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2005 Ford F-150 - Two thrown rods!

Threw a rod in my 2005 Ford f150. Put another engine in it did the same thing 10 minutes later. mechanics says same cylinder #3 getting to much gas. What would cause that.

I would say a mechanic who doesn’t have a clue.

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3rd cylinder getting to much gas. Locked motor up. Put a used one in 125000 miles per the mechanic it Locked up after running for about 10 min per mechanic. What would cause this

Unless a fuel injector is hanging open and flooding the cylinder which is then leading to a hydrolocking situation is my initial guess. It would seem a bit premature to throw a rod though. Hydrolocking usually stalls the engine and may (or may not) lock the engine up and lead to a bent connecting rod.

This is assuming the No. 3 cylinder too much gas diagnosis is correct.

What parts from the old engine were moved to the new one?

To not notice that the engine had lots of liquid gasoline in the pan, with a compression-bent rod…get a new mechanic.

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I was told no parts from the old engine was used.

The engine control computer sets duty cycle on injectors. Check output to all injectors but especially #3. It might be shorted output.

Did you see a broken connecting rod? If an injector is flooding a cylinder that can cause the engine to hydro lock but not necessarily cause damage.

Some years ago the used car department where I was working sent a Dodge Durango to the main shop to have a “seized” engine replaced. The tech next to me installed the provided used engine, it didn’t start initially, he reconnected something that was left off and the ignition had been on for a minute before he tried to start the engine again. When he tried to start the engine the second time the engine was locked, just like the first engine. I told him that I could hear an injector buzzing while the ignition was on and to remove the spark plugs the try to turn the engine over. He found one of the cylinder filled with gasoline.

The problem in that case turned out to be a shorted injector driver in the PCM causing the injector to stay open and flood the cylinder. None of the two engines were seized, the used car department relied on the brief inspection by the used car mechanic and I believe that the PCM was still under warranty.

I’m guessing Nevada above is correct, either there’s a problem with the engine computer or the wiring harness. If either of those remain the same as were in the pre-engine change vehicle, that’s where I’d look. The only other thing I could guess is some sort of problem with the transmission or drive train, and the number 3 failure in common is just a coincidence. It’s usually pretty easy to disconnect the driveshaft, so do that when first testing the next engine. Harder to disconnect the transmission, but should be able to verify the trans input shaft turns freely in neutral, so start by testing in N. Make sure the spark plug/cop wires are connected correctly of course.