How do i put my knock sensor back together

[carcrazy144]

Hi
i just bought a 98 talon tsi about two months ago and the previous owner, for whatever reason, disconnected the knock sensor from the ecu. I have no clue where it goes and need help putting it back. But not only that, i just finished fixing my strut towers and went to get it inspected and when my mechanic hooked it up to the computer and reset my ecu, it came up with five errors. I think that this may be due to the knock sensor not being hooked up. Please help, i would like to get the car inspected but really can't because of the ecu problems.

thanks

 

[stevo911]

Was their ever an engine swap done? And what do you mean by unhooked? Is it hanging off the car or is only the harness unplugged?

 

[carcrazy144]

No, the car is completely stock. And what i mean by unhooked is more like she cut it off of the ecu.

 

[stevo911]

Sorry to ask this once more but did she cut the wire or flash it and remove knock? If it was the wire are both peices still there? Can it just be soldered back?

 

[carcrazy144]

I believe she just removed it but i don't know where it would go to check. It's still connected to the block, the wire is currently tied up around the intake and can be soldered back in. When i bought the car i was told that it was removed because it was sending false info to the computer saying it was knocking, when it actually wasn't, and it retarded the timing accordingly which supposedly made it run slower.

 

[snowborder714]

Which part of the wire was cut? The knock sensor plugs into an connector on the ECU harness. If it was cut on the ECU harness side, you'll have to find the two halves and solder together. If it was cut on the knock sensor side, you can also solder together or just get a new sensor.

 

[carcrazy144]

The part of the wire that goes into the harness/ecu was cut. It is still attached to the sensor in the block. I believe it has to go through the firewall and connect to the main harness, but where would that entry through the firewall be located?

 

[snowborder714]

Below the battery.

 

[stevo911]

If its connected on the sensor and disconnected at the firewall where is the other 3 feet wire? Must be floating somewhere in your dash reach around the harness on the ECU side the wire is probobly hanging there somewhere.

 

[carcrazy144]

Ok, so if i can find the other part of the wire in that sea of wires and get my knock sensor reconected, will that fix some of the other ecu errors i am having, if not all of them?

 

[snowborder714]

It all depends on what errors it was throwing. I don't think a bad knock sensor can throw 5 codes though. The guy didn't tell you what was throwing the codes?

 

[stevo911]

If the knock sensor is good. Has to be a reason why it was disconnected to begin with also what are the engine codes when hooked up to a scanner? Only way to fix the errors is to know what the errors are.

 

[carcrazy144]

i know that the fuel trim is one of the errors, i was looking for the code but currently can't find it. That's the main one my mechanic told me, then i took it down to advance to have all of the codes pulled and they didn't even tell me the codes, they just said the knock sensor, and the fuel trim. I don't even know what the fuel trim is or what it does.

 

[stevo911]

I beleive fuel trim is just a lean mixture? Snow we seem to posting over each other alot .

 

[carcrazy144]

alright, thanks everyone for the help. I'll have to check this out tomorrow to see if i can't put that back together. Just real quick, any idea of a general area i should look for the other part of the knock wire on the cabin side of the firewall?

 

[stevo911]

Follow the main wires for the harness they all leave the firewall together get someone under the hood to pull the wire slightly and look for movement under the dash.

 

[carcrazy144]

ok, but if the wire isn't even coming through the firewall anymore, how can i pick it out from all of the other wires? Obviously it would be the one cut, but just say there are more that could be cut or broken. How then would i find the correct wire? Or am i pretty much screwed in that position?

 

[stevo911]

Colour of the wire will be the same in the cabin and under the hood?

 

[carcrazy144]

Ok i went back and looked at where my knock sensor wire would go, found another problem. The wire that is connected to the sensor, that was cut from the wiring harness is not origional. My assumption is that someone went to replace the wire, but never completetd the replacement. Does anyone know what the origional color of the knock sensor wire is on a '98 talon? Otherwise i think im hosed.

 

[snowborder714]

See if this helps.
http://www.dsmtuners.com/forums/art...bay-electrical-connections.html#post151528363

 

[carcrazy144]

Yes, thank you very much that was very helpful. I greatly appreciate that link. ill have to save that for future reference.