HELP: Engine Replacement Assistance Needed.

mokk76 · 06-29-2016, 10:47 AM

HELP, I have a 2011 550i Sport that got flooded out and the engine needed to be replaced. So the engine was replaced with a 4.4L Twin Turbo engine off a 2010 750i. The problem now is that engine wire harness transmission connector that came with that engine does not fit into my existing transmission. So I got a complete engine wire harness for a 2011 550i that fits the transmission, but it does not fit the engine (there are several loose/missing connectors). My car has an 8 speed tranny while the 750i has a 6 speed tranny I believe. What am I missing? Or will that engine not work for me? Please any help/suggestions will be appreciated. Thank you

PJinCA · 06-29-2016, 10:55 AM

Sounds like the engine is fine, the transmission is another story. You can't replace an 8 speed trans with a 6 speed one (ZF 8HP for a ZF 6HP) and expect the wires to line up. They are completely different. Can it work? Yes, but it is not going to be "plug an play", our cars always had the 8HP - 8 speed trans, so it will need to be modified to accept a different trans.

mokk76 · 06-29-2016, 11:02 AM

Quote:

Originally Posted by PJinCA

Sounds like the engine is fine, the transmission is another story. You can't replace an 8 speed trans with a 6 speed one (ZF 8HP for a ZF 6HP) and expect the wires to line up. They are completely different. Can it work? Yes, but it is not going to be "plug an play", our cars always had the 8HP - 8 speed trans, so it will need to be modified to accept a different trans.

Correct, you're exactly right, so my question is do i have to some how hotwire the transmission connector from the 8 speed trans to the wire harness of the 750i engine? Or use the harness off the 550i that has the right connector and try to fit it to the 750i engine somehow? Thanks.

PJinCA · 06-29-2016, 11:20 AM

It's more than just getting it connected, the car's ECU will need to be modified as well. You will need a custom tune to make the ECU accept a trans it wasn't designed for. It might be easier to sell the trans you have (the 6 speed), then go and buy an 8HP70 that your 550 originally came with. Less hassle, the connectors will fit, and no customm coding will be necessary.

mokk76 · 06-29-2016, 12:25 PM

Quote:

Originally Posted by PJinCA

It's more than just getting it connected, the car's ECU will need to be modified as well. You will need a custom tune to make the ECU accept a trans it wasn't designed for. It might be easier to sell the trans you have (the 6 speed), then go and buy an 8HP70 that your 550 originally came with. Less hassle, the connectors will fit, and no customm coding will be necessary.

The transmission I have is the original 8 speed transmission, I am only changing out the engine, but the transmission connector on the wire harness off the 2010 750i engine is for the 6 Speed and does not physically fit on mine which is a 2011 550i 8 Speed transmission.

PJinCA · 06-29-2016, 01:03 PM

Quote:

Originally Posted by mokk76

The transmission I have is the original 8 speed transmission, I am only changing out the engine, but the transmission connector on the wire harness off the 2010 750i engine is for the 6 Speed and does not physically fit on mine which is a 2011 550i 8 Speed transmission.

Ok, gotcha. In that case, yes, an F10 550 wiring harness should work then. The new engine and trans combo will probably need to be coded to your car to work properly though, but still, that is less expense than custom coding.

ezaircon4jc · 06-29-2016, 08:02 PM

Quote:

Originally Posted by PJinCA

Ok, gotcha. In that case, yes, an F10 550 wiring harness should work then. The new engine and trans combo will probably need to be coded to your car to work properly though, but still, that is less expense than custom coding.

Wouldn't the harness have a problem on the engine side?

PJinCA · 06-29-2016, 08:11 PM

Quote:

Originally Posted by ezaircon4jc

Wouldn't the harness have a problem on the engine side?

Both the engine and trans will have to be coded to the car, since they are both VIN specific parts (like nearly everything on our cars).

Stück · 06-29-2016, 08:11 PM

Quote:

Originally Posted by mokk76

HELP, I have a 2011 550i Sport that got flooded out and the engine needed to be replaced. So the engine was replaced with a 4.4L Twin Turbo engine off a 2010 750i. The problem now is that engine wire harness transmission connector that came with that engine does not fit into my existing transmission. So I got a complete engine wire harness for a 2011 550i that fits the transmission, but it does not fit the engine (there are several loose/missing connectors). My car has an 8 speed tranny while the 750i has a 6 speed tranny I believe. What am I missing? Or will that engine not work for me? Please any help/suggestions will be appreciated. Thank you

You should go to Lonestar again and try to find another harness

Sorry, I feel for you man. Really I still think the best course of action is to bite the bullet and order the correct harness at the dealer by the VIN.

mokk76 · 06-29-2016, 09:32 PM

Quote:

Originally Posted by Stück

You should go to Lonestar again and try to find another harness

Sorry, I feel for you man. Really I still think the best course of action is to bite the bullet and order the correct harness at the dealer by the VIN.

