ECU "Married" To Vehicle?

[Greg Davis]

Sorry if this has been covered - I'm at work and can't spend much time searching.

My daughter's rig ('03) seems to have lost a liner and/or head gasket. My rig ('00) has a solid 4.0 in it. Here's my question.

Can I put my 4.0 in her rig to keep it on the road and then rebuild her 4.6 at leisure to put in my rig? Will the ECU's need to be swapped, or can they even be swapped from rig to rig?

Thanks in advance,

Greg

 

[Timmy!!!!!!!]

I believe in testbook you just have to switch a setting from 4.0 to 4.6 and vice versa.

 

[Drillbit]

4.0 and 4.6 ecus will run the other motor without and issue. Leave the ecu from her Rover in it and it will run a 4.0 without issues. If you swap ecus you need to either sync it with real software (rovacom, autologic etc) or do a "brain transplant" where you swap the ECU, BCU and cluster. That will put the mileage off of the Rover it came out of on your vehicle.

 

[BackInA88]

I assume the 4.0 is NON-secondary air and the 03 4.6 is?
Maybe a issue?
Not an expert it maybe be something you can have someone turn off in the ECU (with proper equipment) and at that point you might as well have them tell the ECU it's running a 4.0.
Or you could swap on secondary air injection heads to the 4.0 but at the point the engine is half apart.

 

[Drillbit]

I assume the 4.0 is NON-secondary air and the 03 4.6 is?
Maybe a issue?
Not an expert it maybe be something you can have someone turn off in the ECU (with proper equipment) and at that point you might as well have them tell the ECU it's running a 4.0.
Or you could swap on secondary air injection heads to the 4.0 but at the point the engine is half apart.

I forgot that, yes you are correct. SAI to SAI Non SAI to Non sai is no problem. You can't really swap a non sai engine into an SAI truck

 

[squirt]

Just want to throw this out....

If you're just looking to keep your daughter's truck on the road, you can use the non-SAI engine intact with plugs and the only issue will be a CEL. It will still run and drive just fine.

 

[SMLE]

I just did this exact thing:


https://discoweb.org/index.html


If the link above doesn't work, search "4.6 / 4.0 swap"


My 4.0 from a '96 Disco 1 was a GEMS, the '03 Disco 2 was a BOSCH.


I left the non-SAI heads on and just plugged the vacuum lines.


Swapped out the timing gear/chain assembly, the crank position sensor and mount.


Runs good, and I'm almost back on the road.


I did NOT move the ECU.

 

[Greg Davis]

Just want to throw this out....

If you're just looking to keep your daughter's truck on the road, you can use the non-SAI engine intact with plugs and the only issue will be a CEL. It will still run and drive just fine.

That would kill getting it inspected wouldn't it? Any way to tell the ECU to not look for the SAI?

 

[Greg Davis]

I just did this exact thing:


https://discoweb.org/index.html


If the link above doesn't work, search "4.6 / 4.0 swap"


My 4.0 from a '96 Disco 1 was a GEMS, the '03 Disco 2 was a BOSCH.


I left the non-SAI heads on and just plugged the vacuum lines.


Swapped out the timing gear/chain assembly, the crank position sensor and mount.


Runs good, and I'm almost back on the road.


I did NOT move the ECU.

Any CEL for not having SAI installed?

 

[discostew]

I assume the 4.0 is NON-secondary air and the 03 4.6 is?
Maybe a issue?
Not an expert it maybe be something you can have someone turn off in the ECU (with proper equipment) and at that point you might as well have them tell the ECU it's running a 4.0.
Or you could swap on secondary air injection heads to the 4.0 but at the point the engine is half apart.

Do the head swap like BackInA88 said. That wont take that long with the engines out and on the floor or stand if you have one. Probably cost a couple hundred or less for gaskets and bolts. Heads are more than likely leaking any damn way.

 

[KyleT]

You can also swap All the computers and cluster and iirc it will run with no sai. But I'm not 100%

All meaning the ecu, trains control module, slabs, bcu, and the cluster.

 

[Greg Davis]

You can also swap All the computers and cluster and iirc it will run with no sai. But I'm not 100%

All meaning the ecu, trains control module, slabs, bcu, and the cluster.

Is this mandatory? I'm looking for the easiest route and want to retain as much as possible in my 2000 so I can then rebuild the 4.6 to go into it.

 

[discostew]

The easiest way in my opinion would be to swap the heads. Cause what ever you do your going to have to do twice. Just keep the heads with the original trucks. Better than all that messing around with all the modules.

 

[BackInA88]

The easiest way in my opinion would be to swap the heads. Cause what ever you do your going to have to do twice. Just keep the heads with the original trucks. Better than all that messing around with all the modules.

Besides your going to need your NON-SAI heads for the 4.6 after you rebuild it for your rig.

 

[Greg Davis]

So just put the 4.6 heads on the 4.0 and all is good? That sounds pretty straightforward..

 

[squirt]

If you're going to be swapping heads, that sort of defeats the purpose of the swap, right? Just do the HG's on the engine that's already in the truck... ? If you're fearing a dropped liner, just pull the heads off while the engine is still in the '03, and the path will become obvious.

 

[SMLE]

Any CEL for not having SAI installed?

Yep, afraid so.


But it was the quickest, easiest and least expensive way of getting the '03 back on the road.


Plus, it leaves the 4.6 SAI heads available for the eventual complete rebuild without any additional down time on the vehicle, other than reinstalling the 4.6 of course...

 

[Greg Davis]

If you're going to be swapping heads, that sort of defeats the purpose of the swap, right? Just do the HG's on the engine that's already in the truck... ? If you're fearing a dropped liner, just pull the heads off while the engine is still in the '03, and the path will become obvious.

With the dropped liner, the engine has to come out. Hence just dropping the 4.0 in and building the 4.6 for mine.

 

[squirt]

With the dropped liner, the engine has to come out. Hence just dropping the 4.0 in and building the 4.6 for mine.

Got it. Sounded like you still weren't sure of the failure in the first post.

 

[discostew]

So just put the 4.6 heads on the 4.0 and all is good? That sounds pretty straightforward..

I think so. If its early heads then they used to have us run a reamer thru the exhaust guides to make them like 7 microns larger. And I haven't seen a straight head in a long time so getting them decked wouldn't hurt either. But that's all pretty optional I suppose.

I really think that's the most straight forward answer to what your trying to do. I would believe Marty on the ecu's working regardless of 4.0 vs 4.6 being in it. 6 tenths of a liter isn't much difference.