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General Performance Chip/ECM/PCM
Trouble Shooting Chart
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OBD2 trouble code chart and
diagnostic connector location
CLICK HERE |
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For Complete OBD2 Trouble Code
Listings,
CLICK HERE
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For OBD1-2 "Set Timing" Instructions,
CLICK HERE
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My starter
doesn't engage ... |
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Read the supplied information
carefully after installing the PCM for a quick relearn
procedure--pay attention to the passkey information !!
Did you disconnect the battery when
installing your chip ?? Recheck your battery connections. Aside
from the Corvette and some Cadillac models, there are no other
earlier GM calibrations prior to 2001 that use the computer to
interrupt the start circuit.
A Ford performance module is
impossible to install upside down, and some Ford computers
(1998-2000) need to have the J3 segments connections soldered for
a complete connection to the ECA processor. Without this repair,
the Ford performance chip will not work and the "Theft" light will
rapidly flash.
If you supplied us with a
calibration number other than what your car originally came with
or engine was designed for, your vehicle may not start. If you
need the VATS or Passkey disabled, you must tell us this at order
time.
For GM FLASH PCM/VCM
replacement, the PASSKEY RELEARN PROCEDURE must be done:
The typical 1998+ Car and Truck
Passkey/Antitheft relearn procedure is this:
1. Disable your headlamps (Park
Brake Apply--do not remove headlamp relay).
Attempt to start
the vehicle (this means you rotate your ignition key fully to the
start position). Vehicle may or may not 'fire' and quit. Some
vehicles will not allow starter motor engagement, and this is
normal. DO NOT TURN OFF KEY YET !!
2.
Leave
the key in the "on" position, until the 'security' light goes out
or quits alternately flashing between "Security" and "Battery".
This relearn period always takes 10 minutes. How long does this
take ? 10 minutes. How long do you have to wait ? 10 minutes.
3. After the security light is no
longer displayed on the instrument panel cluster, shut the key off ! Wait 5-10 seconds and repeat
the above procedure (steps 1 through 3) two more
times for a total of 3 start-relearn-attempts, remembering to shut
the key off between each 10 minute relearn procedure. This will
take 30 minutes--no less. If the 4th start attempt fails to start
the vehicle you did one relearn step (or all of them incorrectly).
If you left your headlamps on until the battery went dead and
voltage dropped below 10.5 volts, no amount of relearn attempts
will be learned !!
Don't read too much
into this. Most people cannot seem to grasp the simplicity of this
relearn procedure.
New for
LS2 (2005+)...Here is the GM procedure to relearn the VTD code:
1. Press the START button.
2. Observe the Security telltale. After approximately 10
minutes the telltale will turn off.
3. Turn OFF the ignition, and wait 5 seconds.
4. Repeat steps 1-3 two more times for a total of 3 cycles or
30 minutes.
Important !!!
The vehicle learns the passwords on the ignition switch
transition from OFF to CRANK. You must turn the ignition OFF
before attempting to start the vehicle.
5. Start the vehicle. The ECM has now learned the RCDLR
password.
Make sure there are
no bent pins in your ECM connector or pushed out harness pins in
the wiring harness. IF a pin has been broken on your ECM, we can
repair or replace your ECM/PCM for a small fee.
If this is a new
engine installation, carefully check for missing "ground" wiring
or an unplugged harness connection.
A performance chip
(replacement chip--not replacement computer)
will always allow the starter to engage the engine flywheel (with exception
of some earlier Corvette calibrations--or 2001+ VCM's), so don't
blame a 'chip' on a starter or ignition switch failure.
A freshly painted
engine block can inhibit the ground path to the starter...clean
those grounds !!
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My starter
engages, cranking RPM is normal -- but engine will not fire... |
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Read the supplied
information carefully after installing the PCM for a quick relearn
procedure--pay attention to the passkey information !!
Did you disconnect
the battery when installing your chip ? Even a static discharge
can ruin your new calibration. Treat this calibration chip with
extreme care. If you also fail to disconnect the battery when
swapping chips, the RAM memory retains the values from the
previous chip. It will take a long time before new closed loop
values are learned. Do not swap chips back and forth without
disconnecting the ECM from power, without disconnecting your
battery, or without pulling the ECM fuses first.
The second thing to
check is if you installed the chip correctly. A GM Prom chip has a
notch in one end--it must align to the notch in the carrier as in
the supplied instructions. Many people install the chip
backwards--this will often damage the chip. A memcal is impossible
to install backwards, but with enough force it "could" happen. If
the chip is correctly installed and the car still doesn't
start--see if the check engine light is rapidly flashing or
steadily on--you may have bent a chip "leg" at installation. If
you do damage a chip--just send it back to us--we'll immediately
send you a new one.
