Code 118 puzzle
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Mountain Pass
Joined: Mar 2008
Posts: 166
Likes: 38
From: SW GA
Code 118 puzzle
So after a lot of correcting past neglect, upgrading injectors I am down to a single KOEO code of 118. ['94, 5.0l, 4r70w, air pump delete] The ect sensor was replaced as it was old and not giving correct output. New one is reading about 5.3 Ohm at operating temp. However, code 118 indicates an over voltage or the temp as too high. Un plugged sensor and I get 5v on one side and .4mV on the signal side. I was not expecting voltage on the signal side so is that why it is reading overvoltage? I have opened the computer and it appears new as the truck only has 97k original miles. Looking at diagrams it seems the knock sensor shares connector with ect sensor. Is it possible something is backfeeding?
Last edited by generalee; May 30, 2025 at 07:48 AM. Reason: Left off vehicle info
Logistics Pro
Joined: Nov 2013
Posts: 3,928
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From: Mojave, Ca
So after a lot of correcting past neglect, upgrading injectors I am down to a single KOEO code of 118. ['94, 5.0l, 4r70w, air pump delete] The ect sensor was replaced as it was old and not giving correct output. New one is reading about 5.3 Ohm at operating temp. However, code 118 indicates an over voltage or the temp as too high. Un plugged sensor and I get 5v on one side and .4mV on the signal side. I was not expecting voltage on the signal side so is that why it is reading overvoltage? I have opened the computer and it appears new as the truck only has 97k original miles. Looking at diagrams it seems the knock sensor shares connector with ect sensor. Is it possible something is backfeeding?
0.4mv is basically nothing, and probably the resolution of the multimeter, so I wouldnt worry about that number.
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Mountain Pass
Joined: Mar 2008
Posts: 166
Likes: 38
From: SW GA
Rechecked the ect and at 80 deg I was getting 29.4 kOHMS so that rolled out the sensor. I removed it and used a couple of pigtails to test when powered from computer to see what was reporting as signal and the voltage was practically identical. So I suspected the connection was the issue and I cleaned the sockets and used a pick I have to swell the pins out slightly (don't recommend trying that) then decided to apply a tiny amount of copper anti-sieze in each socket and re-installed. Started right up and idled calm for about a minute and then it started coughing and wheezing and died. I sprayed cleaner in man thinking that might help but nope. Then as I restarted it and sprayed more cleaner in I noticed it run better w/ the spray so I un-plugged the maf and now it acts like a new truck. Drove it to town and back with it unplugged so that's it.
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