buying a 3rd gen *what to know*
04-27-06, 02:40 PM
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Veilsidei
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buying a 3rd gen *what to know*
I want to buy a 3rd Gen RX-7. What should I know?
Recalls
There have been three recall notices put out on the 3rd Generation RX-7s,
two pertaining to engine fires, and one concerning brake booster failure.
You will want to make sure that the car in question has had these recalls
done. If they have not been performed, you will want to take the car to a
Mazda dealership where they will be performed free of charge. If you don't
know whether the recalls have been applied to a car, you can call the Mazda
Customer Service line at (800) 222-5500 with the vehicle's VIN, and they
can tell you.
Coolant recall
The coolant recall involved the replacement of some cooling system parts
with stronger/more heat resistant materials and lowering the pressure of
the cooling system from 1.3 bar to .9 bar. The parts replaced were the
water pump seal, the water level sensor, the upper radiator hose, the
filler cap, the filler cap body, the thermostat gasket, the water hose
leading to the throttle body, and the water hose leading to the coolant
separator tank.
Fuel line recall
The fuel line recall involved replacing the fuel lines under the intake
manifold with lines made from a more heat resistant material, and adding
a fan control unit that runs the cooling fans if the coolant gets too
hot, even if the car is turned off.
Brake recall
The brake recall involves the replacement of a vacuum check valve and
hose leading to the brake booster. The original unit may stick when
oily and cold, preventing power assist under braking.
Common questions
What is the "exhaust system overheat" light for?
The "exhaust system overheat" light is connected to a temperature sensor
inside the car, under the carpeting, by the passenger seat. The
location of this sensor is just above the main catalytic converter, and
its purpose is to warn of excessive heat being generated by the converter.
When the temperature of the passenger floor reaches about 220 degrees F,
the ECU activates the relief air bypass and bleeds off air that would
otherwise go to the catalytic converter. This has the effect of cooling
the catalytic converter.
When I start my car, the RPMs go to 3000. Why?
All 1993+ RX-7s have what is called an "Accelerated Warmup System" that
revs the car up to ~3000 RPM when it is cold-started. Its purpose is to
heat up the 02 sensor and first catalytic converter to operating
temperature as soon as possible. If you don't like the thought of your
motor revving that high when cold, you can start the car in 1st gear
(with the clutch in), and the AWS will only take the RPMs to ~1500 or so.
It is also possible to bypass the AWS solenoid (see the performance section
of this FAQ).
What does the "mileage switch" do?
The "mileage switch" is in effect for the first 20k miles on a new RX-7.
It has the same effect as the "power steering switch". It adds some RPM
to the base idle to help keep the engine from dying.
What type of gas should I use?
The RX-7 requires "super" or "premium" unleaded gasoline. Use only
gas with a 92 or higher octane rating. Using leaded gas will coat
both your catalytic converters and your oxygen sensor, rendering them
useless.
What are some of the common problems with 3rd Gen RX-7s?
Common problems with easy fixes
Oil pressure gauge reads 0 psi
Sometimes the connection between the oil pressure sending unit and the
wire to the oil pressure gauge gets loose or dirty. The way to fix this
is to clean the metal tab on the sending unit with some 0000 steel wool,
and then re-install the gauge wire using some electrolytic silicone gel
(like some sets of spark plug wires come with) to seal out grime.
No boost above 4500 RPM
This is usually caused by a vacuum line coming off of the "Charge Control
Solenoid". The lines sometimes pop off while under boost. The solenoid
in question is located under the upper intake plenum. Look in your
shop manual on page F-10, the solenoid is item F. If a vacuum line has
come off here, trim off the end of the line where it has become loose,
and re-attach it to the solenoid. It is helpful to use wire-ties or
a dab of sealant to keep them from coming off again in the future.
Motorcycle shops also sell small, wire clamps that work well.
Hood squeaks / rattles
Squeaks: Lightly lube up the tops of the rubber hood stops and the latch.