If you supplied us
with a calibration number other than what your car originally came
with or engine was designed for, your vehicle may not start. If
you need the VATS or Passkey disabled, you must tell us when you
place your order.
For GM FLASH PCM/VCM
replacement, read above PASSKEY RELEARN PROCEDURE :
Make sure there are
no bent pins in your ECM connector or pushed out harness pins in
the wiring harness. IF a pin has been broken on your ECM, we can
repair or replace your ECM/PCM for a small fee.
If this is a new
engine installation, carefully check for missing "ground" wiring
or an unplugged harness connection, vacuum leak or bad MAF.
A performance chip
will always allow the starter to crank the engine (with exception
of some Corvette calibrations--or 2002+ VCM's), so don't blame a
chip on a starter or ignition switch failure.
New computers need
a learn/relearn period. A common trouble code is P1336 or P0315
(Cam/crank sensor position relearn). Sometimes a no-start can
occur because the idle has not been learned yet. Read the supplied
information carefully after installing the PCM for a quick relearn
procedure--pay attention to the passkey information !! We've
recently found that some PCM's will not talk to the databuss for a
while. Disconnect the battery and let sit for 15 minutes (this is
after you've learned the Passkey). Reconnect battery and then
reattempt to start.
If no "quick learn"
procedure was provided for you, it doesn't need one--simply start
the vehicle with 10-15% throttle. Allow to idle. When the idle is
stable, put the vehicle in gear with the brake applied. Allow for
the idle to stabilize for 20-30 seconds. Return to park. Shut off
and re-start to see if the idle is now stable. Repeat if engine is
not at operating temperature, and repeat with the airconditioning
or high electrical load on (headlamps).
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My starter
engages, but engine starts and stalls... |
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Read the supplied
information carefully after installing the PCM for a quick relearn
procedure--pay attention to the passkey information !!
For GM FLASH PCM/VCM
replacement, read above PASSKEY RELEARN PROCEDURE :
If no "quick learn"
procedure was provided for you, it doesn't need one--simply start
the vehicle with 10-15% throttle. Allow to idle. When the idle is
stable, put the vehicle in gear with the brake applied. Allow for
the idle to stabilize for 20-30 seconds. Return to park. Shut off
and re-start to see if the idle is now stable. Repeat if engine is
not at operating temperature, and repeat with the airconditioning
or high electrical load on (headlamps).
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My car starts and
runs, but idles poorly and the check engine light is on... |
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Did you remember to
install the knock module in your 1994-2000 PCM as instructed ? If
so...read further.
Find out what
your "trouble code" is and phone or email us immediately. We'll
guide you through the diagnostic process or fax you repair
information. If you're familiar with OBD1 diagnostics and know how
to access trouble codes, good ! If not--give us a call and we'll
help you out. Refer to the enclosed sheet that came with your
performance chip on how to access the trouble code information.
OBD2 (1995 and up import and domestic vehicles) require a scan
tool for diagnostic analysis. Check
www.autoenginuity.com
for some good software/hardware scan tool
packages which we endorse. This scanner actually times each
scanned event, making it a much more reliable option than some of
the other 'scanners' out there.
Some vehicles
require a P1336 or P0315 relearn procedure which is performed with
a scan tool with bi-directional controls. Most off the shelf scan
tools will not do this procedure. Scan tools from OTC, SnapOn or
other aftermarket (non-OEM) may or may not perform the procedure
properly, either. Do not waste your money on a $200 store bought
code reader--this will not help you. A common trouble code is
P1336 or P0315 (Cam/crank sensor position error). Sometimes a
no-start can occur because the idle has not been learned yet. IF
we sent you the computer FROM your vehicle (which you sent us),
there should be no CASE relearn procedure or passkey relearn
required.
Newly installed
computers also need a learn/relearn
procedure.
The "idle air
control" valve may not have as yet learned it's new
position...perform the IAC relearn procedure for GM.
Typical relearn
is this:
1. Start
vehicle and allow to idle--allow to reach normal operating
temperature. Allow to idle in varying gear positions
(drive/neutral) for up to 3-5 minutes in each position. Then redo
with the A/C on and headlights on ! Some times you may have to
coax the idle a bit to maintain an idle--so help it along with the
gas pedal !
f no "quick learn"
procedure was provided for you, it doesn't need one--simply start
the vehicle with 10-15% throttle. Allow to idle. When the idle is
stable, put the vehicle in gear with the brake applied. Allow for
the idle to stabilize for 1-2 minutes. Return to park. Shut off
and re-start to see if the idle is now stable. Repeat if engine is
not at operating temperature, and repeat with the airconditioning
or high electrical load on (headlamps).
