|
| |
Symptom: Your 6 (or 12) volt bug sometimes doesn't
start, you have worn through the sole of your sneakers pushing the car to start
it and it is not "cute" anymore.
Before we start, this article requires that you either have
a decent understanding of current and voltage.
The "hard start" problem is most prevalent in 6 volt
Beetles, but can exist in 12 volt systems as well. In either case, you
should know that this "hard start" relay fix (detailed below) is a Band-Aid for
a less-than-perfect electrical system. I hesitate to even mention it. I am a
purist and believe that things should be left "as they were" and kept in
pristine condition through your dedication and loyalty. But I also know that on
a cold December night, when you just want to get home and the snow is starting
to stick, I can take my "dedication and loyalty" and shove it. I would say
though, that you shouldn't do this for 12 volt systems as whatever problems that
are causing it are much more easily fixable than with the 6 volts systems.
How it is Supposed to Work
You turn your key and
electricity from your battery goes to your starter, which is just an electric
motor, and it spins the engine. Any questions? At the high level, it is
really that simple. The problems comes in the way the electricity is delivered
to the starter. But before we go there, lets make sure we understand how a
starter works.
We have already established that it is just an electric
motor, but there are two other things attached to it that you should know about:
Gizmo #1: The "bendix".
For some reason I think "bendix" is one of those old words that you only hear
your grandparents use. Like "housecoat" or "rubbers" (those rubber things that
you supposedly put over your shoes when it rained). But most seasoned mechanics
still call it that. The bendix is an electromechanical device that slides the
little gear on the end of the motor shaft out so it can mesh with the teeth on
the flywheel. It is attached directly to the starter. Without a bendix, the gear
would have to be engaged on the flywheel all the time, even after the engine was
running, and would make that noise that your grandmother's car makes when she
"restarts" the car after it is already running (a noise that could bring your
grandfather out of a coma).
Gizmo #2: The "solenoid".
The solenoid is pretty much another name for "relay" in the case of the starter.
It is actually an electromechanical device that pulls a set of contacts together
to make the high current connection between the starter and the battery.
Ever hear someone crank a car until the battery dies? Errrr,
errrrrr,,er,,er, then just "click....click" as they turn the key? That "click"
is the bendix/solenoid working but there is not enough juice left to actually
turn the engine over.
Now in most starters the bendix and the solenoid are the
same electromechanical device. "Electromechanical" means that it takes
electrical energy and makes mechanical movement out of it. The
same coil (that produces a strong magnetic field) that throws out the gear, also
pulls together the contacts. Cool, huh?
Lets talk about what a relay, and in the case of the
starter, the solenoid does. Such a device allows a small amount of current to
switch a much larger amount of current. The starter in your Beetle is, by far,
the highest current device. Much more than the headlights, rear window
defroster, radio, etc. all put together Starters can pull in excess of 100 amps
from the battery; but fortunately for the battery, only for a brief period of
time. Notice how fat that wire that goes from the battery to the starter is? You
wouldn't want to pull that huge wire all the way up to the dash where the
starter switch is and back again to the starter. One, it would be very
cumbersome, and two, your starter switch could never handle switching that much
current. That's what the solenoid does for you. It keeps that very high current
circuit as short and direct as possible, just between the battery and starter.
So when you turn your key at the dash, you are actually
applying battery voltage to the solenoid, which is then throwing the gear out to
the flywheel and making a direct contact between the battery and starter
via that big, fat wire.
That is how it is supposed to work.
Problems with the Starting Circuit
Relatively speaking, that solenoid itself, is a pretty high
current device. I don't know for sure, but I bet it is in the 10 amp range for
the 6 volt systems. So that circuit, from the battery to the dash,
through the ignition switch and back to the solenoid, is a pretty high current
one. This means that it is very susceptible to voltage drops. And the solenoid,
especially after it is 30 years old, is pretty picky about voltage. Loosing 1
volt out of 6, and that coil just ain't gonna pull. Sometimes you hear about a
"hot start" problem. Poor connections, as a result of corrosion, may drop
varying levels of voltage depending on the temperature of the connection. And
remember that passing current through a corrosive, resistive connection
generates heat in that connection.
