N54 won't start after rebuild. DSC, DBC, and Fuel pump errors.

oilcrankinject · 07-02-2020, 07:15 PM

I have been asking on the FB groups but I am here...

Engine had rod knock so I rebuilt it. Engine cranks but will not start.

So far: New battery, new starter, and cleaned up engine ground, that allowed my motor to crank.

That is it. I pulled my plugs and they are dry. My BT cable cannot read engine codes - cannot connect to module and INPA has a script error whenever I try to enter in injector values.

When I turn on my ignition, the low pressure fuel pump comes on and stays on until I turn the car off. BT shows a CED4 - Cannot connect to engine module error.

I also have a DSC and DBC errors. All of this relates to either the DME (MSD81) or CAS (Car access system).

Can anyone help me? I just want to drive my car again.

feuer · 07-02-2020, 07:22 PM

Did you rebuilt the engine yourself and what else you have done to diagnose the issue other than scanning for fault codes and checking the spark plugs?

oilcrankinject · 07-02-2020, 09:03 PM

You have no idea.

I rebuilt the engine myself. It turns over, just wont start.

Verified DME wiring (3x)
Checked main grounds (all good)
Checked the voltage on the coils and injectors (battery voltage on 2/3 points on coils, 3rd is ground, and box points on injectors.
Checked at least 20 different fuses.
Spent hours and hours on newtis.info looking for wiring diagrams.

I think my faults are all related but I do now how. My DME is supply power to coils and injectors but I cannot connect to it read codes or change stuff with INPA.

Nismo G · 07-02-2020, 10:04 PM

1. Assuming you checked fuses?

2. Negative cable coming off the battery is known to corrode pretty bad, but underneath the battery, I believe. Even if the terminal on top looks healthy, I'd yank the battery and just check for corrosion.

3. Are you able to confirm there is spark? I'd pull a plug, put it into the removed coil, and then try starting the engine. If you have no spark then you could at least start eliminating possibilities.

Not too long ago, I read about another forum member who had a similar issue and it ended up being the timing was out 180 degrees.

oilcrankinject · 09-21-2020, 06:29 PM

Update 1:

Since my last post, car would crank but would not start them bam, locked up. Shop wanted $9k for a new engine. I pulled the engine and discovered timing had slipped. 12 bent exhaust valves. I picked up a used but good head and installed it with new friction discs (3) torque to 100nm plus 360 degrees.

Again, engine cranks but wont start.

Same error persists. I have found a half dozen related threads with no resolutions.

I installed a used DME, same errors.

07-02-2020, 07:15 PM	#1
oilcrankinject Captain 79 Rep 996 Posts Drives: nothing Join Date: Jul 2007 Location: USA iTrader: (0)	N54 won't start after rebuild. DSC, DBC, and Fuel pump errors. I have been asking on the FB groups but I am here... Engine had rod knock so I rebuilt it. Engine cranks but will not start. So far: New battery, new starter, and cleaned up engine ground, that allowed my motor to crank. That is it. I pulled my plugs and they are dry. My BT cable cannot read engine codes - cannot connect to module and INPA has a script error whenever I try to enter in injector values. When I turn on my ignition, the low pressure fuel pump comes on and stays on until I turn the car off. BT shows a CED4 - Cannot connect to engine module error. I also have a DSC and DBC errors. All of this relates to either the DME (MSD81) or CAS (Car access system). Can anyone help me? I just want to drive my car again. Last edited by oilcrankinject; 09-21-2020 at 06:30 PM..
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07-02-2020, 07:22 PM	#2
feuer Major General 4276 Rep 9,206 Posts Drives: wife crazy! Join Date: Apr 2015 Location: Chicago, IL iTrader: (5)	Did you rebuilt the engine yourself and what else you have done to diagnose the issue other than scanning for fault codes and checking the spark plugs?
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07-02-2020, 09:03 PM	#3
oilcrankinject Captain 79 Rep 996 Posts Drives: nothing Join Date: Jul 2007 Location: USA iTrader: (0)	You have no idea. I rebuilt the engine myself. It turns over, just wont start. Verified DME wiring (3x) Checked main grounds (all good) Checked the voltage on the coils and injectors (battery voltage on 2/3 points on coils, 3rd is ground, and box points on injectors. Checked at least 20 different fuses. Spent hours and hours on newtis.info looking for wiring diagrams. I think my faults are all related but I do now how. My DME is supply power to coils and injectors but I cannot connect to it read codes or change stuff with INPA.
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07-02-2020, 10:04 PM	#4
Nismo G Second Lieutenant 50 Rep 243 Posts Drives: 2008 335xi Sedan Join Date: Jul 2014 Location: Sarasota, FL iTrader: (1)	1. Assuming you checked fuses? 2. Negative cable coming off the battery is known to corrode pretty bad, but underneath the battery, I believe. Even if the terminal on top looks healthy, I'd yank the battery and just check for corrosion. 3. Are you able to confirm there is spark? I'd pull a plug, put it into the removed coil, and then try starting the engine. If you have no spark then you could at least start eliminating possibilities. Not too long ago, I read about another forum member who had a similar issue and it ended up being the timing was out 180 degrees. __________________ Current: 08 335xi Sedan - ST Suspension Coilovers - M3 Front Strut Brace - COBB Stage 1 - ECS Tuning Chargepipe + BOV - aFe Stage 2 Intake - Precision Raceworks Ignition Coils
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09-21-2020, 06:29 PM	#5
oilcrankinject Captain 79 Rep 996 Posts Drives: nothing Join Date: Jul 2007 Location: USA iTrader: (0)	Update 1: Since my last post, car would crank but would not start them bam, locked up. Shop wanted $9k for a new engine. I pulled the engine and discovered timing had slipped. 12 bent exhaust valves. I picked up a used but good head and installed it with new friction discs (3) torque to 100nm plus 360 degrees. Again, engine cranks but wont start. Same error persists. I have found a half dozen related threads with no resolutions. I installed a used DME, same errors.
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