What ECU Can I Use For 4.0 Swap?

[Panzer Captain]

I searched but couldn't find the info I need --- what ECU's can I use for the 4.0 swap?

My 4.0 drivetrain is coming out of a 2/95-built 540, so it has EWS-II. I can't use that ECU, can I?

Will the ECU out of a car other than an E34 work?

[bimerguycw]

I swapped my 530iA engine using a 740i and it's wiring harness and ECU and it worked well. As a matter of fact, I checked with a few others and found that I could even use ny 530iA ECU(which is mapped a little differenly) and it ran okay for days so I kept it as a trouble shooting part just in case I need to eliminate the ECU as a future problem.

I searched but couldn't find the info I need --- what ECU's can I use for the 4.0 swap?

My 4.0 drivetrain is coming out of a 2/95-built 540, so it has EWS-II. I can't use that ECU, can I?

Will the ECU out of a car other than an E34 work?

[bimerguycw]

I swapped by 3l for the 4L when I found a bad Cyl #1 and is was more cost-effective to replace with a good low mileage 4.0L than to repair the cyl #1. And I get more HP/torque with the package. I just need to be a bit more gentle with my AT from the 3.0L.

If your 3.0L needs something other than the bottom end I have a good remainder of parts that have only 12k Miles on them such as cyl heads complete.

Good luck with the swap and I would be glad to add any tips about the swap if you request.

[Panzer Captain]

I swapped my 530iA engine using a 740i and it's wiring harness and ECU and it worked well. As a matter of fact, I checked with a few others and found that I could even use ny 530iA ECU(which is mapped a little differenly) and it ran okay for days so I kept it as a trouble shooting part just in case I need to eliminate the ECU as a future problem.

Thanks for the info!

What year 740i did the ECU come from?

Are you SURE you can use the 3.0 ECU? And are you SURE that it won't do any damage to the engine? I would hate to damage my newly-installed 4.0 as a result of being fouled by the ECU. Of course, I don't know if that's even possible... ?

[Panzer Captain]

I swapped by 3l for the 4L when I found a bad Cyl #1 and is was more cost-effective to replace with a good low mileage 4.0L than to repair the cyl #1. And I get more HP/torque with the package. I just need to be a bit more gentle with my AT from the 3.0L.

If your 3.0L needs something other than the bottom end I have a good remainder of parts that have only 12k Miles on them such as cyl heads complete.

Good luck with the swap and I would be glad to add any tips about the swap if you request.

That's exactly what I'm doing --- swapping the 4.0+6spd out of a rollover '95 540 into my '94 530iTA.

The 4.0 is in GREAT condition, Alusil, and runs like a dream.

Actually, the 3.0 in my car is also in great condition and runs like a dream. Nikasil, yes, but verified via leakdown that it is in excellent condition --- a result of spending it's birthing years in Europe, away from the sulfur-tainted gasoline. I don't need the 3.0, after the swap is complete.....

I'm also going to use the M-Tech sport springs and swaybars, and brakes, out of the 540 in my 530iT. Short shifter out of an E36 M3.

[bimerguycw]

So, you're going to the 6-sp from an Auto, urgh...that sound like more tham I was willing to do to make the 3rd pedal clutch and all that or are you keeping the AT from the 3.0L?

What model AT is in your 3.0L?

[Panzer Captain]

Yeah - I have a complete running / driving / working 540/6 that I got for cheap, so I just had to do it

I don't recall the exact AT in my 530 --- but it was recently gone through by Kurt Koeller and is in fantastic condition, very smooth and shifts great --- the PO is a member here, Geoff (530iTouring).

[Panzer Captain]

I swapped my 530iA engine using a 740i and it's wiring harness and ECU and it worked well. As a matter of fact, I checked with a few others and found that I could even use ny 530iA ECU(which is mapped a little differenly) and it ran okay for days so I kept it as a trouble shooting part just in case I need to eliminate the ECU as a future problem.

What serial # ECU do I need to use?

[bimerguycw]

As for the ECU/DME to use with a M60B40 I used the 0 261 200 404 from a 740i car which means it was mapped for the proper 4.0L engine vs. the 3.0L which has the same ECU number.

Also, You need to get all the intake portion of the 4.0L to use the full intake air and MAF that are different between the 3L and 4L.

My Engine cover is in good condition, say 8 out of 10 and I'm in NC.

[Panzer Captain]

Does the ECU need to be out of a manual tranny car? Or doesn't matter?