Rattles: Tighten the latch mechanism so it holds the hood to the rubber
stops with light pressure. Latch rattles can also be temporarily fixed
by wrapping a small amount of tape around the latch where it mates with
the striker plate.
Hand brake light comes on while driving
The switch that controls the parking brake indicator light is located
under the leather brake handle boot. Sometimes during acceleration the
hand brake lever moves enough to activate the light. This problem can be
fixed by building up the area of the handbrake that contacts the switch
with a product like JB Weld.
"Low Coolant" alarm goes off
The "Low Coolant" alarm goes off when the low coolant sensor is not wet.
This sensor is located on the back side of the aluminum coolant fill
housing. Simply top off your coolant level to quiet the alarm (even though
it may already look full).
Radio flashing "Err" code
This means the factory radio's anti-theft feature has been triggered. It
can be reset by entering an unlocking code. The unlocking procedure is
at http://k-rad.com. Your dealership can also unlock your radio, but
they will usually charge a fee.
Other common problems
Hesitation at 3000 RPM when cold
No known cure.
I think it is caused by the double throttle control. Its purpose is to
prevent the engine from getting an overly lean fuel/air mix when you
first start to accelerate. Now the way this system works is that when
the engine is cold, (coolant below 175 degrees or so) the ECU opens the
double throttle control solenoid, which supplies vacuum to the double
throttle control actuator. This vacuum overcomes the spring tension
that normally holds the double throttle butterfly open, and it closes.
Now, think about what happens when you accelerate.... the engine pulls
less vacuum, and starts to go towards positive manifold pressure as you
build boost. With the vacuum going away, the plate returns to its
open (normal when engine warm) position. This helps explain why the car
doesn't hesitate when accelerating hard, and does when accelerating slowly.
The decision by the ECU to operate the double throttle control system is
affected by coolant temperature, and the current "map" that the ECU is
using. The Double Throttle control only happens during starting, cold
engine warm-up, and COLD engine with LIGHT LOAD operation. This map is
also affected by the 20k mile switch, which is why many people say that
the car never hesitated at 3000 RPM when it was new. The 20k mile switch
does the same thing that the EL switch does.... it adds base RPM to the
motor... which affects the ECU's decision as to what "map" it is currently
operating in.
This is just my personal theory, and may be wrong.
Paint problems
Some RX-7 owners have experienced problems with accelerated paint chipping
and fading. Mazda has set aside some money to deal with this problem on
a case-by-case basis. If your car has this problem, call the Mazda customer
service line (800 222-5500) and ask to schedule a meeting with your local
District Service Manager to have your paint inspected.
Battery death & leakage
Many people on the RX-7 mailing list have had their batteries die
prematurely. The main cause seems to be excessive heat. Batteries
don't do well with heat, and it gets quite hot under the hood of an
RX-7. Hot batteries also tend to leak acid. One solution to this
problem is to buy a sealed battery. Sealed batteries withstand heat
and cold much better than normal batteries, and they do not leak.
Sealed batteries cost a little more than regular batteries, but they also
last longer and come with better warranties.
Brake rotor warp age
Brake rotors warp from excessive heat. Routinely braking hard from
high speed, can cause warpage. Rotors have been replaced under the
new-car warranty. The extended warranties generally don't cover rotors,
since they are expected to be consumed with use. Many netters have had
their rotors replaced under warranty.
Suspension clunk
Cars produced prior to May 31, 1992 came from the factory with noisy upper
a-arm bushings. Your dealership will replace the bushings under warranty
with a modified part.
Cracking factory wheels
Some people on the net have noticed cracks where their spokes join the rim.
There seem to have been two manufacturers of stock rims, one type has a
curved area where the spoke joins the rim, and the other joins at a 90
degree angle. All reported cases of cracking rims have been on the 90
degree type rims.
Is my car normal?
Is my mileage unusually low?
The official EPA mileage ratings for the 3rd generation RX-7s is:
Manual transmission: 17 MPG City, 25 MPG Highway
Automatic transmission: 18 MPG City, 24 MPG Highway
Real world experiences from the net vary from this. A highly modified car
has gotten higher than EPA predicted mileage, but this is the exception.