Often,
"performance" plug wires cause RFI interference which can corrupt
the signals that your computer receives. Many a problem have been
solved by simply checking and solving some ignition errors. Check
spark plugs for porcelain cracks, broken insulators or incorrect
plug gaps. A cracked reluctor in a distributor can actually double
the 'tach' pulse, causing a very interesting fuel injection pulse
width--again, don't overlook your distributor if so equipped.
A leaking EGR valve
is an often discovered problem. This causes lower than normal
manifold vacuum, affecting the MAP sensor to ECM readings.
A dirty MAF sensor
also causes drivability and idle problems.
Check for an
unplugged sensor. Check sensor grounds and sensor supplied
voltages. Don't overlook incorrectly installed vacuum lines.
Do not overlook bad
grounds, painted mountings or anything that would interfere with
good body to chassis connections. Painted bellhousing to
transmission surfaces can often lead to early transmission failure
or poor electronic communications between the PCM and sensors or
solenoids in a transaxle or transmission. Make sure your battery
has connections to both engine block and vehicle body on the
negative side--and good positive connections where required. A bad
tail-light bulb (part of the TCC circuit) can cause early
transmission failure in most Ford products--so pay attention to
every detail !
Some calibrations
or custom hot rods do not use all sensors--if you failed to tell
us this, your check engine light will be illuminated.
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My car starts and
runs, but idles rich or lean...no check engine light. |
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#1 "rich" problem
is a leaking EGR valve. Always check to make sure that this valve
doesn't have a leaking pintle and seat--and make sure the EGR
solenoid isn't energized (if exists) or that the EGR valve vacuum
port isn't being supplied with manifold vacuum. Generic EGR valves
are a very poor purchase choice.
#2 "rich" problem
is a leaking MAP sensor hose or faulty MAP sensor. Again--simple
tests will reveal the problem.
#3 "lean" problem
is leaking TBI base gaskets (accompanied by a fast idle and low
IAC "counts"). Replace the base gasket where required.
Contaminated MAF sensors which improperly measure engine airflow
will also incorrectly fuel the engine. This can lead to detonation
or very lean operating conditions.
#4 "lean or rich"
probem is an O2 sensor that has biased lean or rich. Test to see
that the O2 sensor can produce at least 150mV to 900mV. Any leaks
ahead of an O2 sensor will slew the computer calibration rich,
since the computer will think there's a "lean" problem. Faulty
cannister purge solenoids, vacuum leaks, restricted fuel
injectors, leaking fuel injectors, leaking fuel pressure
regulators, improper PCV valve, leaking MAF boot...etc. -- ALL can
cause fuel calibration problems. Please verify before calling. New
injectors are often faulty--especially 'performance injectors'.
If your TPS voltage
is too high, the ECM automatically is 'thinking' that the throttle
plate angle is higher than normal--so additional fuel is added.
Check a service manual for the proper specification (typically
0.42-0.68volts throttle plate closed).
Check base ignition
timing. It must be at the factory setting.
If you had problems
starting your car or truck, check the engine oil--does it smell
like fuel ? Check fuel pressure ! Low fuel pressure is sometimes
worse than high fuel pressure. If an injector dribbles fuel --
poor atomization is the result. If you're working with a throttle
body system, look at the injector spray pattern when running. Use
a timing light and note if the pattern changes from a 'mist' to a
solid wave at any time. If the pattern also accompanies an engine
"misfire"--check the distributor closely. The injector is fired by
the ECM via signal from the distributor.
If the calibration
doesn't run good "closed loop" let us know what the fuel trim
numbers indicate (from a scan tool). Do not phone until engine has
at least cycled the cooling fans once or the thermostat has
opened--or you've driven at least 30 miles. An ECM or PCM must
"learn" new fuel strategies--allow 'learn in' time. Speed density
systems are the most difficult to "dial" in, so if all known
problems do not seem to be apparent, we may need to recalibrate
the fuel curve. Try to include all the camshaft specifications
when you fill the order form. Do not build low compression engines
with wild camshafts--you won't like the result.
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My car starts and
runs, idles great, but is rich or lean at cruise... |
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First off--don't
overlook the basics. Plugged fuel filter, air filter, spark plug
condition/wrong reach or vacuum leaks.
