Engine repair tasks A1-A9

D. thinking of possible causes should come after customer is input. the customer should finish completely before questioning begins. a road test should be performed after the customer is heard

63. The first step a technician should take toward determining the cause of a problem is: A. think of possible causes of the problem. B. question the customer. C. road test the vehicle. D. listen to the customer.

C. The customer should be questioned, if possible. the customer complaint should always be eliminated. a road test should always be performed to verify the repair.

92. The LEAST likely step in a diagnostic procedure would be to: A. question the customer for more information regarding the problem. B. be sure that the customer complaint is eliminated. C. start with the most difficult test. D. road test the vehicle.

D. disabling the faulty cylinder will cause engine rpm to drop less than for the other cylinders. disabling the faulty cylinder will not cause the engine to stall.

A cylinder balance test is being performed on an engine to determine which cylinder is a "miss." Technician A says that when the faulty cylinder is disabled, engine rpm will drop more than for the other cylinders. technician B says disabling the faulty cylinder will cause the engine to stall. who is right? A. A only B. b only C. Both A and B D Neither A nor B

C. [A faulty ignition system is likely to cause a weak cylinder.] [A burned exhaust valve is likely to cause a weak cylinder.] [A leaking intake manifold is likely to cause a weak cylinder.]

A cylinder balance test on carbureted engine has revealed one cylinder that is contributing much less power than the other cylinders. The LEAST likely cause of this problem is: A. a faulty ignition system B. a burned valve C. a faulty carburetor D. a leaking intake manifold

B. worn pistons and cylinders would cause thumping noise during acceleration. worn main bearings would cause a thump when the engine is started. loose camshaft bearings would cause a thumping noise at all times

A heavy thumping noise occurs with the engine idling, but the oil pressure is normal. This noise may be caused by: A. worn pistons and cylinders B. loose flywheel bolts C. worn mean bearings D. loose camshaft bearings

D. An intake manifold leak causes a pitched whistle at idle and low speeds. A choke stuck closed will not cause a high pitched whistle. A feul system leak would not cause a noise.

A high pitched squealing noise is heard during hard acceleration. This noise may be caused by: A. an intake manifold leak B. the choke stuck closed C. a fuel system leak D. a small leak in the exhaust manifold

B. burned or leaking valves cause a fluctuation between 12 and 18 in. hg. weak valve springs cause a fluctuation between 10 and 25 in. hg. a leaking head gasket would cause a fluctuation between 7 and 20 in. hg.

A low, steady vacuum gauge reading as shown above indicates: A. burned or leaking valves B. a late ignition timing C. weak valve springs D. a leaking head gasket

B. a florescent, strobe, or infrared light will not cause the dye to glow

A technician has added fluorescent dye to an engine crankcase in order to locate an oil leak. the dye will glow when it is exposed to: A. A fluorescent light B. an ultraviolet light C. a strobe light D. an infrared light

D. low oil pressure, level, or worn lifter bottom would result in a continuous noise.

After a vehicle is parked overnight and then started in the morning, the engine has a lifter noise that disappears after running a short while. The most likely cause would be: A. low pressure B. low oil level C. a worn lifter bottom D. excessive lifter leak-down

B. A loose timing chain would not affect just two cylinders.

After performing a compression test on a v8 engine, two cylinders have pressure readings of 60 psi while the others have a reading of 135 psi. The two low cylinders are next to each other. Technician A says this could be caused by a loose timing chain. Technician B says a leaking head gasket could cause this. Who is right? A. A only B. B only C. Both A and B D. Neither A nor B

A. if cylinder leakage exceeds 20 percent, check for air escaping from the tailpipe, the positive crankcase ventilation PCV valve opening in the rocker arm cover, and the top of the throttle body or carburetor. air leaking from the tailpipe most likely indicates an exhaust valve leak.

An engine is being diagnosed using a cylinder leakage test. Technician A says that any cylinder with over 20 percent leakage has excessive leakage. Technician B says that air leaking from the tailpipe indicates a cracked cylinder head. who is correct? A. A only B. B only C. Both A and B D. Neither A nor B

D. Retarded timing would not result in gauge fluctuation. Advanced timing would not result in gauge fluctuation. A stuck EGR valve would not result in gauge fluctuation.

An engine is idling at 750 rpm. A vacuum test is performed The pointer on the vacuum gauge is floating between 11 and 16 in. Hg. The most likely cause would be: A. retarded timing B. advanced timing C. a stuck EGR valve D. too lean an idle mixture

C. A lean fuel mixture would not cause a sulfur smell. coolant leaking into the exhaust chambers would cause a gray exhaust color. a vacuum leak would cause a rough idle that would decrease as engine speed increases.

An excessive sulfur smell in the exhaust of a vehicle with a catalytic converter can be an indication of: A. a lean fuel mixture B. coolant leaking into a combustion chamber C. a rich fuel mixture D. a vacuum leak

A. [If there is an increase in pressure during a wet compression test, this indicates worn piston rings] [if an exhaust valve is burned, compression would not increase during a wet test.] [if an engine had a worn camshaft lobe, compression would not increase during a wet test.]

