Electronics Question

[Afunk]

Hey,

This question is mostly targeted towards NA-T people with GTE electronics. Although it is rather unique, if you know about simple electrical currents I'd appreciate your help.

I have been throwing a code 52, short in knock sensor circuit, for some time now. I have replaced everything- new shielded wiring up to ECU, new clips and connectors, and finally a new $157 knock sensor.

The thing is, I'm NA-T with GTE electronics, meaning I have to run the two knock sensor inputs to the ECU to the single knock sensor (other knock sensor holes where turbo KS's are usually are not pre-drilled).

My car ran fine without codes for about 6 months by just splicing the 2 stock KS wires together right before the single knock sensor and plugging it in there. When it started throwing the code, I thought it might just be the old wires so I replaced that, and then the clips, and now the new KS.

I was reading up on the internals of the KS with it's vibrating crystal to make a AC voltage and noticed it runs through a resistor inside the KS. Do you think that since I only have half the resistance that the turbo ECU is used to, it throws the code?

That hypothesis would not explain the fact that it ran fine for 6 months. The resistance of the stock wires and the new wires was determined to be almost non-existential so one can not say that some resistance came from the old corroded wires to make up for the missing resistor.

Thanks alot,

Alex

 

[Bishop92t]

I don't have any direct experience with your situation. But personally I would do whatever it takes to get a 2nd knock sensor in there. Use two wires and two sensors just like stock. If that doesn't fix it I would bet the problem is your rewiring. I've seen rewire jobs fail immediately as the ECU is very picky about the knock sensor setup.

 

[Afunk]

I don't have any direct experience with your situation. But personally I would do whatever it takes to get a 2nd knock sensor in there. Use two wires and two sensors just like stock. If that doesn't fix it I would bet the problem is your rewiring. I've seen rewire jobs fail immediately as the ECU is very picky about the knock sensor setup.

Thanks for the quick reply, the thing is, I have no where to put a second knock sensor as the holes are not predrilled on the NA block. I can not get a drill in there to tap it either. I tried building a bracket to adapt it to one of the other pre-existing tapped hold (for the AC bracket or something) but the computer didn't like that and immediately threw the code.

 

[Afunk]

BTW, do you know if there is a resistor inside the ECU? Projectsupra1 suggested the idea that if there was a resistor inside the ECU, after all those months of running with one knock sensor it simply burnt out the resistor inside the ECU (if there is one). I think my next step might be to try a known working ECU.

 

[Bishop92t]

Interesting. The car shouldn't really care where the sensor is mounted as long as it gets a good signal. Perhaps your bracket or mount point was not allowing a good ground through the block?

 

[Bishop92t]

Not too sure about the internals of our ECU. If it burned out yours then likely it will just do it again with a new ECU.

 

[Afunk]

Yeah, I'm thinking my plan will be to first try out another ECU as it is the only thing I haven't touched, and then going back to the two knock sensor setup as I now have a new KS and one that is known the be operational

 

[Afunk]

Could someone please tell me the voltage potential between the block or any other grounded point, and the knock sensor's ECU input wire (green plug terminal).

Thanks alot

 

[nissota]

Have you checked for continuity between the computer terminal and the knock sensor terminal so see if the knock sensor wire has been severered?

Have you checked for continuity between the knock sensor connector and ground? This would determine whether or not the knock sensor wire shielding has been damaged and the knock sensor signal wire is coming in contact with the shielding core.