Most people on the net get lower mileage, with 12 MPG in mixed city and
highway driving being a common number.
How much oil should my car consume?
The RX-7's engine consumes oil by design. It has oil metering pumps that
actually inject oil into the combustion chambers to be burned as you drive.
The amount you use will be determined by how aggressively you drive.
Sometimes my car backfires, is this bad?
No. Backfiring is caused by unburned fuel being ignited in your exhaust
system. Backfiring in itself, although annoying, is not harmful.
Excessive backfiring can be an indication of another problem.
What is typical 3rd Gen performance?
A typical, stock 3rd Gen should be able to turn about a 14.2 or better in
the quarter mile, and a low 5 second, or better, 0 to 60 time.
What are normal boost patterns?
According to the official Mazda test procedure, boost should be as follows:
- Drive to third gear with normal acceleration
- Accelerate from 35 MPH at WOT until passing 4500 RPM
- A slight and smooth increase in power should be felt at approximately 4500
RPM. This will be about 65 MPH.
Boost should be above 10 PSI up to 4500 RPM. The boost will drop to about
8 PSI just after 4500 RPM, and will begin rising towards maximum boost
depending on the length of time the throttle is held wide open.
Performance / Competition
I want to race/modify my RX-7. How do I start?
Before racing or modifying your RX-7, you should start with a healthy
car. Change your oil and filter, change your fuel filter, bleed the
brakes, change your air filter, make sure your tires are in good shape
and properly inflated. Use a little common sense and make sure your
car is in good shape BEFORE you add the additional stress of racing or
modification. This will also simplify any troubleshooting you may have
to do, as it eliminates some variables. When modifying your RX-7, change
one thing at a time if possible, this way you can more easily identify a
part that is causing problems. As always, this is not set in stone, for
example, you should not do anything that will dramatically raise the
boost pressure without also adding fuel. Use common sense.
From TurboRX7.com
im sure this is probly posted somewere but i thought id put it up .
Recalls
There have been three recall notices put out on the 3rd Generation RX-7s,
two pertaining to engine fires, and one concerning brake booster failure.
You will want to make sure that the car in question has had these recalls
done. If they have not been performed, you will want to take the car to a
Mazda dealership where they will be performed free of charge. If you don't
know whether the recalls have been applied to a car, you can call the Mazda
Customer Service line at (800) 222-5500 with the vehicle's VIN, and they
can tell you.
Coolant recall
The coolant recall involved the replacement of some cooling system parts
with stronger/more heat resistant materials and lowering the pressure of
the cooling system from 1.3 bar to .9 bar. The parts replaced were the
water pump seal, the water level sensor, the upper radiator hose, the
filler cap, the filler cap body, the thermostat gasket, the water hose
leading to the throttle body, and the water hose leading to the coolant
separator tank.
Fuel line recall
The fuel line recall involved replacing the fuel lines under the intake
manifold with lines made from a more heat resistant material, and adding
a fan control unit that runs the cooling fans if the coolant gets too
hot, even if the car is turned off.
Brake recall
The brake recall involves the replacement of a vacuum check valve and
hose leading to the brake booster. The original unit may stick when
oily and cold, preventing power assist under braking.
Common questions
What is the "exhaust system overheat" light for?
The "exhaust system overheat" light is connected to a temperature sensor
inside the car, under the carpeting, by the passenger seat. The
location of this sensor is just above the main catalytic converter, and
its purpose is to warn of excessive heat being generated by the converter.
When the temperature of the passenger floor reaches about 220 degrees F,
the ECU activates the relief air bypass and bleeds off air that would
otherwise go to the catalytic converter. This has the effect of cooling
the catalytic converter.
When I start my car, the RPMs go to 3000. Why?
