[JFidddy]

Hi,

I'm pulling my hair out now with my 05 325i Touring, N52 engine.

A few weeks ago I topped up the oil after a message saying it was low. After doing so, it started to run a bit rough, then eventually it started cutting out, but would start, usually cutting out after about 20-30 seconds, while the RPM was bouncing about a bit.

Now the car won't start at all and hasn't done for about a week. I've tried quite a few things now such as;

- MAF sensor unplugged
- ECC unplugged (the one on top of the engine)
- IBS disconnected
- Replaced camshaft position sensor
- Cleaned VANOS
- Cleaned oil pressure sensor
- Fully charged battery
- Tested fuses, including the 5 in the small black box in the bigger white box on the right hand side of the cowl where the DME resides.
- Pulled all the spark plugs to see if they were covered in oil (they weren't)
- Sync'd CAS/EWS using INPA/Tool32
- Re-registered battery (if got quite low at one point and I thought it might be an anti-tamper issue)

I've got INPA, ISTA etc. The only code I'm getting now is 2E77 which is:
"DME: Firing, voltage supply"

I'm running out of things to try now? Any suggestions?

[ptpending]

try to check or swap coils
also you can check what is condition of the ground strap between engine and car body

[JFidddy]

Originally Posted by ptpending

try to check or swap coils
also you can check what is condition of the ground strap between engine and car body

Ok, I'll swap some coils, but I'd expect codes for individual coils if some were failing, but the code I'm getting is for lack of power to all six?

If you mean the strap that connects to the body near the washer fluid tube, I've checked that, it's solid. I can remove it and clean both ends though?

My thoughts are possibly the connector thing on the positive of the battery in the boot? Or that the DME itself is the problem - I've seen some people say they get submerged in water as a pool of water collects in the relay box, but I couldn't see any water in mine.

[JFidddy]

At this point I'm contemplating scraping the car, as this is doing my head in.

I've checked the 12v at the ignition coil connectors, and they're all fine, so therefore it must be grounds, but both grounds are firmly connected to the valve cover, the ground between the engine and the body is solid and I've cleaned both ends...

Therefore, I don't see how I can still have this 2E77 error as I've ruled out all the things it says, voltage to coils and grounding as per:

https://www.bmwfault.codes/XMLDiagVi...IANQA1ADAANAA=

"Check voltage supply and ignition wiring loom including interfaces Inspect and clean the ground cable in the engine compartment (ground connection in the E-Box and secondary grounds, including the one from the ignition coil bolted to the cylinder head, and the strap from the engine to the body"

Unless this code is a red herring and my issue is actually that the DME is damaged? Everything else on the car works as it should, it just won't fire. It's probably worth about £2500 and I'm not sure I wanna pump money into it with a mechanic to not get a fix.

[JFidddy]

gbalthrop I've seen you answer loads of questions from my searches about electronics and wiring - are you able to assist? The diagrams you've provided in other threads have been incredibly useful, but some links are dead since newtis was taken down.

[NZE90]

Have you checked the main earth strap under the car? It's on the LH (UK passenger side) of the engine in the area of the engine mount.

[JFidddy]

Originally Posted by NZE90

Have you checked the main earth strap under the car? It's on the LH (UK passenger side) of the engine in the area of the engine mount.

The one that splits out from the e-box and attaches near/lower down the strut tower on the passenger side and is a little bit awkward to get to? The black cable with red ends? (rather than the woven strap on the other side)

If so, I've not had it fully off, but have given is a wriggle, it's on tight.

Is there another one hidden under the engine or lower down?

If it was a bad ground I'd expect my issue to be intermittent, whereas it won't start any time at the moment. Also, there are a few grounds aren't there, so wouldn't another one take the load?

[NZE90]

No there is another large braided earth strap that bolts onto the engine mount bracket and the chassis rail. This is the main earth, so very important. Lh side of engine. It's very common for them to corrode and fail, especially if you live in the UK. And no, it will cause permanent issues if it's badly corroded or broken, and as this is the MAIN earth we ate talking about, the other earths will definitely not take the load.

It is a bit hard to see from the top but not impossible. Easier from underneath. These cars are very fussy with their electronics, so everything must be in good condition all there will be issues.

[JFidddy]

Originally Posted by NZE90

No there is another large braided earth strap that bolts onto the engine mount bracket and the chassis rail. This is the main earth, so very important. Lh side of engine. It's very common for them to corrode and fail, especially if you live in the UK. And no, it will cause permanent issues if it's badly corroded or broken, and as this is the MAIN earth we ate talking about, the other earths will definitely not take the load.

It is a bit hard to see from the top but not impossible. Easier from underneath. These cars are very fussy with their electronics, so everything must be in good condition all there will be issues.

Thanks for the reply. I'll get car up and take a look. I need to remove the skid pan anyway as I dropped a bolt the other day and need to retrieve it.

Can I test this by bypassing it? Can I connect a jump cable between the engine block and another ground point on the body/chassis?

[gbalthrop]

Originally Posted by JFidddy

... 05 325i Touring, N52 engine. I've got INPA, ISTA etc. The only code I'm getting now is 2E77 which is: "DME: Firing, voltage supply"...

Here is BMW Fault Code Lookup Definition, and Fault Info Link for 2E77:
2E77 | DME: Firing, voltage supply | msv70 | Engine electronics | View
https://bmwfault.codes/XMLDiagView?d...IANQA1ADAANAA=

See "Service Notes" in Fault Info for Diagnostic Testing Steps. If any questions about wiring or connectors, please furnish Last-7 Characters of your VIN, and we can provide ISTA Wiring Diagrams, component locations, connector views, etc.

Does INPA or ISTA show RPM signal in 180 to 200 Range during Starter Cranking (DME Live Data)? Do you have a cheap Spark Checker?
https://www.amazon.co.uk/Sealey-SEAQ...s%2C152&sr=8-4

George

[JFidddy]

Originally Posted by gbalthrop

Here is BMW Fault Code Lookup Definition, and Fault Info Link for 2E77:
2E77 | DME: Firing, voltage supply | msv70 | Engine electronics | View
https://bmwfault.codes/XMLDiagView?d...IANQA1ADAANAA=

See "Service Notes" in Fault Info for Diagnostic Testing Steps. If any questions about wiring or connectors, please furnish Last-7 Characters of your VIN, and we can provide ISTA Wiring Diagrams, component locations, connector views, etc.

Does INPA or ISTA show RPM signal in 180 to 200 Range during Starter Cranking (DME Live Data)? Do you have a cheap Spark Checker?
https://www.amazon.co.uk/Sealey-SEAQ...s%2C152&sr=8-4

George

Hi George,

Thanks for that. I've got ISTA and INPA, not sure how to show RPM signal though?

I used ISTA again today and created a test plan, where is suggested steps - for 2E77 it says to check the 30A fuse, which I've done, and check the three different wires that go into each coil, the orange, brown and white.

I know the orange is live, and brown is ground, what does the white do? I've tested the live/orange, how can I test the ground and the white?

Also, is the circuit one where if a single ground to one coil had failed, all six would cease to work, because the circuit is broken?

I had an AA guy out today to look at it, and he said the fuel pump is priming, and then it cuts out because the fuel pump isn't getting signal from the engine that it's started/running? That's what he gleamed from the 2E77 fault code anyway.

[spw]

Hi JFidddy, have you sorted out your problem with 2E77? Did you replaced the ECU?
I have the same problem with my e63 630i