NWICC Tech Tips December 2006
“Service Column Lock”. This message displayed on the drivers
information center (DIC) has plagued some of our members on more than one
occasion with their C5’s. As originally designed the steering column lock was
an anti-theft feature. Since the ignition switch is in the dash, the C5 is
programmed so that if the column lock does not unlock when the engine is
started the fuel will be shut off as soon as the car reaches 2 mph. This is to
prevent you from driving off with the steering wheel locked. All C5 automatics
from 97 thru 2000 and 6 speed cars from 97 thru 04 have this system. GM did not
install it in the later automatic trans cars (after 2000), probably due to the
number of problems experienced. It was
found that low battery voltage or a power interruption to the body control
module (
There have been several
recalls by GM to address this problem. One involved the installation of a relay
in the automatics to insure the fuel shutoff. This was the infamous K-harness.
The 6 speed cars were to be reprogrammed to insure fuel shut off as well. None
of this addressed the problem of the steering column locking up, but it did
cover GM’s liability in case of an accident.
The K-harness proved to be unreliable and in some cases would shut off
fuel even if the column was not locked. The 6 speed programming proved to be
problematic as well. Both could leave you stranded needing a flat bed for towing.
Also, GM’s 6 speed reprogramming would remove any custom tuning i.e. Predator,
Hypertech, dyno tuned, etc. In some cases, especially after a dead battery, the
column lock and
GM’s latest recall, which is
good until 2008, involves removal of the steering column lock plate on both
automatic and 6 speed cars so the steering wheel cannot lock up because there’s
nothing there to lock. Problem solved.
See you at the track,
Bill
Porter
NWICC
Tech Tips
December 2005
Now
that the season is over, the question of how do I store my Vette for the winter
months comes up from some of our members.
First
you need a car cover. For inside storage any cover made of all cotton will do. There
are also covers on the market made of the new miracle fabrics that breathe.
Stay away from cheap plastic covers. They cause the paint to sweat and can
cause damage and discoloration of your car’s finish. The important thing is
that the cover you choose is made of a breathable fabric.
There
is no need to remove the wheels and tires or place the car on jack stands. Any
flat spots that develop in the four months of storage will “drive out” within
the first few miles of driving in the spring. You may want to place the tires
on carpet or plywood squares to insulate them from the damp concrete.
The
fuel system also needs some attention. Fill the gas tank and add a gasoline
stabilizer such as “Stabil”. This will prevent the gas from breaking down and
forming gum and varnish which will cause you to have to replace fuel injectors
in the spring.
The
battery in your Vette is subject to a constant drain due to the computer and
microprocessors. Disconnecting it is one solution, but you loose all your radio
presets, security codes, seat memory, etc. A better solution is to invest in a
battery “float charger”. Float chargers allow the battery to discharge slightly
and then kick in to bring the battery up to full charge, unlike a trickle
charger which constantly charges and can boil away the water/acid in the
battery. Just plug it in, hook it up and forget about it – they’re cheap too.
Finally
leave the windows cracked slightly for ventilation. On a monthly basis start
the car and let it run long enough to bring the temperature up and move it
around some. This prevents the engine and transmission seals from drying out
causing leaks.
See you at the track,
Bill
Porter
NWICC Tech Tips
March 2005
One of the most popular and
usually the first modifications that C4 and C5 owners make to their Corvettes
is an upgrade to the exhaust system. The choices on the market are almost
endless. Most owners’ choice is based on appearance and sound quality. There
are other factors to consider before spending big bucks on a new system.
Some owners start out by
replacing the stock exhaust tips with larger polished stainless tips. This
helps with the appearance of the rear of the car and we all know that the pipes
exiting the rear of C5’s are way too small to be on a Corvette. Unfortunately
this doesn’t do anything for the sound. A Vette should sound like a Vette!
What’s needed is a good “cat – back” exhaust system. Cat – back refers to a
system that starts at the rear of the catalytic converter and includes exhaust
pipes, mufflers, and tail pipes.
Sound quality is in the ear
of the beholder. Whether it be a mellow rumble or an
all out race sound, the choice is up to the owner. The aftermarket manufactures
have a system to please everyone. Before making a choice, try and find another
owner who has the system you like on their car. If possible, take a ride with
them so you can evaluate the amount of interior resonance with the system. Some
sound great on the outside but are difficult to live with inside the car at
cruise speeds. Some C4 systems are notorious in this respect.
Tubing size and material is
another consideration. “Bigger is better and stainless won’t rust”. Don’t
forget to use stainless clamps when installing the new pipes and keep in mind
that stainless has a tendency to slip out of alignment if not properly clamped.
But nothing looks better than a polished stainless exhaust.
