2.9 eec

[chavo6723]

I have been having alot of problems with my engine running rough and not running at all. I have been digging through wires and relays. I cracked open my eec to find that pin 46 was fried. I know multiple things run to this pin since it is a signal ground. What could cause this to burn up so it doesn't happen again when I get a new one.

 

[franklin2]

Look at the oxygen sensor wiring. Make sure the wiring is not melted near the exhaust pipe.

 

[rusty ol ranger]

Honestly it was probably fried from within the ECM.

Pop it open and have a look

 

[chavo6723]

Could really use some help. My eec keeps frying at pin 46. I've ran through every single wire twice. I've checked every sensor and replaced them all 3 times. All my grounds are good. Im not sure if it could be the relay or maybe the wrong gauge of wires. (Somebody already replaced a bunch of wires). Running out of ideas here. All the fusible links are new. Can't pull any codes cause the eec gets fried. Anything would help at this point.

 

[franklin2]

Here's your old thread on this subject.

Thread '2.9 eec'

Jan 24, 2026

I have been having alot of problems with my engine running rough and not running at all. I have been digging through wires and relays. I cracked open my eec to find that pin 46 was fried. I know multiple things run to this pin since it is a signal ground. What could cause this to burn up so it doesn't happen again when I get a new one.

• chavo6723
• 2.9 eec eec computer emission rough idle and running
• Replies: 7
• Forum: 2.9 Liter Forum

 

[chavo6723]

I put a new 02 sensor connector on before all this happened. Could the new connector be pinned wrong? Does anyone know which wires will go to the heater and which one is the signal wire? I got 3 wires on a 4 pin connector.

 

[franklin2]

I put a new 02 sensor connector on before all this happened. Could the new connector be pinned wrong? Does anyone know which wires will go to the heater and which one is the signal wire? I got 3 wires on a 4 pin connector.

Why don't you leave the O2 sensor unplugged and run it like that for awhile and see if the problem comes back. The truck will run with the O2 unplugged, it will just throw a code for it and use the factory fueling tables stored in the computer to run the engine.

 

[SenorNoob]

That works.^

Half the guys in town are convinced having the O2 unplugged makes more power. They're nuts but it does run.