1. Check the O2
sensor, restricted fuel injectors, low exhaust back pressure (non
factory exhaust system) or high exhaust back pressure--(too much
EGR)
2. Check the
ignition system for misfire, weak ignition or pickup coil, bad DIS
coil pack or leaking secondary wires (plug wires). Spray the plug
wires with a soapy water solution and listen for an engine idle
misfire--you can often visually see the ignition leakage.
3.Test ignition
coil output. An engine should be able to run (idle) with a
1/2-3/4" open gap at the ignition coil tower with a spark tester.
This is a coil "stress test".
4. Check for vacuum
leaks, fuel enriched engine oil, water in fuel, excess methanol in
fuel or high "ethanol" blend or oxygenated fuel. Do not run high
octane fuels unless instructed to do so. All factory calibrations
are designed for 85-93 octane ratings unless engine modifications
justify high octane. Volatility rates for high octane fuels can
lead to poor cold starts, vapor locking problems and poor
driveability in very hot climates. Lower octane in low altitude
can lead to detonation problems with high performance
calibrations. High octane at high altitudes can also cause
driveability problems unassociated with tuning--but can be
corrected with tuning. Higher than normal octane fuel can actually
cause code 43 (ESC) tests to fail.
Exhaust manifold to
cylinder head, or header collector leaks cause an oxygen sensor
(in closed loop) to read 'lean' -- which in turn causes the
computer to add more fuel.
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My car starts and
runs, fuel is correct at cruise, but has no power or runs lean at
WOT or rich at WOT... |
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#1 Check fuel
pressure and volume. 90% of high performance concerns are fuel
pump or filter related. A dirty "in tank" filter sock will
restrict even the best fuel pump.
#2 Restricted
injectors. (Lean) This problem may or may not show up at highway
cruise, but is very noticeable at wide open throttle. Remember the
brake specific fuel consumption rules when picking injectors for
your application. Cheap injectors are not worth the money. Buy
quality injectors, or have them flow tested.
#3 Check throttle
plate linkage for binding or incorrect throttle opening. Check TPS
voltage (should be above 4.2 volts at WOT). Check for a faulty ESC
(electronic spark control) system (no spark advance will result).
#4 Check for "false
knock". Any noise generated (whether real or RFI) to the knock
sensor or KS circuit will automatically retard ignition timing. We
once had a 454 SS truck that could hardly pull itself when towing
anything--problem was a loose hitch ball, which sent the same
knock frequency down the frame rails--and was picked up by the
knock sensor.
#5 Check for an
improper spark plug gap or spark plug reach. Wrong plug reach can
change the air fuel ratio, slow the flame front in the combustion
chamber and cause increased emissions and very low power--and low
fuel economy.
#6 Dirty MAF
sensor. If any dirt is on the sensing elements of a MAF sensor,
the fuel rate is incorrectly calculated. This can harm overall
driveability--and definitely hurt performance, as well as cause
transmission problems and detonation.
#7 Wrong MAF sensor
or failed MAF sensor. The sensor can correctly show idle flow
voltages, but cannot correctly show higher operating loads to the
computer. Very poor driveability will results, and very high
losses in power--and can result in eventual engine damage.
Mounting the MAF sensor in a non-OE position (nearer to throttle
body) can be affected by reversion pulses from the intake
manifold--and result in incorrect metered air values to the
computer.
#8 Wrong in tank
pump and regulator. For 2005, some suppliers are sending a
complete pump and regulator for supercharged applications which
are incorrect. If the pump and regulator from a VIN "Z" truck is
used, the resulting fuel pressure is 48-54 (335-375Kpa) PSI.
Factory fuel pressure for 2005 trucks (other than a VIN Z truck)
is 55-62 PSI. Because of this unknown factor, we suggest getting
the number right from the fuel pump before installing, along with
the fuel pressure regulator number--BEFORE installing it in the
tank.
#9 New problem with
some centrifugal superchargers is a unique phenomenon where at
part throttle, the buildup in pressure barks back through the
impeller--and is picked up by the MAF sensor. This causes an
instant frequency change in the MAF sensor signal to the PCM--and
results in a very rich frequency problem each time this occurs.
Wide open throttle is fine, part throttle is very poor and jerky
because of this. The only cure we've seen so far is a larger
pulley to drop the supercharger boost pressure, or relocating the
MAF sensor to the pressure side of the supercharger, just ahead of
the throttle body where it is not affected by these overlap air
burps.
OBD2 trouble code chart and
diagnostic connector location
CLICK HERE
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