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Engine diagnosis and causes for spark plugs carbon deposits

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Anonymous

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Posted on Aug 12, 2011

Anonymous

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Common causes of carbon deposit in spark plug:

1. blown head gasket.
2. faulty piston ring.
3. cracks/leaks in the cylinder head. this is quite serious.

possible solutions for number 3 are:
1. resurfacing of cylinder head
2. reboring of combustion chamber
3. resleeving/replacing of pistons.

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1answer

I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

Could be the engine, until the overhaul, was run on a low grade or low specification oil that allowed or even encouraged sludge and carbon to build up in the engine.
If a high detergent oil was used at the overhaul it would have scoured the inside of the engine, removing deposits so increased oil consumption is often the result.

The additive packs of some oils also tend to cause the premature hardening and failure of some types of rubber seal, though this was a huge problem 20-30 years ago it isn't seen much today.

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May 13, 2019 • Honda Cars & Trucks

tip

Engine Diagnosis Old Spark Plug Condition

Old spark plugs removed from your engine can tell a lot about the condition of the engine. Experienced mechanics can use this information to help diagnose several conditions simply by examining the state of the old plugs.

This tip is written as a useful guide to help diagnose engine problems and give a general indicator of the state of your engine. If you have ever wondered what you can tell from the condition of your old spark plugs please see the illustrations below.

As an example note that conditions such as over advanced ignition timing, lean fuel mixture or intake manifold leaks can often be determined from a plug that shows absence of deposits and a burnt or eroded electrode. However, sometimes this condition is caused by incorrect spark plugs having been fitted at some stage and in this case can be easily rectified by replacing the spark plugs with plugs that are in the correct heat range.

More serious conditions can be determined from oily deposits which indicate that oil is leaking past the valves guides or piston rings. In this case the mechanical fault will need to be rectified which will involve an engine strip down. These symptoms when seen on old spark plugs are a very significant diagnostic pointer as to how the engine has been performing up to this point and can help identify faults in the engine itself

The first picture in the illustration is of a healthy spark plug. Please follow through each of the images and you can compare your old spark plug against each of the images for a description of the engine problems that are associated with it.

Thanks for viewing my Tip.

Normal: Here we see a normal used plug which should be a brown to greyish color with only slight electrode wear. This plug has been operating correctly and is the in correct heat range for the vehicle.

Worn: On this plug you can see a rounded electrode. The normal colour deposits are seen but this plug has simply been in the vehicle too long.

Plug Run Too Hot. The symptoms here are a blistered white insulator with an eroded electrode and an absence of deposits.
Causes: Incorrect heat range plug used, over advanced ignition timing, lean fuel mixture, intake manifold vaccuum leak, sticking valves or insufficient engine cooling.

Carbon Deposits: Dry sooty deposits like this indicate either a rich fuel mixture or a weak ignition. This is a good indicator of a clogged air filter or a problem in the fuel or engine management system. Also check for ignition problems.

Preignition: Here we see melted electrodes. You will note the insulator is white. This is an indication of severe misfiring and overheating. Can be an indicator of severe engine damage. Causes: Check for over advanced ignition timing, lean fuel mixture, insufficient engine cooling and lack of lubrication in the engine. Also check correct heat range plug has been used.

Ash Deposits: Encrusting of light brown deposits observed on the electrodes. Causes: Oil or fuel additives - try changing the gas brand that you are using. Severe cases often indicate engine valve seal problems whereby oil is seeping into the combustion chambers.

High Speed Glazing: Insulator looks glazed and yellow. Condition is associated with sudden temperature rises from hard accelleration of the engine. Plugs in this condition can cause misfires at high speeds. These plugs will need to be changed and consider replacement with a colder temperature range plug.

Oil Deposits: Indicative of oil leaking past the valve guides or piston rings and fouling the plug. Vehicle will run badly. Engine will need stripdown and repair.

Detonation: Insulator appears cracked or chipped. May have resulted from poor gapping technique which has damaged insulator. Can lead to piston damage. Replace plugs and ensure fuel anti knock values are correct. Ensure plugs are carefully and correctly gapped.