The "hard/hot start" problem is usually based in the
solenoid (secondary) circuit, not the high current starter (primary) circuit.
But don't overlook the obvious other connections (see below)
Here is some text and graphics describing the various
starter circuits over the years.
1954-August 1959
In most of the 50's model
years, the circuit was the same as the '61-'65 below, except that the
connections to the headlight switch and fuse box were after the ignition
switch (not shown here). From a current optimization (to the starter)
standpoint, that made the most sense.
August 1959-1965
The dash is fed by a big red
wire that comes straight off the regulator on the generator and goes directly to
the light switch, from a "shared" terminal on the light switch, this wire goes
to one of the fuses and from that same side of the fuse, it also goes to the
ignition switch. A black wire goes from the ignition switch to another fuse, but
from that same (unfused) side of the fuse, a black wire goes back to the
ignition coil. NOTHING in this whole starting and ignition circuit is fused! Be
careful. Another red wire comes off the ignition switch and travels all the way
down back to the starter solenoid.
Note that this secondary starting current path "touches"
many components unrelated to the starting circuit (headlight switch, fuse box),
but doesn't actually go through them. This is just done to optimize the wire
path and provide voltage to other stuff along the way. Unfortunately though, it
provided more connections for potential voltage drops.
1966
A fat red wire comes right off the starter lug that the
battery wire is connected to and goes straight to the ignition switch. The
"start" lead from the ignition switch then goes to a fuse end, from that same
side, it goes to the headlight switch, "through" the headlight switch via
another tab to the generator lug, then to the solenoid connection on the
starter. This "moved" the ignition switch a little farther ahead in the circuit,
but the switched lead than still had to pass along the headlight and generator
circuits before getting to the starter.
1967-1968
The 12 volt system(s). They finally got it right. A lead came right off the
battery, to the regulator (now located under the back seat), then up to the
headlight switch, then to the ignition switch and then straight back to the
solenoid.
1969-1971
Almost the same as above except the current passed
"through" the headlight switch (in one terminal, out another; instead of
"piggy-backing" the same terminal) before going to the ignition switch.
After '71, the wiring diagrams got too complicated for me
to follow anymore.
Stuff to Check First
Before you go running out to buy a relay, you should
definitely check out your whole starter wiring circuit. First, the starter
itself.
Most Beetle starters actually supply the voltage to the
solenoid via the starter armature. This means that dirty or worn starter motor
brushes can cause the intermittently dead starter problem too. It is really not
all that hard to take the whole starter out and do a quick clean up on it. It
may cure the problem all by itself. To do this, remove the starter from the car
and remove the end cap on the starter (the end opposite the gear) by taking out
the long bolts and remove the end cover. Clean up the brushes (a can of carb
cleaner works well) and make sure that they are not worn down so much that they
aren't making contact with the armature commutator. Replace them if necessary.
Clean the commutator with a fine emery cloth or sandpaper (the copper
"strips" on the armature shaft that the brushes ride on). Clean the thin slots
between the commutator pads using and old toothbrush. Put some grease on the
armature shaft end prior to re-assembling the end cover and some on the snout of
the starter (shaft in front of the gear) before putting it back in the tranny.
Now, I can't possibly cover all of the details of all of
the years of the Beetle's wiring (some in the diagrams above), so let me make
some generalizations. In the list below, "good" in terms of connections, means
clean, shiny and tight. Some connections are big eyelet, stud and nut type; many
are .250" "spade" push ons; and some of the very old VWs had tiny screw
terminals on everything. Get some fine sandpaper or emery cloth (I have a
little, cheapy, rechargeable battery powered "Dremel" type tool, that turns much
slower than a Dremel and takes all of the 1/8" shank accessories. I use it a
lot for cleaning up contacts) and make sure that all of your metal contacts
look like metal. Remove all corrosion and rust. Sometimes those female
push on connectors get loose and you need to slip them off and squeeze them down
a bit with some pliers to make them push back on snug. Sometimes you will need
to replace connectors that are useless.