All 1993+ RX-7s have what is called an "Accelerated Warmup System" that
revs the car up to ~3000 RPM when it is cold-started. Its purpose is to
heat up the 02 sensor and first catalytic converter to operating
temperature as soon as possible. If you don't like the thought of your
motor revving that high when cold, you can start the car in 1st gear
(with the clutch in), and the AWS will only take the RPMs to ~1500 or so.
It is also possible to bypass the AWS solenoid (see the performance section
of this FAQ).
What does the "mileage switch" do?
The "mileage switch" is in effect for the first 20k miles on a new RX-7.
It has the same effect as the "power steering switch". It adds some RPM
to the base idle to help keep the engine from dying.
What type of gas should I use?
The RX-7 requires "super" or "premium" unleaded gasoline. Use only
gas with a 92 or higher octane rating. Using leaded gas will coat
both your catalytic converters and your oxygen sensor, rendering them
useless.
What are some of the common problems with 3rd Gen RX-7s?
Common problems with easy fixes
Oil pressure gauge reads 0 psi
Sometimes the connection between the oil pressure sending unit and the
wire to the oil pressure gauge gets loose or dirty. The way to fix this
is to clean the metal tab on the sending unit with some 0000 steel wool,
and then re-install the gauge wire using some electrolytic silicone gel
(like some sets of spark plug wires come with) to seal out grime.
No boost above 4500 RPM
This is usually caused by a vacuum line coming off of the "Charge Control
Solenoid". The lines sometimes pop off while under boost. The solenoid
in question is located under the upper intake plenum. Look in your
shop manual on page F-10, the solenoid is item F. If a vacuum line has
come off here, trim off the end of the line where it has become loose,
and re-attach it to the solenoid. It is helpful to use wire-ties or
a dab of sealant to keep them from coming off again in the future.
Motorcycle shops also sell small, wire clamps that work well.
Hood squeaks / rattles
Squeaks: Lightly lube up the tops of the rubber hood stops and the latch.
Rattles: Tighten the latch mechanism so it holds the hood to the rubber
stops with light pressure. Latch rattles can also be temporarily fixed
by wrapping a small amount of tape around the latch where it mates with
the striker plate.
Hand brake light comes on while driving
The switch that controls the parking brake indicator light is located
under the leather brake handle boot. Sometimes during acceleration the
hand brake lever moves enough to activate the light. This problem can be
fixed by building up the area of the handbrake that contacts the switch
with a product like JB Weld.
"Low Coolant" alarm goes off
The "Low Coolant" alarm goes off when the low coolant sensor is not wet.
This sensor is located on the back side of the aluminum coolant fill
housing. Simply top off your coolant level to quiet the alarm (even though
it may already look full).
Radio flashing "Err" code
This means the factory radio's anti-theft feature has been triggered. It
can be reset by entering an unlocking code. The unlocking procedure is
at http://k-rad.com. Your dealership can also unlock your radio, but
they will usually charge a fee.
Other common problems
Hesitation at 3000 RPM when cold
No known cure.
I think it is caused by the double throttle control. Its purpose is to
prevent the engine from getting an overly lean fuel/air mix when you
first start to accelerate. Now the way this system works is that when
the engine is cold, (coolant below 175 degrees or so) the ECU opens the
double throttle control solenoid, which supplies vacuum to the double
throttle control actuator. This vacuum overcomes the spring tension
that normally holds the double throttle butterfly open, and it closes.
Now, think about what happens when you accelerate.... the engine pulls
less vacuum, and starts to go towards positive manifold pressure as you
build boost. With the vacuum going away, the plate returns to its
open (normal when engine warm) position. This helps explain why the car
doesn't hesitate when accelerating hard, and does when accelerating slowly.
The decision by the ECU to operate the double throttle control system is
affected by coolant temperature, and the current "map" that the ECU is
using. The Double Throttle control only happens during starting, cold
engine warm-up, and COLD engine with LIGHT LOAD operation. This map is
also affected by the 20k mile switch, which is why many people say that
the car never hesitated at 3000 RPM when it was new. The 20k mile switch
does the same thing that the EL switch does.... it adds base RPM to the
motor... which affects the ECU's decision as to what "map" it is currently
operating in.
