXT, 2003-2004 Cadillac
Escalade ESV; 1998-2004 Chevrolet
Blazer and S-10 Pickup, 1999-2004
Chevrolet Silverado, 2000-2004
Chevrolet Suburban and Tahoe,
2002-2004 Chevrolet Avalanche,
2002-2004 Chevrolet TrailBlazer and
TrailBlazer EXT, 2003-2004 Chevrolet
Express; 1998-2004 GMC Jimmy and
Sonoma, 1999-2004 GMC Sierra,
2000-2004 GMC Yukon and Yukon XL,
2002-2004 GMC Envoy and Envoy XL,
2003-2004 GMC Savana, 2004 GMC
Envoy XUV; 1998-2004 Oldsmobile
Bravada; 2003-2004 HUMMER H2
When diagnosing an intermittent
vehicle no crank or dead battery
condition, remove and reinstall the
ignition switch following the appropriate
procedure in the Service Information.
The ignition switch may have been
misindexed in the steering column
during a previous replacement.
If the ignition switch is misindexed
in one direction, the ignition switch
circuits will not be completely open
when the ignition switch is in the Off
position with the key removed. This may
result in the lights remaining on and will
drain the battery.
If the ignition switch is misindexed
in the opposite direction, the ignition
circuits will open correctly, but the
ignition switch may not close the crank
circuit properly when the ignition key is
turned to the crank position. This will
result in a no crank condition.
Refer to GM bulletin 04-06-03-002 for
more information.
Low Voltage Display
1998-2008 GM Passenger Cars
and Light Duty Trucks, including Saturn;
2003-2008 HUMMER H2, H3;
2005-2008 Saab 9-7X
These vehicles may have a low
voltage display, lights that dim at stop
lights, slow cranking, no start, low
generator output at idle or dim lights at
idle when electrical loads are heavy at
idle or under slow driving or infrequent
usage conditions. These characteristics
If found, eliminate the grounding
condition. Reroute any wires as
necessary.
Alternator Bolt Tightening
2001-2004 Honda Civic
Low voltage display
may be more noticeable with customeradded electrical accessories or with a
discharged battery.
These are normal operating characteristics of a vehicle electrical system
unless a proven fault has been
diagnosed.
Non-usage of the vehicle for
extended periods of time and extended
periods of engine idling with high
electrical loads are two factors that
may affect generator and battery performance. For complete diagnosis of the
battery and/or generator, refer to the
appropriate Service Information.
Refer to GM bulletin 05-06-03-002B
for more information.
Starter Motor Continues to
Run or Crank
1995 Buick Riveria; 1995 Cadillac
Eldorado, Eldorado Touring Coupe,
Seville; 1995 Chevrolet Camaro; 1995
Oldsmobile Aurora; 1995 Pontiac
Firebird – with 3800, 4.0L, 4.6L, 5.7L
engines (RPOs L47, L36, LT1, LD8, L67,
L37); 1994-95 Chevrolet and GMC Truck
C/K, G, P models – with 5.7L, 7.4L
engines (RPOs L05, L19)
The starter motor may continue to
run or crank after the vehicle is started
or turned off. The starter motor solenoid
will not disengage because of a ground
to the #6 circuit. With the #6 circuit
ground to a resistive ground, current is
fed back through the windings to the
ground, holding in the plunger and
causing the starter to continue to run.
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Conditions such as an engine
crank/no start, MIL on, immobilizer
blinking, or no communication with the
ECM/PCM may be caused by loose
alternator bolts. If these bolts are loose
for any reason, the alternator can
overcharge and damage the ECM/PCM.
Beginning in 2001, the Civic has a
different style alternator bracket that
makes the bolt tightening sequence and
bolt torque critical. Improper tightening
will cause noise.
Refer to the appropriate Service
Information for the proper bolt tightening sequence and bolt torque specifications. A belt tension gauge special tool
also is required.
