Knock sensor prob(CEL 52)/Tapping above 2500 rpm

[BlackDynamite]

Ok My 88 supra has a check engine light that shows up....code 52....(I've reset the ecu and checked wiring for a incorrect connection or physical damage...)
so the Check engine light does not come on when i start the car and let it run....the light does come on, Only when i rev above 1900ish RPM.....but i could drive around without it all day really slow and it wouldn't come on....lol...weird...i think the sensor is faulty...Now i also do have a tapping noise coming from the head around 2500 rpm...Now i know there is some type of tapping but this is kinda a splatter tap noise...there shouldn't be TOO crazy of wear and tear on a 50,000 mile head....To make this noise....It's Either the knock sensor retarding my timing(Because it feels like it's holding back on power....) or my spark plugs are not gapped right, etc.......but still not sure....any idea?:1zhelp:

 

[Nalleywhacker]

Ok My 88 supra has a check engine light that shows up....code 52....(I've reset the ecu and checked wiring for a incorrect connection or physical damage...)
so the Check engine light does not come on when i start the car and let it run....the light does come on, Only when i rev above 1900ish RPM.....but i could drive around without it all day really slow and it wouldn't come on....lol...weird...i think the sensor is faulty...Now i also do have a tapping noise coming from the head around 2500 rpm...Now i know there is some type of tapping but this is kinda a splatter tap noise...there shouldn't be TOO crazy of wear and tear on a 50,000 mile head....To make this noise....It's Either the knock sensor retarding my timing(Because it feels like it's holding back on power....) or my spark plugs are not gapped right, etc.......but still not sure....any idea?:1zhelp:

Dude iam having the EXACT same problem! Someone please help us out!

 

[supramacist]

Well..., I guess you have already pulled the codes.

All I'm going to say is hope the knock sensor doesn't need replacing.
They are right about 300 bucks.

There is nothing to them. You can see the largest part of it from it's location.

 

[BlackDynamite]

well i did a search and i came up with 150 bucks....300 maybe FRom dealer;]....i'll ask my cousin at the place where i got all my parts at...he normally can get me a good quality part for a good price...

 

[BlackDynamite]

189 from dealer and 180 from HorsePowerFreaks....i would have to pay shipping for Hpf....so the dealer it is...i can get a 10% discount off the dealer because of my cousin! YAy Cousin...It'll Be here wed and we'll see what happens!

 

[Nalleywhacker]

189 from dealer and 180 from HorsePowerFreaks....i would have to pay shipping for Hpf....so the dealer it is...i can get a 10% discount off the dealer because of my cousin! YAy Cousin...It'll Be here wed and we'll see what happens!

let me know it the new knock sensor fix's the problem.

 

[BlackDynamite]

Will do :]

 

[supramacist]

My dealer must be raping me!!!! Bastards.

 

[Fuzz420]

My dealer must be raping me!!!! Bastards.

No they rape everyone

 

[isnms]

The tapping you are hearing is not causing your code 52.
Code 52 is the status of the knock sensor circuit.
• Knock sensor circuit
• Knock sensor
• ECU

Most likely you have a wiring problem. You could have a bad knock sensor.
Did you test the sensor itself?

If you want to actually test the knock sensor itself, its pretty easy. The test is somewhat crude, but it should give you the results you are looking for.

1. Remove knock sensor from engine.

2. Hook up a volt meter to the knock sensor.

3. LIGHTLY tap on the sensor with a wrench or screwdriver.

If the volt meter spikes a little, then your knock sensor is working properly.

If it doesn't spike, check #2 above and repeat step 3. If you're sure it is hooked up correctly, and still no spike, then your sensor is bad.

Note: Knock sensors rarely go bad.

http://www.supramania.com/forums/showthread.php?t=4072&highlight=knock+sensor+test
http://www.supramania.com/forums/showthread.php?t=6590&highlight=test+knock+sensor

 

[Nalleywhacker]

hey black dynamite, when you put you head and everything back on did you have any extra connectors not plugged into anything? cause i have a little green connector thats not plugged into anything and come to find out thats my knock sensor connector! lol i feel like a dumbass! but yeah just thought id let yall know.

 

[BlackDynamite]

i hooked everything up, making SURE i didn't have any connectors left over....But i have the connector hooked up to the sensor......If a rewire is required where does is connect to so i can Run my own wire......if that is possible...i'm gonna check my spark plugs and wires first though....

 

[isnms]

Here are the SOGI rewire articles:
http://www.supras.com/06/techcenter/display.php?QID=51
http://www.supras.com/06/techcenter/display.php?QID=69
or check with shaeff for a premade kit:
http://www.supramania.com/forums/showthread.php?t=2943

 

[BlackDynamite]

what could be the tapping noise?

 

[BlackDynamite]

Also could i test the cable?

 

[isnms]

what could be the tapping noise?

could be injectors, they're kind of noisy
could be valves need adjusting
could be rod knock but that is not giving you the 52
could be other things..

Also could i test the cable?

sure you could test continuity from connector to ecu end but if it's an intermittent it may not show up.

 

[BlackDynamite]

Well i noticed that there was a ground connection on that harness...could i have missed a ground?

 

[BlackDynamite]

could be injectors, their kind of noisy
could be valves need adjusting
could be rod knock but that is not giving you the 52
could be other things..


sure you could test continuity from connector to ecu end but if it's an intermittent it may not show up.

well the valves were fine and i looked into adjusting them but there seemed to be normal wear...i check the shims and gapping....all the same....And i just rebuilt my motor...new oil pump, head gasket, etc....primed the system before starting..

 

[BlackDynamite]

so i doubt rod knock....i would think that it would start knocking or tapping before or around 800 rpm easy.....when ever i had rod knock before it would do it at idle....sounds like weird...someone said something about tranny...since it's auto...i'll check the fluid...

 

[BlackDynamite]

could be injectors, their kind of noisy
could be valves need adjusting
could be rod knock but that is not giving you the 52
could be other things..


sure you could test continuity from connector to ecu end but if it's an intermittent it may not show up.

Oh, and Injectors? How could they be noisy?....like physical sound they make rattling or somthing...or the noise of them injecting the fuel... l