Serving the Gainesville and Hawthorne Florida Area
WE will diagnose a no start or no spark condition from free to $100-$200
It depends on diagnostic time
(Prices good for most cars and trucks)
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All gasoline engines need good spark to run
All gasoline engines have spark plugs which ignite a fuel / air mixture. This burning fuel propels the vehicle down the road. A gas engine MUST have good spark to run. About half of engine failures (car won't start) are from spark failure (no spark, or no "fire"). The ignition coil takes a low voltage (12 volts on most vehicles) and multiples it into thousands of volts. (low voltage won't make a good spark. High voltage does.) Older vehicles had coils that put out 8000 volts or so. Modern vehicles have colds that produce 20,000, even 50,000 volts.
types of coils and ignition systems
Ignition systems on older vehicles
Older cars had ignition systems consisting of a single coil, and a distributor cap and rotor that "disributed" the spark to the different cylinders. The distributor also had points at first, and later an electronic pickup coil to operate the coil, via an ignition module.
Computer Controlled ignition systems
When car engines started to be computer controlled, at first they used the same distributor/ rotor/coil setup. Later, they moved the ignition pickup coil to the crankshaft, and the distributors didn't have anything in them besides the rotor. Other vehicles (like Honda) had a distributor, rotor, pickup coil, and ignition coil all in one package. The next step was getting rid of the distributor, and firing coil packs directly from a module controlled by the computer. These cars have 1/2 the number of coil packs as they have cylinders. (A 4 cyl will ahve 2 coil packs, a V-6 will have 3, and a V-8 will have 4) Each coil pack will fire 2 plugs at the same time: one cylinder will be on the exhaust stroke, the other on the power stroke) The newest engines have a coil for each cylinder, often a small coil which sits on top of the spark plug. Each coil is controlled directly by the computer.
TESTING FOR SPARK!!! (COULD BE DEADLY if you have a pacemaker, otherwise unpleasant if you get a shock: careful now!!!)!!!
Remove a spark plug wire. They sell spark testers at any parts store, fairly reasonable. (Follow the directions: don't ground to the battery! It will explode! Otherwise, Insert a screwdriver or other metal object in the plug wire end. Hold this wire about 1/8 to 1/4 inch from a metal part of the engine. Have the friend turn the motor over. (making the rrrrr sound like you were trying to start the engine).
There should be a nice blue spark jumping off the screwdriver to the engine metal part (pick a part: any part).
DON'T LET THE SPARK GET NEAR THE BATTERY: IT WILL EXPLODE!!!!!!!!!!!!!!!!!!!!
CAREFUL!!!! IT CAN BITE!!!!!!!!!!!!
No spark can be from a bad coil, rotor, distributor cap , electronic igniton module, pickup coil assy., or wiring defect.
Bad Coil symptoms and repair
No spark: total coil failure
A coil in total failure is easy to diagnose. There is a positive and a negative side of the coil. If there is no spark from the coil, disconnect the two wires that feed the coil, and connect a test light between them. Turn the engine over. The test light should blink on and off. If the test light blinks on and off, but the coil when connected makes no spark the coil is bad.
Coil resistance tests A coil can be checked with an ohmmeter. A typical good coil will measure .6 ohms or so on the primary side, and 8 K Ohms on the secondary side.
On any car, especially a new one, a coil can be bad and still make spark. A good repair manual will have resistance specifications for the primary and secondary coil windings, but sometimes these can mislead you. At one dealership I know, the mechanics take all the plug wires off and spin the engine over. A fireworks show of 3 inch bright blue sparks should arc across the coil teminals on the coil pack, enough to scare you if you're not expecting it. Those are good coils. A wimpy yellow spark that's not that frightening: the coil or coils are bad.
Marginal coil symptoms
When a coil starts to go bad, but hasn't totally failed, it can be hard to diagnose. Sometimes it will run fine, then it can act like it's running out of gas, and then run fine again. As a coil heats up, the internal resistance increases, so a bad coil can start to fail when it heats up, and the run OK when cold.
Auto, Car, and Truck Article List
ABS: Anti-Lock Brake Systems
ADVANCE: Car ignition timing
ALTERNATORS and Car Battery
BAD CAR DESIGNS
Bad Drivers: How NOT to drive
BATTERIES: Auto, Car or Truck
BELTS AND HOSES
BODY AND BUMPER REPAIRS
BRAKE REPAIRS: Car or Truck
Car Washing and Care
CARBURETORS:Car & Truck
CHECK ENGINE LIGHT
CLEANING: Engine Cleaning
CLUTCH REPAIRS: Car & Truck
COMPRESSION: Car Engine
COMPUTER CAR CONTROLS
CRUISE CONTROL / LANE GUARD
CV JOINT OR CV AXLES
ELECTRIC WIRING REPAIR
ENGINES: Car & Truck
FILTERS: OIL, AIR, ETC.
Flywheels, dual mass flywheels
FUEL AIR MIXTURE
FUEL INJECTION: Car & Truck
FUEL PUMPS: Car & Truck
GAGES AND "IDIOT LIGHTS"
GASKETS AND SEALS
GLASS: WINDOWS AND WINDSHIELDS
HEADS & HEAD GASKET
HOSES AND BELTS
"IDIOT LIGHTS" AND GAGES
IGNITION TIMING: Car & Truck
AUTO JACKS: lifting cars safely
LEAN "Car runs lean"
LIGHTS: WARNING OR "IDIOT LIGHTS"
Limp Home Mode
NO START: Car Won't Start
OIL: What's right for your car?
OIL LIGHT ON OR GAGE LOW
RADIATORS: Car and Truck
RICH: Car runs rich
SEALS AND GASKETS
SELF DRIVING CARS / CRUISE
SERVICE ENGINE SOON LIGHT
STARTERS: Auto, Truck
TIMING: IGNITION TIMING
TIMING BELT & TIMING CHAIN
WARNING LIGHTS OR "IDIOT LIGHTS"
Car Washing and Care
Washing and cleaning your car
WATER PUMP REPAIR
WINDOWS AND WINDSHIELDS
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