And let me diverge and talk about wire terminations in
general. I am a bit fanatic about this. I do not believe that anything less than
what I do is futile, but I do ALL of my wire terminations the same way: solder
and heat shrink. I don't crimp anything. Yeah, I have the crimp tools and all,
but something in my mind says that stripping a wire, slipping it into a barrel
ended crimp type connector and then flooding the cavity with solder is the
best way. A piece of heat shrink over the outside of the barrel, and a
bigger one shrunk around the whole outside of the female push on, is what I do.
Takes more time, but I feel better about it.
So here's what you should check:
- Your battery terminals. Very often
overlooked. Go buy one of those $2 battery terminal post cleaners and clean up
the posts and the terminals, both of them. But leave the ground
one disconnected until you have done ALL of the work on you electrical system.
- The rest of the primary starter
circuit. Follow those fat wires to where they go. The big fat red one usually
goes right to the starter and is held there by a big eyelet and lug. Might be
a bit difficult to get to, but crawl under and reach up. You might want to
replace that cable; you can usually find them at your favorite local
department store in a usable length. Make SURE that you have disconnected the
battery ground when you do anything with this wire. It is not fused and if you
short it you will get a crash course in welding and fire prevention. Also
check the battery ground. It is usually either a fat black wire or a webbed
copper strap and must have a very good, clean connection to the body of the
car. Remember that current for everything passes through this cable. It
should be the fattest pipe in the whole circuit. But leave it disconnected
from the battery until you have everything back and are ready to test it out.
And lastly, the starter ground.
"What starter ground?" you ask? Well, let's see, the starter is metal and it is
bolted to the tranny, what could be a better ground than that? Well, what is the
tranny bolted to? Rubber engine mounts, duh! Yes, the tranny must be
grounded. Usually this is done via one of those braided copper straps up on the
front tranny mount. It goes between one of the tranny-side bolts and one of the
body-side bolts. It is subject to lots of abuse riding along under the car, all
exposed. There has been much wailing and gnashing of teeth for overlooking this
one.
- The secondary circuit. Now this is
where the variances between years comes in. In the older models (most all 6
volt) a thick (about 8-10 gauge) red wire carried voltage up to the dash and
basically powered everything else (refer to the diagrams above). In some
years, this wire came right off the battery under back seat, in others, it
came from the voltage regulator mounted atop the generator back in the engine
compartment. Then it either went straight to the headlight switch or it went
to the fuse panel. But in all models, there is one main "feed" wire that
supplies power to all non-starter devices. It is usually pretty easy to spot
as it is thick and red. In 12 volt systems, it comes right of the regulator
under the left side of the back seat. Check the connections that this wire
makes at either end. They must be shiny, clean and tight. [In my '68s
and '67, I spliced a blade-type fuse holder into this wire right off the
battery. I think I used a 50 amp fuse in there. I never liked the idea of such
a fat wire running unfused off the battery. You can get these high current
fuses and holders a most auto parts stores]
- Connections to the ignition switch.
In the "metal dash" years ('67 and older), this is pretty easy as the back of
the switch is easily accessed. But on the newer ones, it is embedded in the
steering column with the turn signal/hi-beam switch, and it may seem a bit
more complicated. Just look for that bundle of wires coming out of the
steering column and up under the dash. You should be able to sort out the turn
signal, hi beam and ignition switch ones by looking where/to what they go.
Again, good, tight, shiny connections are needed.
- The ignition switch itself. I have
had these go intermittently bad in my cars. The switch itself is actually a
separate component of the key mechanism on most newer ones, and should still
be readily available. A real simple way to rule out the switch as the culprit
is to just jumper it behind the dash at "that time" when the car won't turn
over. Just use a good 14 gauge or better piece of wire. Jump from the "hot"
side of the switch over to the terminal, which goes down back to the solenoid.
If it kicks over that way, but not when you turn the switch, it is probably a
bad switch. Oh yeah, make sure it isn't in gear when you do this.
