GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: iamwills on 27 February 2010, 14:59
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hi my car would not go over 50000 rpm but seems to drive ok, so had the fault code red and came back with knock sensor. he said ihad run it a bit low on oil and that would nacker the sensor, so just to replace it and all will be well. but this morning i started car and it waz realy noise like a fanbelt noise but with a more of a rattle. seemd like bull bearings but mabey not. any way the noise goes when warmed up and will not hapen till next day. this noise started about a month ago from just a fan bell sqeek , just faught that a knock senser might be pic ing up that noise ,
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Timing belt one tooth out??
Car going into safe mode?
Do a search, loads of posts of car wont go over 5000k :smiley:
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would that cause the knock sensor to make the car go into safe mode/
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A faulty knock sensor will cause it to go into safe mode as it will affect the timing... The sensor won't make anything make a noise. All it will do is either cause the car to not to start, cut out or cause it to go into safe mode when running thus the 5k limit !!
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ok so would i need to replace the knock sensor, and have the timing reset. or would just replacing the knock sensor fix the problem.
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and do u no if there are two knock sensors thanks
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Get the timing checked ASAP.
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wot about the knock sensor. should i forget that, is the car ok to drive
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I wouldn't drive the car until the timing is checked.
Forget the knock sensor for now, find the root of the problem, which could well be timing.
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dont supose you can recomend any one in birmingham to do the job 4 me ,
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ok so if timing sliped would that evect the knock sensor. or would a faulty knock sensor evect the timing , , wot im trying to say is that if the knoock sensor was playing up would that cause the timing to go out and bring up the knock sensor , thanks again for all your help
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ok so if timing sliped would that evect the knock sensor. or would a faulty knock sensor evect the timing , , wot im trying to say is that if the knoock sensor was playing up would that cause the timing to go out and bring up the knock sensor , thanks again for all your help
If the knock sensor was faulty it would read the timing incorrectly. However before you replace the knock sensor get the timing checked to make sure everything is where it should be. If it is then think about replacing the knock sensor.
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ok if i get the timing fixed, and it is the knock sensor will it keep throwing the timing out.
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if you got a code for the knock sensor, then the ecu is reporting it faulty, non responding or reading way out of whack. That means usually that the sensor itself is faulty, especially if not in conjunction with other codes.
OBD is a diagnostic system to identify sensor or control faults, not to inform of running conditions in general but as a system check of all sensors.
The noise you describe may be getting picked up by a knock sensor, but that wouldnt trigger a knock sensor code, instead something like timing retardation figures in the ecu would change, the cel might come on for max timing retard reached but the code would be like "reading out of range", if its a fooked sensor of any kind you get "implausible signal or open circuit" type of codes (im generalising of course)
A knock sensor is a wee microphone and so can go open circuit, triggering a knock sensor error code. You should be able to check it with a basic ohm meter on low range - say up to 100 ohms. Any reading means its ok, its a little voice-coil so goes open circuit if faulty. This mic picks up sounds and that signal is fed thru a filter in the ecu analog inputs to look for the sounds of pinking or pre-ignition which have a specific range of frequencies that are known to be emitted from the cylinders when knock occurs. If knock is detected, the timing is retarded until it stops, or hits the limit. Then it goes to limp mode if the limit is reached, I know scoobs can pick up noise from a new oilfilter not filled yet on first start and trigger timing retard, possible wi the golf i suppose for other noises but unlikely as they are pretty accurate when working.
If the KS is showing as missing or faulty to your ecu, it will pull the timing back and go into limp mode as it cannot determine correct max timing advance any more.
Hope this helps mate ;)
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ok so if i start with a new knock sensor, if working right it will rev over 5000rpm thanks 4 all your help mate, as such a old car now im sure all the sensors will probly need replacing, thanks again
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the first sensor is directly infront of engine on lower blok. ware is the other ,,
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one is behind the alternator. the other is above the oil filter housing mate afaik
remember they have to be torqued down to the block at 25nm or they wont work properly...
;)
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ok thats great just one more question. a mecanic just told me ther is only one knock sensor on a gti 8 v. 2.0l . and ther is 2 on the vr6 is this right ,
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yeh thats right, if its an 8v then the knock sensor is on the front of the block
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ok thanks a lot , will post when i finaly get it over 5000 rpm .thanks again mate.