Oily spark plug,changed plugs now car smokes

Remove a spark plug and inspect. If there are fluffy, dry carbon deposits, it's probably too much fuel, and I'd suspect a leaking fuel injector. If the plug is wet and oily, that usually indicates a failed piston ring or (sometimes) a blown head gasket, and you'll probably need a replacement engine (rebuilt), which may not be worth it.
One long shot: I had a truck where the oil pressure sensor would periodically start leaking and drip oil onto the exhaust pipe near the engine. When the pipe got hot, clouds of black smoke would start coming out the back when I was driving.

Error Code: P0300
Description:
Random/Multiple Cylinder(s) - Misfire Detected
Problem Area:
Air Intake System leaking.
Fuel Supply faulty.
Injector(s) faulty.
Ignition Cable(s) and/or Spark Plug(s) faulty.
Ignition coil(s).Exhaust Gas Recirculation (EGR) Valve stuck/open.
Camshaft Position Sensor faulty.
Low compression.
Wiring.

Solutions:
Check Misfire Recognition.
Check Air Intake System.
Check Fuel Supply.
Check Injector(s) and Injector Sealing.
Check Ignition Cable(s) and Spark Plug(s).
Check Ignition Coil(s).
Check Exhaust Gas Recirculation (EGR) Valve .
Check Camshaft Position Sensor.

Some diagnostic readers give out cam sensor instead of crank sensor codes problem is what you have not changed .The crankshaft sensor.

The valve cover gasket isn't hard to change. Oil on the plugs indicates a more serious problem. Smoke from the exhaust would be from rings, rich mixture, worn valve guides. It may be that the engine is overfull (that would show on the stick). Oil loss from a leaking gasket would smoke under the hood and leave oil on the engine and the ground.

For an engine to run, you need three things to happen inside the engine, compression, fuel and ignition, without any one of these components the engine will not run.

• Compression - Engine compression caused by crankshaft rotation and pistons moving up and down inside the engine block. If the timing belt or timing chain fails it will cause the camshaft to become out of correlation with the crankshaft or allow the camshaft to stop rotating. Either of these conditions will cause the engine to lose compression and sometimes cause internal engine damage.
  
• Fuel Delivery System - The fuel system includes: fuel pump, fuel injectors, pressure regulator, fuel filter and pressure lines. This system is used to supply fuel under pressure to the fuel injection system, the lack of fuel pressure or volume will cause the fuel delivery system to fail and the engine to stall or not start.
  
• Ignition Spark Delivery System - The ignition system components include: spark plugs, spark plug wires, distributor (if applicable), crankshaft angle sensor, camshaft angle sensor, ignition coil, ignition module, knock sensor and ECM (engine control module). The engine relies on the ignition spark to be delivered to the combustion camber at the correct time. If the ignition spark stops or is delivered at the wrong time the engine will not run or run poorly.
  

If Your Engine Cranks but Does Not Start Follow this Troubleshooting Guide
Most vehicles operate by the same principle; basic troubleshooting procedures apply to most cars.

• Step 1: Anytime you have a problem with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) inspect all fuses using a test light and check the under hood power distribution center and under dash fuse panels. If all fuses test ok continue to the next step.
  
• Step 2: To check for problems with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) and the fuses test ok a trouble code scan is needed to identify any system trouble. Use a simple scanner tool to retrieve trouble codes and see if they relate to the specific problem, like a crank angle sensor failure code. If the trouble code present does not pertain to the immediate problem like an EVAP code ignore it until a later time, after the car is running. The reason we repair non-related codes after the engine is running is because sometime false codes can be triggered by the engine not running. Once the engine is running again the code present might cycle and turn itself off. You might say "if the engine doesn't run shouldn't it have a trouble code?" Sometimes conditions occur that will not be detected by the computer, example: if the fuel pump fails the computer cannot detect the failure, so the engine doesn't start and the computer thinks everything is ok with no codes. If no trouble codes are present proceed to the next step.
  

Scan for Trouble Codes

• Step 3: The spark plugs in your engine are used to ignite the compressed fuel air mixture. If the condition of the spark plugs are fouled by excessive fuel or carbon the engine will not start, backfire or run rough. Remove all spark plugs to inspect their condition. Please use this spark plug condition reference guide to see how the spark plugs are operating.
  
• Step 4: Determine if the engine has compression, this can be done a number of ways but the most complete method is to perform a compression check. Remove the spark plugs and perform a compression test on one cylinder. If one cylinder has compression then the remaining cylinders usually will be close to the same. Crank the engine over about 5 seconds, normal compression readings should be between 125 psi and 160 psi on each cylinder. If no or little compression exists additional tests will be needed. The most common reason for an engine to lose compression is a timing belt or timing chain failure. If low or no compression exists remove the oil fill cap and observe camshaft rotation when the engine is cranked over. If no rotation exists the timing belt or chain has failed. If your engine has a timing belt and you cannot see the camshaft easily remove the upper bolts to the timing cover and gain visual access to the belt, recheck cam rotation by cranking the engine over. Sometimes a timing belt or chain can jump causing the camshaft to lose correlation with the crankshaft and therefore causing low compression. The best test for this condition is to remove the timing belt/chain cover and inspect timing marks. If the compression is ok proceed to next step.
  
