Bad DME?

[genesis]

Started last year w misfires, DME/EWS was sent out and repaired( told old coil failed and shorted DME?). Coils, plugs replaced after getting DME back. 2 days later car shuts off completely while driving, no sputtering just dead. Sent back, retested, told was good. Car ran for 2 months until SMG pump left the chat. Car sat 4 months, Started car weekly, eventualky started seeing misfire codes on 2, then 3 cyl but idled ok. Replaced SMG pump, car still undrivable. Sent DME out to retest (now past warranty) told ignition drivers are within spec and no other apparent issues. They couldnt confirm 100% since they dont have a test car, told me issue is w car. Bought a complete used harness for $150 and swapped, same thing, no spark/not firing cyl 4,5,6

Need to rule out any other possibles before I drop more money into this German black hole

[Slideways]

Started last year w misfires, DME/EWS was sent out and repaired( told old coil failed and shorted DME?). Coils, plugs replaced after getting DME back. 2 days later car shuts off completely while driving, no sputtering just dead. Sent back, retested, told was good. Car ran for 2 months until SMG pump left the chat. Car sat 4 months, Started car weekly, eventualky started seeing misfire codes on 2, then 3 cyl but idled ok. Replaced SMG pump, car still undrivable. Sent DME out to retest (now past warranty) told ignition drivers are within spec and no other apparent issues. They couldnt confirm 100% since they dont have a test car, told me issue is w car. Bought a complete used harness for $150 and swapped, same thing, no spark/not firing cyl 4,5,6

Need to rule out any other possibles before I drop more money into this German black hole

Borrow a DME (code out EWS) from another car to rule out the DME. Are there any other codes?

[genesis]

Don’t have access to another DME unless I buy one and have it coded

[sapote]

1. Car ran for 2 months until SMG pump left the chat. Car sat 4 months, Started car weekly, eventualky started seeing misfire codes on 2, then 3 cyl but idled ok. Replaced SMG pump, car still undrivable.

2. same thing, no spark/not firing cyl 4,5,6

1. I'm confused. How did you start the engine weekly while having a bad SMG pump?
2. I didn't see that you wrote it had misfire on 4,5,6 before. So maybe bank2 ignition coils lost 12v supply and not related to DME. Verify the connectors have 12v supply.

[gheorghe]

Don’t have access to another DME unless I buy one and have it coded

Let me know if you need a DME and EWS. I have a matching set off an '06

[bigjae46]

You can try resistance testing the coil harness with it connected to the DME to ground. There are 3 leads. Each position should have the same resistance across the 6 coil plugs. If there is one that is different, then unplug the ECU. Resistance test end to end for each wire - you'll get a different number since you're only testing the resistance of the wire. If there are no differences between the wires the its the ECU.

I had a persistent cyl 6 misfire..took 3 months but finally tracked it down.

My theory is I had a bad coil, kept driving it and it f'd a MOSFET on the ECU. The coils are all wired together...IIRC...the ground is in series and the other 2 leads are in parallel. So if I coil goes bad, you get a different final resistance at the ECU with cause sensitive electrical components to fail. Like a MOSFET.

[genesis]

1. I'm confused. How did you start the engine weekly while having a bad SMG pump?
2. I didn't see that you wrote it had misfire on 4,5,6 before. So maybe bank2 ignition coils lost 12v supply and not related to DME. Verify the connectors have 12v supply.

Gearbox was stuck in neutral and would start, just would not go into gear.

At that time, the car was actually throwing misfire codes on cyl 3 and 4, then 3,4,5 without cylinder shutdown. After a few weeks the idle began surging up and down a few minutes after startup, there were clicking noises under the hood, and another odd sound coming from the front, where the Vanos pump disk is located.

[sapote]

1. Gearbox was stuck in neutral and would start, just would not go into gear.

2. At that time, the car was actually throwing misfire codes on cyl 3 and 4, then 3,4,5 without cylinder shutdown. After a few weeks the idle began surging up and down a few minutes after startup, there were clicking noises under the hood, and another odd sound coming from the front, where the Vanos pump disk is located.

1. I believe you wrote the smg pump was bad. If pump was bad, low oil pressure, then this would disable the starter to crank.
2. I would check the 12v bus supply on the coil harness with key turned on.

[genesis]

1. I believe you wrote the smg pump was bad. If pump was bad, low oil pressure, then this would disable the starter to crank.
2. I would check the 12v bus supply on the coil harness with key turned on.

I think it may have been just the electric motor that was on its way out but since I don’t do the work myself, I bit the bullet and replaced w a complete MLR pump w salmon relay and fuse rather than lay 2X the labor. Shifts fine now.

Where would you check for 12V? I’m assuming shop checked it, but at this point I want to be sure everything else can be ruled out. Appreciate the help

[sapote]

Where would you check for 12V?

The coil connector has 3 pins and one of them is the 12v supply.

[genesis]

The coil connector has 3 pins and one of them is the 12v supply.

So that would be on the harness that runs from coils to the DME? And do the injectors draw power directly from DME?

[sapote]

So that would be on the harness that runs from coils to the DME? And do the injectors draw power directly from DME?

It's the Red/White wire of the harness, and it's connected to F1 of the 5-fuse pack near DME. DME running software and turns on the main relay which supply 12v to these fuses.

[genesis]

Ok, got it. So yes, they did check voltage on the harness, and also on the replacement harness we swapped it. Same on both.

thank you sapote-greatly appreciated