After tightening the alternator bolts,
restart the engine. If it won’t start,
check the ECM/PCM connector for
battery voltage and ground. If there is
battery voltage and ground at the
connector, replace the ECM/PCM.
Diagnostic Assistance
For free technical diagnostic
assistance and product information
regarding specific ACDelco products,
contact these toll-free information
hotlines staffed by ASE-certified
technicians:
Brakes – 1-888-701-6169 (prompt #1)
Chassis – 1-888-701-6169 (prompt #2)
Clutches – 1-888-725-8625
Lift Supports – 1-800-790-5438
Shocks – 1-877-466-7752
Starters and Alternators –
1-800-228-9672
Steering – 1-866-833-5567
Wiper Blades – 1-800-810-7096
Current Instructor-Led
Training
Course Number
Course Name
S-AC07-02.01ILT
Automotive Air Conditioning: Advanced Refrigerant System Diagnostics
S-AC07-03.01ILT
HVAC Control System Operation and Diagnostics
S-AC07-06.01ILT
Toyota HVAC
S-AC07-07.01ILT
Chrysler HVAC
S-BK05-01.01ILT
Braking Systems
S-EL06-04.01ILT
Body Control Systems Diagnostics
S-EL06-10.01ILT
Battery, Charging, & Starting
S-EL06-11.01ILT
Automotive Electrical Circuit Diagnosis and Repair
• To enroll in an Instructor-Led
Training (ILT) course, click on
the Enrollment link or the
Instructor-Led Courses link.
S-EL06-12.01ILT
Hybrid Technology and Service
S-EP08-02.01ILT
Engine Performance: Computer Controls and Ignition System Diagnostics
• To launch a Web-Based Training
(WBT) course, click on the
Web-Based Courses link to
view the catalog and select a
specific course.
S-EP08-03.01ILT
Engine Performance: Air Induction and Fuel System Diagnostics
S-EP08-04.01ILT
Engine Performance: Fault Monitoring and Emission System Diagnostics
S-EP08-05.01ILT
Engine Performance: Advanced Drivability Diagnostics
• To launch a TechAssist (TAS)
course, click on the TechAssists
link to view the catalog and
select a specific course.
S-EP08-20.01ILT
Toyota Engine Performance
S-EP08-21.01ILT
Chrysler Engine Performance
• To launch a Simulation (SIM),
click on the Simulations link to
view the catalog and select a
diagnostic challenge simulation.
S-EP08-81.01ILT
Duramax 6600: Diesel Engine Performance
S-SS04-01.01ILT
Vibration Correction Diagnostics
S-ST10-01.01ILT
Supplemental Restraint Systems
ACDelco’s Instructor-Led Training
(ILT) courses provide hands-on
instruction on the latest automotive
systems. The following ILT
courses are currently being held
at training center locations around
the country.
How to Take
ACDelco Training
To log on to the ACDelco Learning
Management System go to
www.acdelcotechconnect.com
and click on the Training tab.
Readers Show Off Their Rides
1. Go to the TechConnect Magazine Online website
by clicking on the TechConnect Magazine tab on
www.acdelcotechconnect.com
A few American classics are some of the rides TechConnect
readers have submitted for the Readers’ Rides gallery on
TechConnect Magazine Online. To get the story behind the
cars of fellow TSS shop owners and technicians and view a
gallery of the cars, go to www.acdelcotechconnect.com and
click on the TechConnect Magazine tab.
2. Click on the Contact Us link
3. Send an email with photos attached to technical
editor Mark Spencer
– Thanks to Mike DeSander
To submit photos of your car or truck (include your name, TSS
center, location and a few technical details about your vehicle):
1976 Chevy Chevelle Laguna S-3,
Scott Hamilton,
Hamilton’s Car Care, Arlington, Texas
TS-PU-0008-09
1971 Dodge Dart Swinger,
Bill Levine,
Hamden Public Works, Hamden, Conn.
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1970 Chevy Chevelle SS,
Ricky Stephenson,
Car Concepts, Inc., Hurst, Texas