Gap Bridging: In this case deposits can clearly be seen lodged between the electrodes. The plug will not fire and this results in a dead cylinder. Clean or replace the plug.

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on Dec 12, 2009 • Toyota Corolla Cars & Trucks

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Can a knock sensor cause knock in a 95 4.3 vortec

The knock sensor simply looks for the symptoms of 'knocking'. Knocking is caused when the fuel/air mixture ignites at the wrong time in the four stroke cycle. (Too early or too late). The 3 most common reasons are...
a: The wrong standard or 'octane' of fuel is being used.
b: The wrong type of sparkplug is fitted.
c: The inside of the cylinder is coated in carbon, (soot), deposits.
Should you be using super unleaded or standard unleaded? Check which one is correct for that engine.
Check the spark plugs are the ones designed for that engine. Some can be slightly longer or shorter affecting where the spark ignites the fuel mix.
If the engine cylinder is coated in carbon the cylinder head will have to be removed and professionally cleaned.

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Jan 12, 2019 • Chevrolet Cars & Trucks

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1answer

My 2003 pontiac aztek shuts off when its in idle

Could have a vacuum leak , a problem with the IAC - idle air control motor !
Rough, Unstable, or Incorrect Idle and Stalling
Inspection/Test
Action
DEFINITION: Engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.
Preliminary
?€¢
Refer to Diagnostic System Check - Engine Controls .

?€¢
Refer to Intermittent Conditions before starting.

?€¢
Search for bulletins.

?€¢
Observe the owners driving habits.

Fuel System
?€¢
Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .

?€¢
Test for low fuel pressure. Refer to Fuel System Diagnosis .

?€¢
Test for faulty fuel injectors. Refer to Fuel Injector Balance Test with Special Tool , Fuel Injector Balance Test with Tech 2 , Fuel Injector Solenoid Coil Test test procedures.

?€¢
Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

?€¢
Inspect for fuel in the pressure regulator vacuum hose.

?€¢
Ensure each injector harness is connected to the correct injector/cylinder.

?€¢
Inspect for any items which may cause an engine to run rich, long term fuel trim is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 .

?€¢
Inspect for any items which may cause an engine to run lean, long term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Sensor/System
?€¢
Test for conditions which cause an incorrect idle speed.

-
Throttle body tampering, excessive deposits, or damage--Refer to Fuel System Description .

-
Restricted air intake system

-
Large vacuum leak

?€¢
Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.

?€¢
Inspect crankcase ventilation valve for proper operation.

?€¢
Inspect the throttle position (TP) sensor and related wiring. Refer to DTC P0123 .

?€¢
Monitor the 24X crank sensor and the CMP sensor signal present parameters on the scan tool. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor A and CMP sensor circuits for intermittents. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

?€¢
Monitor the 3X parameter on the scan tool. If the 3X is not responding, inspect the CKP sensor B and circuits for intermittents. Inspect the ignition control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open, or shorted, they may not set a diagnostic trouble code (DTC) immediately, but are capable of causing driveability complaints. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

?€¢
Test the exhaust gas recirculation (EGR) system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

?€¢
Inspect the Transaxle Range Switch input with the vehicle in drive and the gear selector in drive or overdrive

Ignition System
?€¢
Inspect for proper ignition voltage output using the following steps:

1.
Attach the J 26792 Spark Tester to engine ground.

2.
Connect the spark plug end of the spark plug wire to the J 26792 . Leave the other end of the spark plug wire connected to the coil being tested.

3.
Connect the spark plug end of the companion spark plug wire to ground. The companion spark plug wire is the wire attached to the corresponding coil tower.

4.
Crank the engine while observing the J 26792 . A spark should be observed.

5.
Repeat the above steps for each coil.

?€¢
If spark is not present at the coils, inspect for the following conditions:

-
Coils--Cracks, carbon tracking/arcing, or a resistance value outside the specified range

Coil Resistance
5000-8000 ohms (5K-8K ohms)
-
Spark plug wires--Signs of arcing, cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range

Spark Plug Wire Resistance
9 686 ohms per meter (3,000 ohms per foot)
Important: : Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.