Thanks Buddy, that is exactly what I have done. So now i have 2 harnesses, one for my original car (2011 550i) and another for the engine (2010 750i), hopefully between the 2 we'll get it to fit. Just trying to figure out if i'll need to change any parts or sensors on the engine (2010 750i) to make the original (2011 550i) harness fit. Thank you.

mokk76 · 07-11-2016, 10:53 PM

UPDATE: OK, so i have the right harness all connected up now, but the transmission is stuck in Neutral and it is just flashing "N". It is not moving into park "P". What could be wrong? OrlandoBimmer Any ideas? Thank you....

Stück · 07-11-2016, 11:34 PM

I'm not sure if your model transmission has the screw on the side of the case that mechanically forces a lever into N or not, but I've had this happen before and what you're describing sounds right.

mokk76 · 07-12-2016, 12:27 AM

Quote:

Originally Posted by Stück

I'm not sure if your model transmission has the screw on the side of the case that mechanically forces a lever into N or not, but I've had this happen before and what you're describing sounds right.

Yes, my transmission does have that screw on the side of it and we actually screwed it upwards to unlock the transmission to move the car. Does that permanently keep the transmission in "N"? I will try releasing that screw back down and see if that does the trick. Thank you.

Stück · 07-12-2016, 08:09 AM

Yeah, that is the point of that screw/lever to force the transmission into Neutral for towing purposes. I bet that is your problem. Hope it is!

mokk76 · 08-26-2016, 10:00 PM

Finally got the car to start and drive, but I have a couple of errors that remain. I am getting a Drivetrain Malfunction error and a DSC Malfunction. Does the engine computer need to be reprogrammed to recognize the new engine? Or what else needs to be done? Thank you.

06-29-2016, 10:47 AM	#1
mokk76 Enlisted Member 12 Rep 32 Posts Drives: 2005 BMW 545i Join Date: Jun 2016 Location: Houston, TX iTrader: (0)	HELP: Engine Replacement Assistance Needed. HELP, I have a 2011 550i Sport that got flooded out and the engine needed to be replaced. So the engine was replaced with a 4.4L Twin Turbo engine off a 2010 750i. The problem now is that engine wire harness transmission connector that came with that engine does not fit into my existing transmission. So I got a complete engine wire harness for a 2011 550i that fits the transmission, but it does not fit the engine (there are several loose/missing connectors). My car has an 8 speed tranny while the 750i has a 6 speed tranny I believe. What am I missing? Or will that engine not work for me? Please any help/suggestions will be appreciated. Thank you
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06-29-2016, 10:55 AM	#2
PJinCA USAF Pararescue Veteran 332 Rep 770 Posts Drives: F10 535 Join Date: Feb 2013 Location: SoCal iTrader: (0)	Sounds like the engine is fine, the transmission is another story. You can't replace an 8 speed trans with a 6 speed one (ZF 8HP for a ZF 6HP) and expect the wires to line up. They are completely different. Can it work? Yes, but it is not going to be "plug an play", our cars always had the 8HP - 8 speed trans, so it will need to be modified to accept a different trans.
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06-29-2016, 11:20 AM	#4
PJinCA USAF Pararescue Veteran 332 Rep 770 Posts Drives: F10 535 Join Date: Feb 2013 Location: SoCal iTrader: (0)	It's more than just getting it connected, the car's ECU will need to be modified as well. You will need a custom tune to make the ECU accept a trans it wasn't designed for. It might be easier to sell the trans you have (the 6 speed), then go and buy an 8HP70 that your 550 originally came with. Less hassle, the connectors will fit, and no customm coding will be necessary.
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07-11-2016, 10:53 PM	#11
mokk76 Enlisted Member 12 Rep 32 Posts Drives: 2005 BMW 545i Join Date: Jun 2016 Location: Houston, TX iTrader: (0)	UPDATE: OK, so i have the right harness all connected up now, but the transmission is stuck in Neutral and it is just flashing "N". It is not moving into park "P". What could be wrong? OrlandoBimmer Any ideas? Thank you....
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07-11-2016, 11:34 PM	#12
Stück Major 801 Rep 1,214 Posts Drives: F15 X5, E46 330i, R56 Mini.S Join Date: May 2016 Location: Houston, TX iTrader: (4)	I'm not sure if your model transmission has the screw on the side of the case that mechanically forces a lever into N or not, but I've had this happen before and what you're describing sounds right. Last edited by Stück; 07-12-2016 at 09:36 AM..
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07-12-2016, 08:09 AM	#14
Stück Major 801 Rep 1,214 Posts Drives: F15 X5, E46 330i, R56 Mini.S Join Date: May 2016 Location: Houston, TX iTrader: (4)	Yeah, that is the point of that screw/lever to force the transmission into Neutral for towing purposes. I bet that is your problem. Hope it is!
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08-26-2016, 10:00 PM	#15
mokk76 Enlisted Member 12 Rep 32 Posts Drives: 2005 BMW 545i Join Date: Jun 2016 Location: Houston, TX iTrader: (0)	Finally got the car to start and drive, but I have a couple of errors that remain. I am getting a Drivetrain Malfunction error and a DSC Malfunction. Does the engine computer need to be reprogrammed to recognize the new engine? Or what else needs to be done? Thank you.
	Appreciate 0 Quote