C5 owners might also want to
consider installing an X-pipe with their new system. An X-pipe is a type of
crossover that evens out the exhaust pluses, increases flow and helps to
eliminate that “rattle” you hear with some systems at idle and cruise speeds.
Performance wise you can’t go
wrong. No matter what style, be it straight thru or baffled, targa style or
mufflers; aftermarket looks better, sounds better, flows better, and produces
more horsepower than stock GM.
See you at the track,
Bill Porter
NWICC Tech Tips
May 2003
Some of our members have
recently had questions concerning wheel and tire upgrades on their C4
Corvettes. Should you go from 16” to 17 or even 18” wheels? What size tires
will fit? Do you have to use adapters or spacers? Will the wheels clear the
brake calipers? What about fender clearance? Will the tires stick outside the
body? Considering the number of combinations available there is no simple
answer to these questions.
First of all Corvette went to
larger wheel and tire sizes for one reason and that was to put more rubber on
the road…… more rubber - better traction and handling. All C4’s use the same
size bolt pattern so different years can be interchanged with some limitations.
1984 thru 87 Corvettes came with 16” wheels, 1988’s had both 16 and 17” and
1989 thru 96 were all 17”. The difference is in the wheel offset. 1988 thru 96
wheels, all interchange with no problem. If you put 1988 thru 96 wheels on an
earlier model Vette they will fit, but
the tires will sit inside the fender by about an inch instead of being flush
with the fender edge. Also brake clearance may be a problem. There are adapters
/ spacers available to correct this problem however they can be a problem
within itself. Each adapter has 5 lug nuts, so what you end up with is 20
additional lug nuts to worry about loosening up.
If you decide to go with 17”
wheels on an 84 thru 87, the best bet is to go with an aftermarket reproduction
wheel. These are available with the correct offset and in a variety of styles
including ZR-1 and Z06 styles in polished and chrome. Tire size should be the
same as what originally came on that wheel. Hope this answers some of your
questions.
See you at the track,
Bill Porter
NWICC Tech Tips
February 2003
Although we’re still in the
middle of winter and our Corvettes are, or should be, under wraps in the
garage, this might be a good time to look at one of
the problems many of us experienced last summer. Overheating or cars running
too hot was a major concern of many of our members. The first thing to consider
is the condition of the cooling system. Is the system clean? Has it been
flushed and refilled with a 50/50 mix of antifreeze and water? Do not run straight antifreeze or just water!
Next take a look at the
radiator and check for debris, dirt, leaves etc. in this area. Corvettes are
like vacuum cleaners, anything you drive over in the road is likely to be
sucked up in the radiator. One of our members, who I won’t name, couldn’t
figure out why his car started to run hot until he discovered a sheet of
notebook paper plastered against the radiator.
Corvettes come from the
factory with 195 degree thermostats. This causes the car to run 210 – 220
degrees and even hotter with the A/C on. This was done to decrease exhaust
emissions, but the cost is less power. You might want to consider changing out
the thermostat for one rated 160 degrees for summer or 180 degrees if you drive
your Vette during the winter. Also, C4 and C5 Corvettes have electric cooling
fans that are programmed to come on at about 228 degrees. Reprogramming the
computer so these fans come on around 185 and off at 175 degrees in combination
with the thermostat change will produce a cooler running engine and an increase
in power. 84-93 C4s can be reprogrammed by installing a custom PROM (Chip);
94-96 C4s, and C5s require use of a Power programmer. Stay cool.
See you at
the track,
Bill Porter
NWICC Tech Tips
January 2001
Ok…you’ve installed a high
performance chip, changed the thermostat to 160 degrees, and installed a low
restriction and better sounding exhaust system from the catalytic converter
back to those shiny polished stainless tips………..What next?
While the Vette’s down for
the winter, how about doing some improvements to the intake side of the engine?
Installing a K&N air
filter is the first place to start.
Next, how about ram air.
There are several systems on the market; one is a reverse flow system that takes
cool intake air from the radiator cavity rather than hot air from under the
hood, and another takes cool air from under the front end just forward of the
radiator. Both systems work, but be careful with the
latter if going through deep water…. but who does that anyway. The least you
should do is replace the stock air cleaner lid with a low restriction cutout
unit. You can do the modification yourself or they are available pre-cut in
stock black or chrome from several aftermarket sources.
While you are at it, you
should relocate the
Next, take a look at your MAF
sensor; there are two screens on the front and rear of the sensor to prevent
debris and curious fingers from contacting the internal components. Some racers
remove both screens to increase air flow through the sensor. For a street car,
remove only the rear screen, this can easily be done with a pair of needle nose
pliers, but be careful, MAF sensors are expensive.
See you at the track,
Bill Porter