2011 Expedition No power very sluggish

[ucsutah]

When I purchased it a couple of years ago the old engine had 240k, they put a newer engine in it that was about 100k and it didn't have much power. Going up hills, pulling trailers etc very sluggish and lags when trying to accelerate. I was hoping to buy a trailer to pull a max weight of 7k. It drives okay to commute, but big hills or pulling something heavy major issues. I have a Ford 2013 ford f-150 and I believe they have close to the same engine, and my truck has so much more power and acceleration. I am going to sell my truck but I need this expedition to have the same power as my truck.

I had it diagnosed, check the engine light was on and showed code p0420, and found the right/bank 1 catalytic converter is at fault. They said it could be restricting the exhaust which would cause a lack of power?

My question is in your opinion do you think this is what the cause is and I get this replaced and would fix the problem? I don't remember having a catalytic converter issue at the beginning and still having these issues. I was thinking they put the wrong engine in it or something. Also, gas mileage is really bad as well.

 

[Timo2824]

The 2013 f-150 has a 5.0L V8, your expedition has a 5.4L V8, other than a similar block they are very different engines. A clogged catalytic converter will definitely cause a power loss, sometimes engines won't even rev above 3,000rpm with a clogged converter. The mechanic should be able to do a pressure drop test across the converter to prove if it's clogged. Another thing you can do is just unbolt the cats and drive down the highway to see if the engine runs better. This is kinda dangerous because CO can leak into the cabin, but I've done it before on an e-series van to prove to my boss the cats were clogged. Also, if you like your neighbors, don't do this late at night because it's very loud.

 

[Modelcarguy]

Did you remap the computer when you dropped the new motor in?

 

[ucsutah]

The 2013 f-150 has a 5.0L V8, your expedition has a 5.4L V8, other than a similar block they are very different engines. A clogged catalytic converter will definitely cause a power loss, sometimes engines won't even rev above 3,000rpm with a clogged converter. The mechanic should be able to do a pressure drop test across the converter to prove if it's clogged. Another thing you can do is just unbolt the cats and drive down the highway to see if the engine runs better. This is kinda dangerous because CO can leak into the cabin, but I've done it before on an e-series van to prove to my boss the cats were clogged. Also, if you like your neighbors, don't do this late at night because it's very loud.

Thank you for your response I will check the catalytic converter and get a pressure drop test done by a mechanic.

 

[ucsutah]

Did you remap the computer when you dropped the new motor in?

I really don't know I bought it from somebody at that time that put the newer motor in. Do you think that would cause the issue? How would I go about remapping or check that is was remapped? thanks

 

[Modelcarguy]

That’s either buy forscan or visit the dealer to make sure you have the correct map for this motor.

 

[Brons2]

The 5.4 3V is not exactly fast, this is a 310 HP engine in a 6000 lb SUV. I would call it adequate, no more. Both the Ecoboost and the GM 6.2 are rocketships compared to the 5.4 3V, I drove both before buying mine. Of course if you have an issue it's going to be worse. I assume you have tried the basics? New plugs, new air filter, check codes, etc. I echo the other poster's recommendation to get Forscan.

 

[Modelcarguy]

To make this problem a bit clearer - every engine these days are computer controlled. From variable valve timing to shift points, emissions, O2 intake, fuel mapping and on and on.

So unlike the old days - jerk the motor, replace it with something close, bigger or smaller and turn the key, unless the replacement engine was identical to the one removed your mapping will be wrong.

We had a similar issue with our 08 I had to replace the instrument cluster. Turns out, the mapping was incorrect with the replacement part. Couldn’t figure out why. Changed and checked a lot of stuff.

Finally gave up and went to Ford. Turns out the part number on the cluster was correct, but it was assigned to a new up graded part that was incompatible with the cars map.

Then on top of it - two weeks after our truck was built in 08, Ford changed the installed mapping to suit the new part with the same old part number.

It took Ford Engineers in Detroit and the dealer work together over four hours to figure out the problem.

Truck runs fine now. But this shows how sensitive an engine swap could possibly be. If the guy you bought from did the swap and no new map, you need to get the correct one for the replacement motor before dropping the dime on an additional boat load of parts.