ticking sound and loss of power when hot

[Comanchero87]

87 MJ 4.0 5spd. Runs like a champ for the first 5 miles then as soon as it heats up under any load it starts ticking like an exhaust leak and loses alot of power. The oxygen sensor and knock sensor wires were melted and have been electrical taped. Does this sound like symptoms of bad sensor connections? any help is greatly appreciated.

[cruiser54]

Fix the oxygen sensor wiring first for sure.

[maddzz1]

It is probably from the melted wires. When our trucks first start they run in a closed loop mode from a set of preset specs. Once they warm up they run in open loop mode and get info from all the sensors.

[HOrnbrod]

Most sensors (including the O2 sensor) use stainless steel wires in the harness for the lowest resistance and better conductivity. This can make it a little difficult to get a good solder joint using ordinary rosin core solder when splicing these wires. It's best to use an acid based flux if you're going to solder the harness wires. Even better to use a high quality crimp connector with the proper crimp tool. If you have just taped them together, this is most likely your problem because the computer probably isn't seeing the signals from the O2 or knock sensors and you are staying in closed loop.

[Comanchero87]

Was a dirty c101 connector, Bad ground to TPS, MAP, MAT. Modified ground harness and cleaned the C101 and fixed the problem