This is just my personal theory, and may be wrong.
Paint problems
Some RX-7 owners have experienced problems with accelerated paint chipping
and fading. Mazda has set aside some money to deal with this problem on
a case-by-case basis. If your car has this problem, call the Mazda customer
service line (800 222-5500) and ask to schedule a meeting with your local
District Service Manager to have your paint inspected.
Battery death & leakage
Many people on the RX-7 mailing list have had their batteries die
prematurely. The main cause seems to be excessive heat. Batteries
don't do well with heat, and it gets quite hot under the hood of an
RX-7. Hot batteries also tend to leak acid. One solution to this
problem is to buy a sealed battery. Sealed batteries withstand heat
and cold much better than normal batteries, and they do not leak.
Sealed batteries cost a little more than regular batteries, but they also
last longer and come with better warranties.
Brake rotor warp age
Brake rotors warp from excessive heat. Routinely braking hard from
high speed, can cause warpage. Rotors have been replaced under the
new-car warranty. The extended warranties generally don't cover rotors,
since they are expected to be consumed with use. Many netters have had
their rotors replaced under warranty.
Suspension clunk
Cars produced prior to May 31, 1992 came from the factory with noisy upper
a-arm bushings. Your dealership will replace the bushings under warranty
with a modified part.
Cracking factory wheels
Some people on the net have noticed cracks where their spokes join the rim.
There seem to have been two manufacturers of stock rims, one type has a
curved area where the spoke joins the rim, and the other joins at a 90
degree angle. All reported cases of cracking rims have been on the 90
degree type rims.
Is my car normal?
Is my mileage unusually low?
The official EPA mileage ratings for the 3rd generation RX-7s is:
Manual transmission: 17 MPG City, 25 MPG Highway
Automatic transmission: 18 MPG City, 24 MPG Highway
Real world experiences from the net vary from this. A highly modified car
has gotten higher than EPA predicted mileage, but this is the exception.
Most people on the net get lower mileage, with 12 MPG in mixed city and
highway driving being a common number.
How much oil should my car consume?
The RX-7's engine consumes oil by design. It has oil metering pumps that
actually inject oil into the combustion chambers to be burned as you drive.
The amount you use will be determined by how aggressively you drive.
Sometimes my car backfires, is this bad?
No. Backfiring is caused by unburned fuel being ignited in your exhaust
system. Backfiring in itself, although annoying, is not harmful.
Excessive backfiring can be an indication of another problem.
What is typical 3rd Gen performance?
A typical, stock 3rd Gen should be able to turn about a 14.2 or better in
the quarter mile, and a low 5 second, or better, 0 to 60 time.
What are normal boost patterns?
According to the official Mazda test procedure, boost should be as follows:
- Drive to third gear with normal acceleration
- Accelerate from 35 MPH at WOT until passing 4500 RPM
- A slight and smooth increase in power should be felt at approximately 4500
RPM. This will be about 65 MPH.
Boost should be above 10 PSI up to 4500 RPM. The boost will drop to about
8 PSI just after 4500 RPM, and will begin rising towards maximum boost
depending on the length of time the throttle is held wide open.
Performance / Competition
I want to race/modify my RX-7. How do I start?
Before racing or modifying your RX-7, you should start with a healthy
car. Change your oil and filter, change your fuel filter, bleed the
brakes, change your air filter, make sure your tires are in good shape
and properly inflated. Use a little common sense and make sure your
car is in good shape BEFORE you add the additional stress of racing or
modification. This will also simplify any troubleshooting you may have
to do, as it eliminates some variables. When modifying your RX-7, change
one thing at a time if possible, this way you can more easily identify a
part that is causing problems. As always, this is not set in stone, for
example, you should not do anything that will dramatically raise the
boost pressure without also adding fuel. Use common sense.
From TurboRX7.com
im sure this is probly posted somewere but i thought id put it up .
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