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Makes knocking noise every - MPV Mazda Cars & Trucks

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This can be a serious defect. About all you can try that may be a parts swap is a "Knock sensor". Beyond that, disabling a fuel injector is something which would reduce the power stroke on a cylinder and allow you to pick out the bad cylinder from quieting the engine down. Just go from one to the other and test.
This helps with any V design engine because you can remove only the bad head and leave the good side intact. But with a inline 4 cylinder, it does not help you. And knowing the bad cylinder should not stop you from measuring all bearing clearances anyway. Disassembly is unavoidable.
Now the sound you describe is variable, one mechanics "Tap" is another Mechanics' "knock". This is important in looking for problems in the top of the engine versus the bottom of the engine.
Last, some of the better testing machines can systematically kill the spark from each cylinder electronically as the engine runs. This would eliminate trying to eliminate fuel injectors.
Finally, some designs have automatic timing advancers which could stick and be over advanced.

Posted on Apr 25, 2013

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Every what?

Posted on Apr 25, 2013

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Posted on Jan 02, 2017

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2 Answers

Does a knock sensor sound like a rod knocking


Knock Sensor contains no moving parts and can not make any noise. It only detects noise in the engine block to allow the engine control computer to make adjustments as needed.

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have the timing checked if its off it could be pre-ignition which some people describe as a knock. if its a heavy knocking noise it could be a piston noise or it may even be a bad crankshaft/connecting rod/bearing. have the oil pressure checked this may help to know what to do. some people describe a rocker noise as a knock but its more like a ticking noise at the top end in the area of the valve covers.

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Listen to the engine, if the noise is down low it is rod if it is up high it is valves. IF it is rod knock it will eventually throw the rod.

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Makes knocking noise that sound like something is loos banging only when jeep warms up and only in gear


TROUBLESHOOTING ENGINE NOISES
A KNOCKING SOUND IN THE ENGINE IS MOST LIKELY CAUSED BY ONE OF THE FOLLOWING
1. PISTON SLAP: Makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
2. VALVE NOISE: Makes clicking or rattle noise. Caused by excessive wear on valve stem or lifter, out of adjustment, or stuck valve. Correct by adjusting valve clearance, replace worn valve or lifter, regrind cam, replace valve guide and /or valve. A stuck valve can sometimes be loosened by passing oil through the carburetor while engine is running.

3. ROD BEARING KNOCK: Makes sharp metallic noise similar to a piston slap. Detection is opposite of piston slap. Rod knock is not heard at idle. Knock becomes louder as engine speed is increased. Caused by excessive rod bearing clearance. Correct by adjusting rod bearing clearance to .0015 inches by removing shims. May require re-pouring rod bearing.
4. REAR MAIN BEARING KNOCK: Makes dull knocking or thud noise. Detected at speeds between 20 and 50 MPH. Knock will normally decrease or disappear while pulling or decelerating. Noise will be detected the loudest at normal driving speed, when not pulling or decelerating. Correct by adjusting bearing clearance to .001 to .0015 inches. If knock is excessive, crank should be checked for out of roundness. May need to re-pour all main bearings to correct.
5. TIMING GEAR KNOCK: usually the most difficult to diagnose. If gear is loose or badly worn it will knock in all ranges. Run engine slightly above idle speed. Slowly open and close throttle. Knock will continue to be present, but just as engine slows down knock will become a slight rattle. Remove timing pin and reinsert into timing hole on timing gear cover. Press timing pin tightly against timing gear and accelerate slightly above idle. Knock will significantly be reduced or disappear. Correct by replacing both timing gear and crank gear as a matched set. The two gears should have a backlash clearance of .003 to .004. If more than .009 inch backlash, an oversize (.005) timing gear should be installed.
6. WRIST PIN SLAP: This can not be detected by shorting out the cylinder plugs. Rapidly accelerate and decelerate the engine speed. The engine will pass through a certain speed range when the wrist pin will rattle at about the same pitch as a valve tappet noise. This can be corrected by installing a new wrist pin bushing in the rod or new wrist pin f badly worn. Wrist pin should fit the piston and connecting rod with a tight metal to metal fit. The pin can be pushed into the piston and rod with a slight pressure of the hand. Pin to rod clearance is .0003 to .0005 inches.

