Knock sensor malfunction: Did a mouse cause it, or Seafoam?

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Jul 24, 2005
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199
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MA
 
 
 
I spent a little time this evening before "Lost" came on to try and figure out why my knock sensors keep turning on the MIL. I pulled the battery cable last Friday and went a couple days without it on, but now it is back again.

My first thought was that this was caused when I added a can of Seafoam (1/3 to oil, 2/3 to fuel, none to PCV because I didn't want to smoke up the neighborhood since I just moved in :) ) I couldn't find a lot of info on what to do about that though and it seems like that problem usually alleviates itself, which mine has not.

So today I went about it the FSM way. Since both sensors are indicated as being faulty, I doubt they actually both went bad. Also, since the engine has been running great, I know it is not actually knocking. Therefore, I figure it has to be some problem with the wiring.

This is where the mouse comes in. While removing the glove compartment to get at the ECU, I noticed some insulation looking stuff, like the kind you can shoot into your attic. I though that was odd, but maybe it was there to insulate the ducts or something. Then I noticed the tail of a mouse. This guy was real tough to remove as he was more or less mumified. The car never smelled, so I think he must have gotten in there during this past winter and freeze-dried himself. The truck was outside in NY all winter and wasn't really driven long enough for a frozen critter to thaw. However, if he was in there this long, it seems dubious that the wiring he would have chewed through would no short out. Either way, I was unable to get all of the mouse house out of there so am setting about removing the dash to clean this up.

I figure while I have the dash off I'll hook in a CDL switch and maybe a CB. Anything else good to put in the dash? Anyone know how to remove the dimmer switch from the panel too? It's tough to drive around at night without an illuminated dash. :frown:

Lastly, what harnesses make up the connection between the sensors and the ECU? Since both knock sensors are freakin' out and nothing else, I figure it must be somewhere where they are the only two wires together, but from what I can tell they are bundled together with a ton of other things the whole way. I doubt this mouse was smart enough to pick out the two knock sensor wires in the bundle and bite through both of them.

Hopefully I can solve this issue without shooting myself in the face with the passenger side airbag.
 

re_guderian

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Jun 17, 2005
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Arizona
 
 
 
Pete483e483 said:
I Lastly, what harnesses make up the connection between the sensors and the ECU?

Hopefully I can solve this issue without shooting myself in the face with the passenger side airbag.
...or getting the Hanta Virus... But it might help to know what year your truck is. The EWD is very helpful for this. I have a '95 EWD that I can look in, if that's close to your year...
 
Joined
Jul 24, 2005
Messages
199
Location
MA
 
 
 
Mine's a 97. I have the EWD as well, but I am having a tough time relating the diagram to the engine compartment, plus I can't really figure out where the K2 goes on the diagram since the drawing is so small.
 

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