[nrussell22]

I bought a 2008 e93 328i that had previously been engine swapped with an n52. the car is of the sulev model and originally came with the n51. the car will crank, start, and run rough for a few seconds before shutting off. the car throws no DME codes and after a compression test, has good compression. after inspecting the ecu it has the msv80.1 which means it was NOT swapped when the n52 was put in. my question is will buying an msv80 ecu with a cas module fix my issue? would it make more sense to try and have the ecu shipped off to someone who can convert it to an msv80? im open to any suggestions/diagnostic recommendations as im mechanically inclined and do have access to inpa.

[StradaRedlands]

I'm sort of just thinking out loud here, but the big difference between the N51 & N52 is the N51 has a three stage intake manifold and a secondary air pump. So does your motor have the 3SIM on it, and does it have the air pump installed?
If yes and yes, then I don't think you need to mess with the ECU, there is something else causing the problems. If no to either of those, then maybe it would be easier to just re-install those N51 components?

[ctuna]

You might be able to just reprogram the DME.
You could get some gains out of the three stage input with the proper tune and turn it into a 330.

see Engine Forum for N52.

https://www.e90post.com/forums/forumdisplay.php?f=378

https://www.e90post.com/forums/forumdisplay.php?f=16

[Black_Ls1]

I’ve done a swap from N51 to N52. All I did was keep the intake manifold and the fuel injector and fuel rail from the N51. Didn’t have to do any DME swap or tune. The car has been running perfect for 6 months

[nrussell22]

Originally Posted by StradaRedlands

I'm sort of just thinking out loud here, but the big difference between the N51 & N52 is the N51 has a three stage intake manifold and a secondary air pump. So does your motor have the 3SIM on it, and does it have the air pump installed?
If yes and yes, then I don't think you need to mess with the ECU, there is something else causing the problems. If no to either of those, then maybe it would be easier to just re-install those N51 components?

yes and yes, the n51 also has different compression ratios and im wondering if that’s not what’s causing my issues.

[nrussell22]

Originally Posted by Black_Ls1

I’ve done a swap from N51 to N52. All I did was keep the intake manifold and the fuel injector and fuel rail from the N51. Didn’t have to do any DME swap or tune. The car has been running perfect for 6 months

interesting… what led you to keeping the injectors and rail? i’m assuming they’re different between n51 and n52. what about the SAP, did you keep or delete that?

[gbalthrop]

Originally Posted by nrussell22

I bought a 2008 e93 328i that had previously been engine swapped with an n52. the car is of the sulev model and originally came with the n51. the car will crank, start, and run rough for a few seconds before shutting off. the car throws no DME codes and after a compression test, has good compression. after inspecting the ecu it has the msv80.1 which means it was NOT swapped when the n52 was put in. my question is will buying an msv80 ecu with a cas module fix my issue? would it make more sense to try and have the ecu shipped off to someone who can convert it to an msv80? im open to any suggestions/diagnostic recommendations as im mechanically inclined and do have access to inpa.

As I understand your later post, the N52 was installed in a SULEV N51 E93, retaining the original DISA Intake, & Secondary Air Pump, as well as original MSV80 DME. I assume the original N51 Fuel tank & Radiator were also retained? From your description of the "Start, Run Rough, Stall" issue, I would use INPA to view Live Data of Fuel Pump Operation at Startup to Stall.

If you would like suggestions on what INPA Screen(s) to view or HOW to access, please ask. I have NEVER even seen an N51, but have INPA, ISTA & MSV80 in 3/2007 build N52K, so can suggest how to view EKPS Live Data. Rough running, followed by stall & NO DME Codes sounds MORE like a fueling issue.

It would be NICE to know WHY prior owner swapped engines, & if he ever had N52 run correctly. I also don't understand HOW the SAP is connected to an N52?? Was the Exhaust Manifold changed as well? Is the Pump connected to a checkvalve & the Exhaust/Head? Even if the Pump were NOT functional, THAT should only set a fault code & NOT cause the engine to stall. If the SAP installation was bodged, that could present stalling issues, but once again, there SHOULD be fault codes, such as O2 Sensor issues, AFAIK.

I would suggest attaching a ScreenPrint of:
1) INPA > Functional Jobs > F2 Identification; that shows the SGBD/Variant of each Module in the vehicle in the 4th column;

2) INPA > EKPS (Engine | Fuel Pump EKP...) > F6 Activation
You can use that screen to simply OBSERVE Pump function while under DME control (simply viewing LIVE Data, without selecting any function key to "Over-ride" DME Control.

If you get an error message that says the SGBD of fuel pump you selected is NOT FOUND (Gefunden), but another SGBD was found, there's a simple fix for that. Please post back with any issues.

If any questions, please ask & please let us know what you find,
George

[StradaRedlands]

Originally Posted by nrussell22

yes and yes, the n51 also has different compression ratios and im wondering if that’s not what’s causing my issues.

Yeah, I didn't realize it had different compression presumably by different pistons. That's something that would have to be taken into account for sure.

[xjph]

did you ever get this fixed? I have the same issues you listed in your first thread, my car isn't swapped however. I'm wondering if it's a ground issue in the 5v circuit or perhaps to do valvetronic end stops.