Another good way to trouble shoot the whole secondary starting circuit is to
eliminate it by bypassing it with a jumper. If the car doesn't start and the
battery seems to be good, make up a fat jumper wire (I have a few with some big
alligator clips on the end) and jump between the positive terminal of the
battery and the solenoid terminal on the starter. In doing so, you will have
eliminated the entire secondary circuit with your jumper wire. If the engine
turns over, you have verified that there is a problem (disconnect or voltage
drop) in the secondary circuit. If it still doesn't, either your starter is bad,
the battery is dead (even with a very weak battery, you should hear the bendix
clicking) or the ground path between the battery and starter is bad (battery
ground, starter ground).
The "Hard Start" Relay
Ok, so you thoroughly checked out the whole ignition
system and if your starter leaves you stranded one more time you are probably
going to do some irreparable damage to your Beetle.
We already have two circuits to talk about in the stock
system:
The primary starting
circuit. This is the 100-or-so amp, fat wire directly between the battery and
starter, and the battery and starter grounds.
The secondary starting
circuit. This is the 10 or so amp circuit from the battery to the ignition
switch and back to the solenoid.
The "Hard Start" relay is about placing a new relay in the back seat/starter
area and creating a third circuit. This new circuit would allow the
ignition switch to only have to switch a low current relay, which in turn would
switch the solenoid, which in turn switches the starter. It may sound a bit
kludgy, but it does work. Rather than keeping up a voltage drop plagued solenoid
circuit, you can greatly reduce the current through your "front to back" path
between the starter switch and the starter by installing this relay. These
relays will usually draw l amp or less. And remember, voltage drops are directly
proportional to the current through the circuit; the less current you draw
through a circuit, the less susceptible you are to voltage drops.
A simple relay has 4 or 5
contacts and is represented by this:
The "coil" connections are where you apply voltage to make
the relay close it's contacts. The relay doesn't care which one you ground and
which one you apply 12 volts to, it will work either way. [unless you find one
of those old metal cased kind where one coil wire is tied to the metal case and
hence to ground]
The contact terminals do just what the graphic indicates;
when the coil is energized, the magnetic field pulls the moving contact down.
Some relays have a "normally on" contact meaning that it makes contact while the
coil is not energized, and breaks contact when it is. You won't use this
connection on the relay if it has one. Most relays will have a graphic similar
to this on the packaging.
Here's how you hook it up:
- First, disconnect the ground from
the battery, if you haven't already
- Figure out where and how you are
going to mount your relay. My suggestion is under the back seat somewhere.
- Disconnect the wire from the
solenoid connection on the starter, this would be the smaller wire. Bring
that wire into the back seat area and connect it to one of the "coil"
terminals on the relay. If you have an old metal cased/grounded relay, this
wire should go to the "+" of the coil.
- Ground the other "coil" terminal of
the relay. You will have to make up a wire for this, a small eyelet secured
with a sheet metal screw into some body metal is best. But not into the floor
(will start rust). You might also use a nearby body bolt.
- Now connect one of the contact
terminals goes to solenoid terminal on the starter. You will need to make up
another wire for this and this should be at least 14 gauge.
- Lastly you will need to connect the
other contact terminal to a battery source. You can tap right off of the
battery's positive terminal, or from the "hot" (large) lug on the starter.
Some preparation work will pay
off. After you read these steps, go scope out the whole deal in your car if you
are going to do it. Take some measurements, then go buy all the stuff. You will
need to find a 6 volt relay, and these may be a bit hard to find. The contacts
should be rated for at least 10 amps at 12 or 6 volts DC (if the max contact
amperage is rated at a higher voltage, it should still be at least 10 amps). Get
the wire that you need. You need to make up:
1) a ground
wire for the relay coil;
2) a wire to go
from the relay to the solenoid and
3) a wire to go
from the relay to a power source.
Buy the connectors that you need, most relays have the common
1/4" push on terminals. Heat shrink tubing will make for a nice installation and
a soldering iron is needed too. When you are done, it should look like this:
And that is really all there is to it. Again, this is a Band-Aid, but one that
many 6 volt VWs lived with for many years. It does work on the 6 volt
bugs, but it really is not needed on the 12 volt ones. The problem is not nearly
as common on the 12 volt Beetles and just getting all of the circuits clean and
tight will almost always fixes the problem.
|
