A couple months ago my wife's car wouldn't start. It took me almost a week to find out that their was a butt connector that was burnt up under the TIPM, I cut the burnt ends and re-crimped a new butt connector on and it started right up. A couple days ago the van died while she was driving and we had to have it towed home. I lifted the TIPM and once again the butt connector was burnt up. So now i had to add an extension piece w/ 2 butt connectors and once again it started right up. What could be causing this wire to burn up?

 

That’s most likely the fuel pump supply - the color is right but you should verify by checking voltage on the wire by pulling the fuel pump relay or fuse with the engine running. If you lose voltage on the wire by pulling the fuse, that’s definitely it.

Are you sure the first time you replaced it that it was just a butt connector and not a fusible link?

The most likely reason it’s happening is the fuel pump is pulling excessive current which could be due to the pump beginning to fail or there might be a restriction in the fuel line forcing the pump to work harder.

The easiest way to determine if it’s the pump is by checking the pump’s current draw with an oscilloscope. The waveform will show irregularities if there’s a problem. You can do a thorough visual inspection of the fuel lines for kinks or pinch points but it wouldn’t show internal restrictions. While doing so you can also inspect the wiring harness for damage or other tampering which could also be a cause.

Whatever the cause, I’d advise running a new wire from the TIPM to the pump - the heat damage to the other wires in the bundle tells me that wire has gotten far too hot to be dependable in the long term.

 

The common cause of wire burning is loose and improper connection or over sizing the overcurrent protection device. When repairing a heat damage wire one has to cut the wire back till all visible heat damage copper is removed I'd like to go an extra 1/2 inch to make sure clean new copper is used for the repair. I rather use the soldered western tap method using 60/40 rosin core solder or quality barrel lung with proper crimping tool covered with heat shrink. The trouble with butt connectors is people choosing the right size you see some with strand of wires cut or simply hanging out of the butt connector to make them fit well if you're reducing the cross sectional diameter of the wire it's current rating capacity is reduced or a too large of connector will cause a loose connection also proper crimping pliers needs to be used. The described wire is the fuel pump wire check the size of fuse to make proper size is used 20 amps check connector pin to make sure of no heat damage and always make the least possible splice into the circuit.