Dec 07, 2013 | Jeep Cars & Trucks

1 Answer

Making knocking sound


A KNOCKING SOUND IN THE ENGINE IS MOST LIKELY CAUSED BY ONE OF THE FOLLOWING
1. PISTON SLAP: Makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
2. VALVE NOISE: Makes clicking or rattle noise. Caused by excessive wear on valve stem or lifter, out of adjustment, or stuck valve. Correct by adjusting valve clearance, replace worn valve or lifter, regrind cam, replace valve guide and /or valve. A stuck valve can sometimes be loosened by passing oil through the carburetor while engine is running.

3. ROD BEARING KNOCK: Makes sharp metallic noise similar to a piston slap. Detection is opposite of piston slap. Rod knock is not heard at idle. Knock becomes louder as engine speed is increased. Caused by excessive rod bearing clearance. Correct by adjusting rod bearing clearance to .0015 inches by removing shims. May require re-pouring rod bearing.
4. REAR MAIN BEARING KNOCK: Makes dull knocking or thud noise. Detected at speeds between 20 and 50 MPH. Knock will normally decrease or disappear while pulling or decelerating. Noise will be detected the loudest at normal driving speed, when not pulling or decelerating. Correct by adjusting bearing clearance to .001 to .0015 inches. If knock is excessive, crank should be checked for out of roundness. May need to re-pour all main bearings to correct.
5. TIMING GEAR KNOCK: usually the most difficult to diagnose. If gear is loose or badly worn it will knock in all ranges. Run engine slightly above idle speed. Slowly open and close throttle. Knock will continue to be present, but just as engine slows down knock will become a slight rattle. Remove timing pin and reinsert into timing hole on timing gear cover. Press timing pin tightly against timing gear and accelerate slightly above idle. Knock will significantly be reduced or disappear. Correct by replacing both timing gear and crank gear as a matched set. The two gears should have a backlash clearance of .003 to .004. If more than .009 inch backlash, an oversize (.005) timing gear should be installed.
6. WRIST PIN SLAP: This can not be detected by shorting out the cylinder plugs. Rapidly accelerate and decelerate the engine speed. The engine will pass through a certain speed range when the wrist pin will rattle at about the same pitch as a valve tappet noise. This can be corrected by installing a new wrist pin bushing in the rod or new wrist pin f badly worn. Wrist pin should fit the piston and connecting rod with a tight metal to metal fit. The pin can be pushed into the piston and rod with a slight pressure of the hand. Pin to rod clearance is .0003 to .0005 inches.

Dec 06, 2013 | Nissan Cars & Trucks

1 Answer

KNOCKING NOISE IN ENGINE UNTIL CAR WARMS UP


I have the same car, but my engine makes the knocking noise after I turn it off for about two seconds. Has this happened to anyone else? Dealership says it's normal. All this cars make this noise.

Mar 24, 2012 | Hyundai Motor 2002 Elantra

1 Answer

Not getting oil to the pistons. Making knocking noise. Wont stay on.


Hello
Has the engine been run low on oil? Does the knocking get louder as the engine warms up? Have you had a automotive technician listen to this noise? Pistons don't really knock, the bearings in the engine called the crankshaft and piston connecting rod bearings do make a loud knocking noise, if that is the case the engine must be removed from the car and rebuilt.

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2 Answers

The engine has a nkockig sound..could this be caused by a bad knock sensor?


No it isnt a knock sensor the knock sensor job is to detect a knock noise and ****** timing. The knock that it is looking for is from octane or fuel or pinging that creates N0X s. A pollution gas. The knocking noise that you are hearing is different. If it is a multiple noise ar a rattling sound that will be the valves. There are other noises like a piston knock this knock is a sharp metallic noise, If the knock occurs only on acceleration that noise is a crankshaft noise. You need to check you oil level and make sure it is corrects. Look at the oil condition do you see silverish or whitish condition,is the oil deep black.

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