Working on the 2.4 engine swap in my son's Camry, the yard cut three arms of the wiring harness that runs from the intake/engine to the fuse box, leaving dozens of wires to splice. Please tell me there is an easier solution....

 

What?

The new engine has the harnesses cut? Was this done to remove it from the parts car by the yard?

Doesn't the car the engine is going into have an intact harness?

 

Our car was running and complete until the engine went south, of course. What is the preferred method for disconnecting between the engine and fuse box? We have a mass of cutoff wires on the new engine, and no readily apparent disconnect point on the car.

 

The bad engine is still in the car?

You will not be disconnecting wires from the fuse box but from the ECU.

You have two options.

One is to disconnect the wiring at the ECU. This requires removing the glove box to access the computer. Then disconnecting the electrical plugs.

Then removing the protective electrical tape and bellows at the firewall to allow pulling the harness plugs through the firewall.

If going this route most of the wiring will stay connected to the engine/trans. However there will still be grounding wires, etc that run from the engine to chassis.

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The other options is disconnect the wiring to the engine and trans. Most of the wiring is connected via plugs to sensors, etc except for ground wires.

If going this route mark every disconnected wire and perhaps take photos.

Since the harness with the new engine is effectively wrecked but cutting (suggest not splicing or may be asking for trouble). One of the two options is suggested.

Unplugging has its advantages as one can just swap one for one, the cut wiring individual connections to the sensors, etc with that of the now removed wiring harness. Then install engine/trans.

Suggest you look closely at the replacement engine for hidden items (back side of engine) having vacuum hoses and or wiring connected to them. You want to remove all connections to the engine/trans when it is removed to prevent damage to the part it still may be connected to.

 

Thanks, Joey, you obviously are much more knowledgeable on these cars than I am.


The ECU disconnect behind the dash was simple. The mass of wires coming from under the engine cover on the driver side of the engine compartment is the problem...is there a disconnect somewhere in there? I can't believe Toyota procedures for R&R'ing these engines does not address this, but I can't find it yet if it does.

 

On the drivers side one bundle goes through the firewall and has plugs. Another goes to the fuse box and has no plug.

Toyota most likely connected this wiring to the engine. Once the engine was installed the fuse box was attached to the chassis.

 

The pic is the mess of wires coming out of the engine. Everything is still intact on our car. Even if I disconnect from the fusebox, I still have to, apparently, rewire everything from the existing harness into the new engine??? That appears impossible to me. I can't believe there is no factory disconnect outside of the engine. Toyota mechanics can't possibly have the time to completely rewire every one of these engines they replace!

 

Most engine swaps involve disconnecting the harness wires at the engine and leaving the harness in the car. Then installing the replacement engine and reconnecting the wiring at the engine.

The salvage yards cutting of the harness was to expedite the engines removal. Plus they assumed the above engine replacement process would be used and there was no need for another harness.

Most used replacement engines don't come with any of the harness. Some don't even come with sensors, etc which must be swapped.