Rotting wires, was my Explorer a lemon?

[explodermann256]

2007 4.0L SOHC XLT. About to roll 123,000 miles. I really like this truck but it has been plagued with electrical issues since the day I got it. I am the second owner (was an umarked police car, got it from a police auction) and purchased it at 119k.

Anyways, when I bought it, it was discovered that the insulation on the wires leading up to the oxygen sensors on both sides of the truck was completely gone causing the truck to go haywire. Also, the wires leading up to the input speed sensor on the trans had the same issue causing the transmission to shift erratically. At first I thought it's possibly normal since the truck is 12 years old and things do wear out.....

But then, little by little more electrical gremlins began to reveal themselves. The wires leading to the coil pack? Crumbling. The wires leading up to the TPS? Hanging on by a thread and mostly free of any insulation. Alternator connector? Shot.

The truck always had a weird shake and felt like it was misfiring even though I changed the coils/plugs shortly after purchasing it. Last week it began to stall randomly and I pulled a code related to the MAF. I pulled back the tubing on the connector and wires only to find the harness had been repaired twice!!! Also, further back where the harness begins to run along the top of the engine, the insulation on the wires was completely crumbled. I replaced that harness only to find yet more bad wires. This time, it's the wires leading up to the EGR valve connector.

There’s probably more I haven’t even found yet.

Has anyone seen this issue on the 4th gens before? It can't be that the insulation on this many wires are bad, right? The wires under the hood are all nice and pliable on my 2005 Crown Vic, and same thing with a friend's '97 Exp Sport and pretty much every other vehicle I’ve owned that has been older than my Explorer.

 

[donalds]

Easy fix go to the junk yard and get a whole new engine harness

My guess is heat cycles got the wires

 

[boominXplorer]

Common issue for the late 06 to early 08 explorers. They are usually fine until they are disturbed, then they crumble. I'd get an 08+
harness and swap it in.

 

[JAWIT]

Yes, I've seen some of the wires on my '08 Mountaineer in similar condition, the ones going to the throttle body and TPS were especially problematic after I got it, so much so that it threw a wrench light on multiple occasion before I got the car lot where I bought it to replace them. Sine then, its been good to go as far as electric problems are concerned...knock on wood.

 

[PZaff]

2007 4.0L SOHC XLT. About to roll 123,000 miles. I really like this truck but it has been plagued with electrical issues since the day I got it. I am the second owner (was an umarked police car, got it from a police auction) and purchased it at 119k.

Anyways, when I bought it, it was discovered that the insulation on the wires leading up to the oxygen sensors on both sides of the truck was completely gone causing the truck to go haywire. Also, the wires leading up to the input speed sensor on the trans had the same issue causing the transmission to shift erratically. At first I thought it's possibly normal since the truck is 12 years old and things do wear out.....

But then, little by little more electrical gremlins began to reveal themselves. The wires leading to the coil pack? Crumbling. The wires leading up to the TPS? Hanging on by a thread and mostly free of any insulation. Alternator connector? Shot.

The truck always had a weird shake and felt like it was misfiring even though I changed the coils/plugs shortly after purchasing it. Last week it began to stall randomly and I pulled a code related to the MAF. I pulled back the tubing on the connector and wires only to find the harness had been repaired twice!!! Also, further back where the harness begins to run along the top of the engine, the insulation on the wires was completely crumbled. I replaced that harness only to find yet more bad wires. This time, it's the wires leading up to the EGR valve connector.

There’s probably more I haven’t even found yet.

Has anyone seen this issue on the 4th gens before? It can't be that the insulation on this many wires are bad, right? The wires under the hood are all nice and pliable on my 2005 Crown Vic, and same thing with a friend's '97 Exp Sport and pretty much every other vehicle I’ve owned that has been older than my Explorer.

I have an ‘06 xlt 4x4 and I have the same symptoms and I have spliced in new wire in several places. MAF, AC compressor, ESM (all six wires were bare) and coil pack. I would like to say that the symptoms are gone but that is not the case. As if the explorer is laughing at me. I haven’t seen so many wires with brittle insulation especially underneath the plastic conduit sleeve.

The codes I have been getting point to the Map sensor saying wrong atmospheric pressures and also too much air passing through egr at idle.

This is more like the computer doesn’t know what is happening and is simply identifying the symptoms.
the symptom is that randomly the egr is opening and causing the motor to not have the correct vacuum. I have cleaned the Egr system module and then replaced it with no change to the symptoms. I am at a loss.

 

[MotorCityFats13]

mine ran great when I bought it in 2014.... then decided to clean the throttle body and replace the air filter and it started to feel like trans problems shuddering from a dead stop then read about the wires and maf and tb were crumbling.... isolated the wires and painted on some liquid electrical tape and sealed that up with some duplicolor fake plasti dip and all has been well for the last 5 years