Failure phenomenon: a 2009 annual Honda Odyssey car, mileage is 113,500 km. When the engine coolant temperature after the temperature reaches the normal air conditioning, sometimes abnormal sound, especially in the red light stop (brake pedal is depressed at this time, the transmission gear while hanging in the air-conditioning fan operation D) when the noise significantly.
Diagnostic Analysis: After the pick, the first observation sound I site and determines the sound volume. Test found, open air, air conditioner compressor clutch pull, when the two fans before start of operation, the engine will be heard in the right front portion ldquo; clicking, clicking rdquo; abnormal sound. Air conditioning compressor clutch does not pull no abnormal sound, and sometimes no sound.
Honda Accord Odyssey and other models are at the right front portion of the engine power steering pump, water pump, belt tension pulley, air conditioner compressor and a common crankshaft belt wheel is connected to tape drives . To confirm that the sound source is from within or outside the engine block of the engine accessory, the author first compressor removal tape, starting the car, the engine speed added to 4 500 ~ 5 000 r / min, repeated several times also amount the accelerator pedal sound came out, so I think that symptom is abnormal sound engine accessories abnormal wear and tear. Since Honda Odyssey compressor automatic tensioning belt tension pulley, the tension pulley spring if the load increases, the spring is too large will cause similar changes ldquo; clicking, clicking rdquo; sound.
After the replacement of a new attempt tension pulley assembly test fault persists. Consider again the author, if the compressor piston rod abnormal wear, will produce a sound similar to the engine knocking when the engine high load operation, and the fault will be a generation of abnormal noise of the compressor clutch pull. Just have a workshop with models of the car accident, the author will be replaced after a compressor test, abnormal sound problem still exists. I listen to parts of the abnormal sound, the feeling is still in power steering pumps, generators, water pumps, etc. and tape tension pulley. Alternatively the above components one by one test, the failure phenomena are present. Diagnose this impasse, the failure.
I go back again to consider the entire repair process diagnostics, once thought to reflect the owner: when depressing the brake pedal, the vehicle hanging in the air conditioning and the D block abnormal sound outSignificantly, it will lift the vehicle, a person depresses the brake pedal in the car hanging D fend off air conditioning, people listen to another site in the vicinity of the fault, the sound feeling crankshaft belt wheel is large. If the belt wheel crankshaft damper failure will produce large vibrations when the engine load operation, so try first crank wheel tape replacement, but the problem is not solved.
new Guangzhou Honda Odyssey, Accord and other models are driven timing chain and timing chain tensioner to rely on oil pressure automatic tensioning form. Crankshaft position sensor signal is within the crank disk tape, if the timing and crankshaft position sensor fails, it appears to be difficult to start, the vehicle can not accelerate the speed and poor fault. But the car started, driving is normal, just another car ran more than 110,000 km, the front of the accident is not yet over collision occurs, there is no engine overhaul, and normally should be no problem, but after replacing the external accessory abnormal sound the same It exists, and the noise is too large at the crank disk tape. In desperation, I tried to dismantle timing chain cover and crankshaft position sensor, and finally found the problem after the open. The original oil pump timing chain tensioner plastic rail break in the chain, causing the oil pump drive chain Songkuang, in the brake, and block D hanging open air when the engine load is large, the chain jitter ldquo; rattling rdquo; iso ring.
Troubleshooting: Check the engine oil pump no problem, even replacement oil pump drive chain and chain tensioner. After the test troubleshooting.
Review Analysis: Recall that the entire diagnostic process, because the accelerator pedal no abnormal noise when removing the compressor tape, leading to the diagnosis of the author in the wrong direction. In addition, the car is very normal in the cold and road test, no abnormal noise, and found no abnormal engine and take a lot of detours.
(Yu Hongjian)