Virtual Mechanic

Warning
Extreme care must be taken when jump starting an engine or serious bodily injury or damage to the vehicles may result.

If jump starting is not done correctly, expensive damage can be done to a vehicle’s electrical system, particularly to those fitted with electronic ignitions. Check the vehicle operating manual, if there are no specific instructions, then follow these steps.

When jump started, flat batteries generate high volumes of hydrogen gas which is extremely explosive, so sparks and naked flames must be avoided at all times. Do not lean over batteries during the operation. As a precaution, wear safety goggles and a face shield to protect eyes.

First, check to ensure both batteries are the same voltage (6 or 12 volt) and that the two vehicles are not touching each other. If the failed battery is open circuit do not attempt to jump start.

* Open circuit batteries can be detected by:

battery volts reading zero immediately after a high rate discharge test is applied.
when the battery will not accept charge current.
Carefully follow these steps in order:

Warning: Jump starting can damage vehicle electronics. Check the vehicle operating manual. If there is no specific instructions then follow these steps. If the failed battery is open circuit* do not attempt to jump start.

Step 2

Be sure the batteries of both cars are the same voltage (6 volt or 12 volt).
Drive the donor car close to the disabled car but ensure that the vehicles are not touching.
Place both cars in neutral or park and apply hand brake.
Make sure both vehicle ignitions are switched to OFF and all electrical equipment is OFF.
Step 3

Connect the vehicles in the following EXACT sequence and make sure the jumper leads are clear of any moving parts.

Take the RED jumper lead and connect to POSITIVE terminal (marked + or POS) of the discharged battery.
Connect the other end of the RED jumper lead to the positive terminal of the charged battery.
Take the BLACK jumper lead and connect one end to the NEGATIVE terminal (marked – or NEG) of the charged battery.
· Make the final connection to the engine block or chassis of the stalled vehicle (negative earth vehicles only). Never use Air Conditioner, Brakes or Fuel Lines for engine earth.

Step 4

Start the engine of the stalled vehicle.

Step 5

After starting, allow engine of the stalled vehicle to fast idle for a minimum of 10 minutes before disconnecting the jumper leads (see step 6) to allow the cars electrical systems to balance. This reduces the possibility of damage to vehicle electronics.

Step 6

Remove the BLACK cable first from the vehicle with the discharged battery then the opposite end from the charged battery. Repeat for the RED cable.

Step 7

After your car has been jump started, the battery should be recharged with a battery charger.

ELECTRICAL SYSTEM

Charging system – Alternator to the battery lead

PURPOSE

The purpose of the lead from the alternator to the battery is to supply the power from the alternator to the battery.  This charging power is good for at least 5 to 10 years.  After this time the cable may become hardened or the connections may be creating a resistance.  All this means is a power voltage drop between the alternator and the positive battery terminal.

THINGS TO LOOK FOR

The best way to check the power from the alternator to the battery is to get a Multimeter.  The first check is to check the power across the battery, the positive and negative pole, and then compare that to the power from the positive terminal at the rear of the alternator to the power across the battery terminals.  If the power is showing a difference then this is an indication of a voltage drop or a bad cable connection to the alternator. 

IS IT EXPENSIVE TO REPAIR?

It is an inexpensive repair.  Purchase some heavy duty 15-20 amp cable and make sure that it is long enough so that when the engine revs the cable still has plenty of slack.  So make sure when fitting this cable that it doesn’t interfere with any other component as if it does wear against any other component it may short out the whole electrical system.  Make sure the terminals are soldered on each end and connect the cable from the positive alternator terminal to the positive battery terminal and measure the volts across the battery and the negative battery pole to the positive alternator terminal and they should be the same.

ELECTRONIC FUEL INJECTION [EFI]

Relay

PURPOSE

The EFI relay is a heavy duty electronic switch that requires very little voltage to switch on at the same time  It may connect a moderate amperage circuit without the switch wearing out.  It is also designed to disconnect if overloaded.

THINGS TO LOOK FOR

The EFI relay is an important switch that rarely goes wrong as most relays are reliable for approximately 10 years.  After this time they may start to develop intermittent problems, eg cutting out.  Also when the relay cools down the engine may start up.  To check this suspect relay by swapping with another.  You may find a row of relays and take a note of what they are connect to, eg the air, fan or pump, provided the relay is the same amperage and shape as the air or fan then it may be swapped.  If this makes a difference it just needs to be replaced.

IS IT EXPENSIVE TO REPAIR?

The average relay may cost around $10.00-$20.00 depending on the make.  If it is a tachometric relay it may cost around $30.00-$80.00.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT

If you are stranded and have a suspect relay swap it or bridge it just to get you home.

Recently have you noticed that when you shop around at different suppliers or stations that some times you seem to get more per km. Well I have decided to conduct a simple test over the next month. My plan is to choose the major fuel outlets to see if I can get more per km  or if they are all the same. Now don’t let me do all the hard work, if you wish to participate join me and offer your experience.