-
Defective ignition module

-
Ignition system wiring--Loose ignition module feed or ground connection, or damaged system wiring

?€¢
Remove spark plugs and inspect for the following conditions:

-
Fouled plugs

-
Cracks

-
Wear

-
Improper gap

-
Burned or damaged electrodes

-
Improper heat range or reach

?€¢
If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs. Refer to Spark Plug Inspection .

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Sep 27, 2015 • Pontiac Cars & Trucks

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Hard starting

This problem can be hard to track down , it could be caused by several thing's ! A bad check valve in the fuel pump letting fuel drain back into the tank , not keeping fuel line pressure up , a crankshaft position sensor can also cause this as well as an ignition control module !
Checks
Action
DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.
Preliminary
?€¢
Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .

?€¢
Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations. Refer to Engine Controls Schematics .

?€¢
Search for bulletins.

Sensor/System
?€¢
Test the engine coolant temperature (ECT) sensor for being shifted in value. Connect a scan tool. Compare the engine coolant temperature against the intake air temperature (IAT) on a cold engine. The ECT and IAT sensor values should be within ?± 3?°C (5?°F) of each other. If the ECT sensor is out of range with the IAT sensor, check the resistance of the ECT sensor. Refer to Temperature Versus Resistance for resistance specifications. Replace the ECT sensor if the resistance is not within the specification. If the sensor is within the specification, repair the ECT signal circuit for high resistance.

?€¢
Inspect the mass air flow (MAF) sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Important: The embossed arrows on the MAF sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Install the MAF in the proper direction. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .

?€¢
Inspect the camshaft position (CMP) sensor for proper mounting and/or a bad connection. A long crank time occurs if the PCM does not receive a CMP signal.

Fuel System
?€¢
Inspect the fuel pump relay operation. The fuel pump should turn ON for 2 seconds when you turn ON the ignition. Refer to Fuel Pump Electrical Circuit Diagnosis .

?€¢
A faulty in-tank fuel pump check valve allows the fuel in the lines to drain back to the tank after the engine stops. Refer to Fuel System Diagnosis .

?€¢
Inspect both injector fuses for being open. An open injector fuse causes four injectors and four ignition coils not to operate. Replace the fuse. Inspect the injector circuits and the ignition coil circuits for an intermittent short to ground.

?€¢
Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis .

?€¢
Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis .

?€¢
Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
?€¢
Test both injector fuses for being open. An open injector fuse causes four ignition coils and four injectors not to operate. Replace the fuse. Inspect the ignition coil circuits and the injector circuits for an intermittent short to ground.

?€¢
Inspect for proper ignition voltage output with J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis .

?€¢
Remove the spark plugs and check for the following:

-
Correct heat range

-
Wet plugs

-
Cracks

-
Wear

-
Improper gap

-
Burned electrodes

-
Heavy deposits

Refer to Spark Plug Inspection in Engine Electrical.
?€¢
Determine the cause of the fouling before replacing the spark plugs if the spark plugs are gas, coolant, or oil fouled. Refer to DTC P0172 or P0175 for diagnosis of the rich condition. Refer to Spark Plug Inspection in Engine Electrical for diagnosis of coolant or oil fouled spark plugs.

?€¢
Inspect for bare or shorted ignition wires.

?€¢
Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis .

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Jul 14, 2015 • 2002 GMC Sierra 1500

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02 mitsubishi lancer oz rally automatic and when I turned it off the engine sputtered a little so I turned it back on started up back fine and shut it off and it sputter again Its neverdone thisHelp?

I think what you are describing may be "run on" or Dieseling" which is a way of saying that an ngine with spark plugs that should stop when the key is turned off, continues to run in a rough manner. This is typically caused by glowing carbon in the cylinder, often on the head next to a fouled spark plug tip.
I would recommend changing the spark plugs and spending the $ for some "tune up in a can" that removes carbon deposits from inside the cylinders.
Hope this helps.

