DataMaster and Knock Count
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Instructor
Joined: May 2014
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From: Fayetteville NC
DataMaster and Knock Count
94 Coupe
Observing and recording using DataMaster at idle and cruising, the Knock Count is constantly counting FAST - going to 65,535 and starting over. Knock sensor problem? Will a lifter tapping trigger the knock sensor(s)?
The engine is quiet and smooth at idle and cruise. To me the hydraulic roller lifters make more noise than standard hydraulic lifters at idle. I assumed the noise is the rattle from the lifter links that keep the roller lifters from rotating. Yes/NO? Would this trip the knock sensor(s)?
Observing and recording using DataMaster at idle and cruising, the Knock Count is constantly counting FAST - going to 65,535 and starting over. Knock sensor problem? Will a lifter tapping trigger the knock sensor(s)?
The engine is quiet and smooth at idle and cruise. To me the hydraulic roller lifters make more noise than standard hydraulic lifters at idle. I assumed the noise is the rattle from the lifter links that keep the roller lifters from rotating. Yes/NO? Would this trip the knock sensor(s)?
Last edited by afgunn; Feb 24, 2015 at 08:03 AM.
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From: Fayetteville NC
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From: Middletown Delaware
If you read the online Datamaster manual what you are seeing is normal. It states that on start up is where most counts will jump up very rapidly. The knock sensors are located on both right and left sides of the engine block below the cylinder heads about midway. They each have a small protective metal shield cover held on with two small bolts. You can view them from under the car looking up.
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From: Fayetteville NC
Thanks for the location info. I guess they are hard to get to from the top of the engine?
Last edited by afgunn; Feb 24, 2015 at 08:09 AM.
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From: WV
I do know that knock sensors have to be torqued properly or you can get false readings from the sensor...I have a friend that tightened his knock sensor without a torque wrench and tightened it way to tight..He got excessive knock counts until he removed the sensor and torqued it to spec, then all was well.....Maybe someone replaced the knock sensor on your car before you owned it and torqued one or both to tight....WW
Thread Starter
Instructor
Joined: May 2014
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From: Fayetteville NC
I do know that knock sensors have to be torqued properly or you can get false readings from the sensor...I have a friend that tightened his knock sensor without a torque wrench and tightened it way to tight..He got excessive knock counts until he removed the sensor and torqued it to spec, then all was well.....Maybe someone replaced the knock sensor on your car before you owned it and torqued one or both to tight....WW
Thread Starter
Instructor
Joined: May 2014
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From: Fayetteville NC
Found Knock Sensors
Thanks for all the help guys! Much appreciated!
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From: Middletown Delaware
I get knock counts constantly at idle or cruising. The counter is constantly counting, it never stops - 65,535 and then it starts again. The counter is counting very, very fast like every time a piston fires or faster.
Thanks for the location info. I guess they are hard to get to from the top of the engine?
Thanks for the location info. I guess they are hard to get to from the top of the engine?
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Joined: May 2014
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From: Raleigh NC
I dont have the info for that specific year, but be prepared to drain the coolant if you're taking out the KS. I know on the 90-91 you have to. Just a warning, unless someone with that year can speak differently.
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From: Fayetteville NC
Thanks. Yes it requires a coolant drain, and while it is drained, I will be replacing both Knock Sensors and a coolant hose that I need to replace.
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From: Fayetteville NC
Replaced the spark plugs yesterday and now there are no knocks at idle or cruise, but I have misfires at high speed - ~5000rmp. The spark plugs that I pulled out were all equally black and sooty. I am fairly sure that the engine is running too rich, but I am going to change the O2 sensors first since the car has ~76K miles and both knock sensors as well. I broke one, it stays connected but may not over time.
I pulled one of the new plugs today, and black sooty deposits are starting to build up. Again, this is further evidence that the engine is running too rich, but I do not think it is time to start tuning the engine. Need to make sure I have good knock and O2 sensors first.
I pulled one of the new plugs today, and black sooty deposits are starting to build up. Again, this is further evidence that the engine is running too rich, but I do not think it is time to start tuning the engine. Need to make sure I have good knock and O2 sensors first.
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From: Jyväskylä, FINLAND
Just have the KS ready in the other hand while taking the old one off. It leakes just a few drops if you are quick and have the coolant system sealed. As soon as you've got the new KS on the threads, it's a child'd play.
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From: WV
You can change the knock sensor without draining the coolant. But you must have the car quite high to get easy access to the KS. Just a few weeks ago replaced mine, took like one minute after the covering plate was out of the way.
Just have the KS ready in the other hand while taking the old one off. It leakes just a few drops if you are quick and have the coolant system sealed. As soon as you've got the new KS on the threads, it's a child'd play.
Just have the KS ready in the other hand while taking the old one off. It leakes just a few drops if you are quick and have the coolant system sealed. As soon as you've got the new KS on the threads, it's a child'd play.
This is the way I did my knock sensor, you only lose a small bit of coolant and it's much easier then draining the system...I didn't lose any more then an ounce of coolant doing it this way...I believe the fact that your opening up a small hole in a vacuum is what stops much coolant from leaking out, ( it's hard to drain from a vacuum) sort of like trying to pour from a gas can without opening up the vent....But , if you take off the radiator cap before pulling the knock sensor , then you'll get soaked with coolant....
....WW
Last edited by WW7; Mar 1, 2015 at 10:52 AM.
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From: Fayetteville NC
You can change the knock sensor without draining the coolant. But you must have the car quite high to get easy access to the KS. Just a few weeks ago replaced mine, took like one minute after the covering plate was out of the way.
Just have the KS ready in the other hand while taking the old one off. It leakes just a few drops if you are quick and have the coolant system sealed. As soon as you've got the new KS on the threads, it's a child'd play.
Just have the KS ready in the other hand while taking the old one off. It leakes just a few drops if you are quick and have the coolant system sealed. As soon as you've got the new KS on the threads, it's a child'd play.
Do you know the torque value for the knock sensor on my 94 LT1?
Last edited by afgunn; Mar 1, 2015 at 12:50 PM.
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From: Fayetteville NC
This is the way I did my knock sensor, you only lose a small bit of coolant and it's much easier then draining the system...I didn't lose any more then an ounce of coolant doing it this way...I believe the fact that your opening up a small hole in a vacuum is what stops much coolant from leaking out, ( it's hard to drain from a vacuum) sort of like trying to pour from a gas can without opening up the vent....But , if you take off the radiator cap before pulling the knock sensor , then you'll get soaked with coolant........WWDo you know the torque value for the knock sensor on my 94 LT1?
I googled and found 14 lbft, is this correct?
Last edited by afgunn; Mar 1, 2015 at 01:04 PM.
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From: Jyväskylä, FINLAND
That sounds about right.
I don't remember it anymore, it was a real pain to find in the FSM, but I'm certain that it was a relatively 'low' number, something like 20 Nm, which is very close to 14 lb-ft.