• Step 5: Test the ignition system output, ignition systems can vary in configuration but operate on the same principal. Ignition systems can consist of a coil, pick up coil, crank angle sensor, cam angle sensor, spark plugs, spark plug wires, distributor cap, ignition rotor and a distributor and any variations of these components. An ignition coil is a voltage stepper coil that transforms a low voltage (12 volts) signal into tens of thousands of volts needed to jump the gap of the spark plug. This coil is activated by an ignition module triggered by using the camshaft/crankshaft angle sensor; timing is adjusted by the ECM (computer).
  This primary electrical signal is generated by the ECM which calculates spark timing by using a variety of sensors including coolant temperature, mass air flow, and oxygen sensors. To perform a basic ignition output test you must have a test light and follow this ignition system output test video.
  
  Distributor less Ignition System Configuration
  Some ignition systems have a coil for each spark plug. This is called Direct Ignition (DI) system; there are no plug wires in this system just individually controlled ignition coils. The amount of coils or spark plugs depend on the number of cylinders the engine is designed with, example: four cylinders, six cylinders etc. To perform a basic ignition output test you must have a test light follow this ignition system output test video and substitute the ignition coil for the plug wire (Note: leave the coil trigger wires connected).
  
  Coil Over Spark Plug
  If the ignition system test is weak or non-existent test the car fuses, both under hood power distribution center and the fuse panel under dash. This test is performed with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced. If the fuses are ok a manufacturer specific repair procedure is required and an online auto repair manual is needed to continue. If the ignition system tests ok proceed to the next step.
  

Test Ignition System Video

If you've got spark and fuel, it should fire up. Crank the engine for about 20 to 30 seconds then immediately pull one spark plug. if your getting fuel, it should be wet with gasoline. No wet,no gas. But then again, the code says rich mixture. Doesn't add up. Check all the connections at the mass airflow sensor and the crankshaft and camshaft sensors.

For an engine to run, you need three things to happen inside the engine, compression, fuel and ignition, without any one of these components the engine will not run.

• Compression - Engine compression caused by crankshaft rotation and pistons moving up and down inside the engine block. If the timing belt or timing chain fails it will cause the camshaft to become out of correlation with the crankshaft or allow the camshaft to stop rotating. Either of these conditions will cause the engine to lose compression and sometimes cause internal engine damage.
  
• Fuel Delivery System - The fuel system includes: fuel pump, fuel injectors, pressure regulator, fuel filter and pressure lines. This system is used to supply fuel under pressure to the fuel injection system, the lack of fuel pressure or volume will cause the fuel delivery system to fail and the engine to stall or not start.
  
• Ignition Spark Delivery System - The ignition system components include: spark plugs, spark plug wires, distributor (if applicable), crankshaft angle sensor, camshaft angle sensor, ignition coil, ignition module, knock sensor and ECM (engine control module). The engine relies on the ignition spark to be delivered to the combustion camber at the correct time. If the ignition spark stops or is delivered at the wrong time the engine will not run or run poorly.
  

If Your Engine Cranks but Does Not Start Follow this Troubleshooting Guide
Most vehicles operate by the same principle; basic troubleshooting procedures apply to most cars.

• Step 1: Anytime you have a problem with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) inspect all fuses using a test light and check the under hood power distribution center and under dash fuse panels. If all fuses test ok continue to the next step.
  
• Step 2: To check for problems with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag ) and the fuses test ok a trouble code scan is needed to identify any system trouble. Use a simple scanner tool to retrieve trouble codes and see if they relate to the specific problem, like a crank angle sensor failure code. If the trouble code present does not pertain to the immediate problem like an EVAP code ignore it until a later time, after the car is running. The reason we repair non-related codes after the engine is running is because sometime false codes can be triggered by the engine not running. Once the engine is running again the code present might cycle and turn itself off. You might say "if the engine doesn't run shouldn't it have a trouble code?" Sometimes conditions occur that will not be detected by the computer, example: if the fuel pump fails the computer cannot detect the failure, so the engine doesn't start and the computer thinks everything is ok with no codes. If no trouble codes are present proceed to the next step.
  
• Step 3: The spark plugs in your engine are used to ignite the compressed fuel air mixture. If the condition of the spark plugs are fouled by excessive fuel or carbon the engine will not start, backfire or run rough. Remove all spark plugs to inspect their condition. Please use this spark plug condition reference guide to see how the spark plugs are operating.
  

