[Lucas_335i]

Background Info:
122k Miles, MSD80 DME, Index 1 injectors.
Purchased car 15 days ago, and drove in limp mode for 20 miles, lots of mis-firings.
Filled tank and added can of seafoam to tank.
Next 2 mornings, ran well for about an hour.
4th day, died in traffic, very hot day. Never restarted. Just cranks.
Car seems OEM, but not well cared for. Valve cover and front main seal leaks present.

Other unrelated items:
When in park, and ac fan at full blast, if I tapped the accelerator, the ac fan would stop for 3 seconds.
Also noticed same fan blip sometimes when driving.

Car towed home, connected battery charger to jump point under hood.

Read the following codes. Used ISTA D DME history.
2E35 Injection valve cyl 6, open circuit
2E34 Injection valve cyl 5, open circuit
30BA DME Internal Failure
30BB DME Internal Failure
2ACC DME Main Relay switch delay.
Not sure how old the first 4 errors are, but only the 2ACC code is present now.

With this information I sent the DME to Circuit Board Medics in SC. They responded with the DME tested well, no action was taken.
( I am not sure what and how they tested. I have used this service before and they are very reliable.)

Got DME back, only fault is 2ACC, DME Master relay. Located wiring diagram using newtis, for a 2007/4 through 2007/8 335i.
K6300 Main DME relay is located inside the fuse panel. Opened fuse panel and tested K6300 relays, with 12 v and measuring open and closed resistances of its 2 contacts.
I no longer suspected the k6300 or the fuse panel. Checked all fuses. Not all the wire colors matched the TIS drawings. That is puzzling.
Noticed some heat damage on the connection of the B+ cable to the back of the relay panel. Purchased a new relay panel, and changed it.
Also noticed that the B+ cable recall had been performed.in the past.

Checked F50 12 v to DME.
K6300 closes and puts 12 volts to F74,75,76,77,78 and 79. All get 12 volts.

Additional troubleshooting and actions performed:

Replaced crankshaft position sensor with OEM sensor.

When I spray carb cleaner into the air intake, car runs for about 5 sec.
There is some fuel pressure at the fuel rails. Did not measure it. Just opened fitting a little and it sprayed out.

Changed to new Delphi coils and new Bosch plugs ( did not gap plugs)

Old plugs and coils were drenched in oil. Old Plugs 2345 were wet with fuel.

Replaced valve cover gasket.

Spent last 3 evening reading lots of forums and facebook groups. So here are my plans:

1 Check verify engine block ground straps.
2 Use IMPA or ISTAD to check the fuel pressures being measured. Not sure if both pressures are read by DME
3 If pressure within spec? then pull out all injectors into bottles and see if firing or leaking.
4 If not put, scope on injector wires and see if we get electrical signal to the injectors.
5 Find and clean both MAF sensors.
6 Got some notes from e90posts forum on how to use IMPA and inspect all the required signals are present for starting. Learning curve here.
7 Need to figure out how the DME determines the K6300 relay fault. All wiring and function of the relay were verified.

This is were I am right now. Any direction and advice is appreciated.
I have some experience with BMWs. I presently own an 07 X3, an 08 M5 e60, 08 M6 e64, and now for my wife an e93 …. This is my first dealing with the N54 platform.

Thanks In advance.

[Lucas_335i]

Update. Removed and cleaned, brushed all surfaces for the ground strap to the motor. Still no start. This kinda makes sense. If the ground was missing to the engine block, the starter circuit would not work.

[Lucas_335i]

Update #2. As per some forum suggection, I also attempted to disconnect the IBS connector from the negative pole of the battery. Still no effect.

I also tryed using a battery jumper cable to put a better ground to the engine from the body. No change. I believe the ground strap is sound.

[Lucas_335i]

I used IMPA last night to measure the HPFP. Upon a crank attempt, I am getting about 167772 hPa, about 2400 psi. Is this an appropriate pressure?
Also noted that the low pressure fuel pump reading is not moving, at 3839 hPa about 55psi. But it is frozen signal. Anyone seen this before. I guess i be removing back seats tonight....

[iqraceworks]

Sounds like your whole problem might be the LPFP. It should attempt to prime at full power as soon as you open the door and get in the car. You should be seeing around 72psi when the car is idling. Could be an issue with the LPFP pressure sensor also.

Seems like that thing has a ton of issues....hope you got it for dirt cheap.

[dpaul]

You have 2400psi rail pressure so neither fuel pump is the problem. This a very likely a DME problem (not a DME relay problem), there are plenty of threads describing it.

You're probably going to have to replace the DME. However, the SK/ISN in the DME must match the one encoded in the CAS and BMW standard tools will not give you access to the SK/ISN in either module.

So either buy a used DME, CAS and key from the same car as a set or get a used DME and send it along with your CAS and key to someone with the skills/equipment to read the SK from the used DME and write it to the CAS.

That said, one thing you may not have checked is the state of the pins on the DME connectors. It's suprizingly easy to get one bent over or pushed inward to the point where contact fails.

Finally, FWIW the BMW standard tool you are referring to is INPA, not IMPA

[Lucas_335i]

Dpaul, thanks for the information. Also sorry for the incorrect spelling. Old age is getting to me. I have been looking at pressure data others have posted, and I can see the priming of the HPFP goes to 2400 psi and then goes down to 700/800 when injectors are firing. I am concerned that my injectors are not firing or not being told to fire while cranking. I hate to say this but the DME may no be sending injector commands. Thanks for your assistance.

[N54zoegottii]

Was there any fix for this post