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Apr 04, 2015 • 2002 Mitsubishi Lancer OZ Rally

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1answer

Engine does not shut off when u turn ignition off unless you kick it in reverse

Does it run rough and rattle? If so, carbon deposits are causing engine to "deisel" or "run on". This is also caused by incorrect ignition timing or bad spark plugs.

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Feb 23, 2015 • Cars & Trucks

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Car doesnt idle normal after engine gets warm

could be dirty or defective spark plugs! remove spark plugs (engine cold) and try cleaning using a motor cleaner and remove those carbon deposits at the tip. also examine tips for corrosion. if the tips are worn out, time to replace those plugs. the manual recommends to replace spark plugs every 10,000 kilometers.

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May 05, 2011 • Toyota Corolla Cars & Trucks

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1answer

When do the spark plugs need changed

Spark plugs like any electrical device become worn over time. Spark plugs also work under extreme condition. The use of cheap fuels will leave deposits, poor maintenance, bad air filters, old plug wires, all these items can cause a spark plug to fail or not perform at its peak level. Also spark plugs use a gap or Electrical bridge that is used for high voltage to arc across. The larger the gap the hotter the spark until you reach a point that the coil can not bridge the gap and then you get a misfire. Also when a plug gets deposits from either oil, poor fuel, carbon this will shorten the gap and cause a weaker spark resulting in poor performance, wasted fuel and engine dieseling or Run on after the ignition is turned off.
These are the simple reasons for spark plug replacement.

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Jul 19, 2010 • 2005 Dodge Caravan

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1999 ford tauruscan you tell by looking at spark plugs if you have a head gasket leak? car is missing and sputteringit's not blowing smoke.wondering what the plugs should look like with 35'000 miles on...

mcdevito75 here, Even a tiny crack in a cylinder head gasket would cause 2 spark plugs, one right next to each other to missfire, those plugs would have a whiteish color, (2 plugs next to each other) also, a head gasket would naturally cause a loss of antifreeze as it is leaking and burning in the engine. Normal plugs have a redish brown tint, but may also be a bit dark from carbon deposits.

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Jul 07, 2010 • 1999 Ford Taurus

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I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

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Engine diagnosis and causes for spark plugs carbon deposits

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Anonymous

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Related Questions:

I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

Engine Diagnosis Old Spark Plug Condition

Can a knock sensor cause knock in a 95 4.3 vortec

My 2003 pontiac aztek shuts off when its in idle

Hard starting

02 mitsubishi lancer oz rally automatic and when I turned it off the engine sputtered a little so I turned it back on started up back fine and shut it off and it sputter again Its neverdone thisHelp?

Engine does not shut off when u turn ignition off unless you kick it in reverse

Car doesnt idle normal after engine gets warm

When do the spark plugs need changed

1999 ford tauruscan you tell by looking at spark plugs if you have a head gasket leak? car is missing and sputteringit's not blowing smoke.wondering what the plugs should look like with 35'000 miles on...

Not finding what you are looking for?

Cars & Trucks

I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

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Trustworthy Expert Solutions

Engine diagnosis and causes for spark plugs carbon deposits

1 Answer

Anonymous

Add Your Answer

Attachments: Added items

Related Questions:

I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

Engine Diagnosis Old Spark Plug Condition

Can a knock sensor cause knock in a 95 4.3 vortec

My 2003 pontiac aztek shuts off when its in idle

Hard starting

02 mitsubishi lancer oz rally automatic and when I turned it off the engine sputtered a little so I turned it back on started up back fine and shut it off and it sputter again Its neverdone thisHelp?

Engine does not shut off when u turn ignition off unless you kick it in reverse

Car doesnt idle normal after engine gets warm

When do the spark plugs need changed

1999 ford tauruscan you tell by looking at spark plugs if you have a head gasket leak? car is missing and sputteringit's not blowing smoke.wondering what the plugs should look like with 35'000 miles on...

Not finding what you are looking for?

Cars & Trucks

I have honda generator,overhauled last year,last week i changed oil from then onward oil level is getting low but not that low . with white smoke at the start of generator and oil burning smell.

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