During a compression test, a cylinder has 40 percent of the specified compression reading. When the technician performs a wet test, the compression reading on this cylinder has 75 percent of the specified reading, The cause of the low compression reading could be: A. worn piston rings B. a burned exhaust valve C. a bent intake valve D. a worn camshaft lobe

C. both a misfiring ignition system and an intake manifold leak could cause a cylinder to contribute too little power.

During a cylinder balance test on an engine with electronic fuel injection, one cylinder provides very little rpm drop. technician A says the ignition system may be misfiring on that cylinder. Technician B says the engine may have an intake manifold vacuum leak who is right? A. A only B. B only C. Both A and B D. Neither A nor B

D. worn intake valves would cause air leaks at the throttle body or carburetor. worn exhaust valves would cause air to leak at the tailpipe. a broken PCV valve would not cause air to leak.

During a cylinder leakage test, air comes out the pcv valve opening in the rocker arm cover. this is an indication of: A. worn intake valves B. worn exhaust valves C. a broken PCV valve D. worn piston rings

D. three drops every 100 feet would result in the loss of 3 quarts every 1,000 miles.

Even a small oil leak can result in major oil loss. On a particular car it has been estimated that three drops of oil leaking every 100 feet results in a total of 3 quarts of oil loss every: A. 100 miles B. 500 miles C. 1,500 miles D. 1,000 miles

A. removing spark plugs is not the first step that should be taken. the ignition system should be disabled before the engine is rotated by hand. the spark plugs must be removed before you can watch for coolant or oil flow from the spark plug holes

If the starter motor does not crank the engine, the first diagnostic step that the technician should perform is to: A. disable the ignition system. B. remove the spark plugs. C. rotate the engine by hand. D. watch for oil or coolant flow from the spark plugs.

C. Both stuck piston rings and a plugged oil drain passage in the cylinder head may allow excessive oil to enter the cylinders. this oil would produce blue/gray smoke when it burned.

Technician A says blue-gray smoke coming from the exhaust may be caused by stuck piston rings. Technician B says this could be caused by a plugged oil drain passage in the cylinder head. who is right? A. A only B. B only C. Both A and B D. Neither A nor B

A. if engine is cranking properly, the battery would have sufficient voltage. compression would not be the first test to perform. because engine vacuum is low during cranking, a vacuum test would not be conclusive.

The customer complains that the engine cranks but does not start; the first thing to check should be: A. valve train operation. B. battery voltage. C. compression. D. engine vacuum.

A. a cracked cylinder block would be unlikely to cause a hard start condition.

The customer says that the engine requires excessive cranking to start. The LEAST likely cause of this problem would be: A. a cracked cylinder block. B. a jumped timing belt. C. a faulty fuel pump. D. a stuck-open valve.

D. [A low reading on two adjacent cylinders may indicate a blown head gasket or a cracked cylinder head.] [carbon buildup would cause a high reading.]

When using a compression tester, the compression readings on the cylinders are all even, but lower than the specified compression. This could indicate: A. a blown head gasket B. carbon buildup C. a cracked head D. worn rings and cylinders

D. loose pistons may cause a rapping noise while accelerating. worn cylinders may cause a rapping noise while accelerating. worn main bearing may cause a thumping sound when starting

Which of the following is LEAST likely to cause engine noise? A. loose pistons B. Worn cylinders C. Worn main bearings D. Loose camshaft bearings

B. The easier diagnostic procedures should be performed before attempting more difficult procedures.

While discussing basic diagnostic procedure, technician A says the most complicated diagnostic test should be performed first. Technician B says that you should first question the customer to obtain as much information as possible about the problem. Who is right? A. A only B. B only C. Both A and B D. Neither A nor B

D. late ignition timing would result in a low, steady reading. intake manifold leaks would cause a very low, steady leak. a restricted exhaust system would cause vacuum to slowly decreases after the engine was accelerated and held steady.

With the engine idling, a vacuum gauge connected to the intake manifold fluctuates between 16 and 20. these vacuum gauge fluctuation may be caused by: A. late ignition timing B. intake manifold vacuum leaks C. a restricted exhaust system D. sticky valve stems and guides

A a leaking exhaust valve would cause air to leak from the tailpipe. A leaking head gasket or a cracked would cause air to leak from the radiator filler neck. worn piston rings would cause air to leak from the opening in the rocker arm cover

during a cylinder leakage test using a cylinder leakage test, as shown in the figure, the reading on the leakage tester exceeds 20 percent. The LEAST likely place that the technician would check for leaking air would be from the: A. tool air hose B. Vehicle tailpipe C. radiator filler neck D. pcv valve opening in the rocker arm cover

C. oil leaking from the crankshaft rear main bearing seal could e caused by a faulty seal or a malfunctioning PCV system.

oil is leaking from the crankshaft rear main bearing seal on an engine. Technician A says the oil seal could be faulty. Technician B says the PCV system may not be functioning. who is right? A. A only B. B only C. Both A and B D. Neither A nor B