Free Auto Repair Advice by Professional Mechanics




Troubleshooting / Car Engine Cranks but Will Not Start / Engine Crank But Wont Start 2

* Why does my engine stall at idle?
* How do I change my spark plugs?
* Why does my engine stall?
* Why does the engine stall after replacing the battery?
* Why won't my engine crank over?
* How to retrieve trouble codes
* How to test fuel delivery system
* Engine cranks excessively
* Engine has excessive smoke
* Rapid ticking sounds when engine is cranked
* How to tune up your engine
* How to jump start your engine
* How to test an oxygen sensor
* How to open a car hood
* How a flywheel - flex plate works

Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine, compression, fuel and ignition, without any one of these components the engine will not run. Follow the repair guide below:


Engine Configuration with Camshaft Operation

*

Compression - Engine compression caused by crankshaft rotation and pistons moving up and down inside the engine block. If the timing belt or timing chain fails it will cause the camshaft to become out of correlation with the crankshaft or allow the camshaft to stop rotating. Either of these conditions will cause the engine to lose compression and sometimes cause internal engine damage.
*

Fuel Delivery System - The fuel system includes: fuel pump, fuel injectors, pressure regulator, fuel filter and pressure lines. This system is used to supply fuel under pressure to the fuel injection system, the lack of fuel pressure or volume will cause the fuel delivery system to fail and the engine to stall or not start.
*

Ignition Spark Delivery System - The ignition system components include: spark plugs, spark plug wires, distributor (if applicable), crankshaft angle sensor, camshaft angle sensor, ignition coil, ignition module, knock sensor and PCM (engine control module). The engine relies on the ignition spark to be delivered to the combustion camber at the correct time. If the ignition spark stops or is delivered at the wrong time the engine will not run or run poorly.

If your engine cranks but does not start follow this troubleshooting guide:
* Step 1 - Anytime you have a problem with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) inspect all fuses using a test light and check the under hood power distribution center and under dash fuse panels. If all fuses test ok continue to the next step.
* Step 2 - To check for problems with electronically controlled components such as an engine, transmission, ABS brake, or SRS (supplemental restraint system, Air Bag) and the fuses test ok a trouble code scan is needed to identify any system trouble. Use a simple scanner tool to retrieve trouble codes and see if they relate to the specific problem, like a crank angle sensor failure code. If the trouble code present does not pertain to the immediate problem like an EVAP code ignore it until a later time, after the car is running. The reason we repair non-related codes after the engine is running is because sometime false codes can be triggered by the engine not running. Once the engine is running again the code present might cycle and turn itself off. You might say "if the engine doesn't run shouldn't it have a trouble code?" Sometimes conditions occur that will not be detected by the computer, example: if the fuel pump fails the computer cannot detect the failure, so the engine doesn't start and the computer thinks everything is ok with no codes. If no trouble codes are present proceed to the next step.
* Step 3 - The spark plugs in your engine are used to ignite the compressed fuel air mixture. If the condition of the spark plugs are fouled by excessive fuel or carbon the engine will not start, backfire or run rough. Remove all spark plugs to inspect their condition. Please use this spark plug condition reference guide to see how the spark plugs are operating.
* Step 4 - Determine if the engine has compression, this can be done a number of ways but the most complete method is to perform a compression check. Remove the spark plugs and perform a compression test on one cylinder. If one cylinder has compression then the remaining cylinders usually will be close to the same. Crank the engine over about 5 seconds, normal compression readings should be between 125 psi and 160 psi on each cylinder. If no or little compression exists additional tests will be needed. The most common reason for an engine to lose compression is a timing belt or timing chain failure. If low or no compression exists remove the oil fill cap and observe camshaft rotation when the engine is cranked over. If no rotation exists the timing belt or chain has failed. If your engine has a timing belt and you cannot see the camshaft easily remove the upper bolts to the timing cover and gain visual access to the belt, recheck cam rotation by cranking the engine over. Sometimes a timing belt or chain can jump causing the camshaft to lose correlation with the crankshaft and therefore causing low compression. The best test for this condition is to remove the timing belt/chain cover and inspect timing marks. If the compression is ok proceed to next step.
* Step 5 - Test the ignition system output, ignition systems can vary in configuration but operate on the same principal. Ignition systems can consist of a coil, pick up coil, crank angle sensor, cam angle sensor, spark plugs, spark plug wires, distributor cap, ignition rotor and a distributor and any variations of these components. An ignition coil is a voltage stepper coil that transforms a low voltage (12 volts) signal into tens of thousands of volts needed to jump the gap of the spark plug. This coil is activated by an ignition module triggered by using the camshaft/crankshaft angle sensor; timing is adjusted by the ECM (computer).

Hope helps (remember rated and comment this).

Many new cars hide most of the engine underneath plastic covers that must be removed to find anything. The smoking problem may or may not be serious, but it's likely that the spark plugs will show black oily deposits on the interior insulators. Cleaning or replacing the plugs will usually make the engine run ok for awhile, but with continued smoking, it will foul the plugs again. If all the plugs are fouled, then look for something like a bad PCV valve that creates crankcase pressure when plugged. Worn out valve seals which allow oil to leak into the cylinders can account for smoking only on start-up. These seals can usually be replaced without pulling the cylinder head. Hope this helps!

check your ground wires. its quite common that they rust off and then that causes a no start. check along the frame by the battery, and starter.