[drawz]

Cross posting this to hopefully get some more attention on the matter:

I'm getting a 2E31 "DME Fuel Injector Cylinder 2 Activation" code with rough running and loss of power (feels like misfiring, but don't have a code for that per se) on my 2006 330xi (N52 3-stage) with 86k miles. Initially noticed after merging on the highway with no CEL, but now occurs on cold start with a CEL. There's a fuel smell that seems to be coming from the exhaust.

It seems that N52 injector failure is fairly rare and these things are pretty expensive for new injectors ($180-200 for Genuine, $140 for VDO OEM). Remanufactured ones are much less, only $35-45, but don't seem to be too reliable based on the reviews. I also see there are o-rings and a clip that should be replaced at the same time.

Seems that it's ok to replace just 1, but I see some advocating to replace all 6. Any thoughts on that? Anything else to check before replacing the injector(s)?

Link to my original post (same content): https://www.e90post.com/forums/showthread.php?t=1822879

[e90yyc]

Sorry—I don’t know about the specifics of what else you should replace, but given how rarely these fail I don’t think it makes sense to replace the other 5 if they’re still good. Can’t see why this would be necessary. If it was likely the other 5 were close behind then maybe, but that shouldn’t be the case.

[drawz]

That's what I'm leaning toward at this point. One new OEM VDO seems reasonable. I did find a few comments about bad wiring and flaky electrical connectors.

[drawz]

Ordered a refurb injector (GB reman) from FCP Euro because I don't think they'd sell it if it was terrible...but forgot a new set of o-rings for the other injectors. In the meantime, I ran the ISTA fuel injector activation test on both a warm and cold car (engine off) and I can hear it actuating just fine. This test is also available through the Foxwell NT510. Code and symptoms went away after this, so maybe it's just sticking intermittently? Still going to replace it.

PS - FCP says in their Q&A section that it's ok to replace just one.

[gbalthrop]

Here are the BMW Fault Code Lookup Definition for 2E31, and the Fault Information Sheet link (which says "Cylinder 2 Injector 'A' Circuit High"), suggesting check wiring (and connector) FIRST:
2E31 | DME: Fuel injector, cylinder 2, activation | msv70
https://bmwfault.codes/XMLDiagView?d...YAMgAyADAANAA=

BTW, Bentley has this definition for 2E31:
P0202 | 2E31 | Injector Circuit/Open - Cylinder 2

"Circuit High" can mean High Resistance (open circuit is infinite resistance, so that's pretty high ;-). You have an intermittent issue as indicated by your ISTA tests. That's more likely a wiring or connector fault than a mechanical fault with the injector itself.

I would try simply removing the Two-Pin Connector from Injector #2 and cleaning the pins & sockets with Electronic Contact Cleaner, and inspecting the wiring and connector for any damage, particularly the White/Green (Activation) wire. If you get a chance to fully-diagnose the situation, I'd be interested in knowing what the Freeze Frame Data for the 2E31 Code indicates as far as RPM and such when the Fault Code was saved. INPA will give MORE Fault Detail than ISTA (INPA > DME > F4 > F1 > F3 Read Fault Memory with FF Data), but you have to translate the German with Google Translate:
https://translate.google.com/?sl=de&tl=en&op=translate

Please let us know what you find,
George

[nsjames]

check the wiring.

when i bought my car the dealer had replaced the #1 injector for the same reasons.
misfire persisted randomly.
it was the plug not making consistent contact with the pin on the injector.
some light tensioning with a pick and it's never been back for over 60K miles.

[drawz]

Originally Posted by gbalthrop

Here are the BMW Fault Code Lookup Definition for 2E31, and the Fault Information Sheet link (which says "Cylinder 2 Injector 'A' Circuit High"), suggesting check wiring (and connector) FIRST:
2E31 | DME: Fuel injector, cylinder 2, activation | msv70
https://bmwfault.codes/XMLDiagView?d...YAMgAyADAANAA=

BTW, Bentley has this definition for 2E31:
P0202 | 2E31 | Injector Circuit/Open - Cylinder 2

"Circuit High" can mean High Resistance (open circuit is infinite resistance, so that's pretty high ;-). You have an intermittent issue as indicated by your ISTA tests. That's more likely a wiring or connector fault than a mechanical fault with the injector itself.

I would try simply removing the Two-Pin Connector from Injector #2 and cleaning the pins & sockets with Electronic Contact Cleaner, and inspecting the wiring and connector for any damage, particularly the White/Green (Activation) wire. If you get a chance to fully-diagnose the situation, I'd be interested in knowing what the Freeze Frame Data for the 2E31 Code indicates as far as RPM and such when the Fault Code was saved. INPA will give MORE Fault Detail than ISTA (INPA > DME > F4 > F1 > F3 Read Fault Memory with FF Data), but you have to translate the German with Google Translate:
https://translate.google.com/?sl=de&tl=en&op=translate

Please let us know what you find,
George

You're absolutely right. I went through the ISTA service plan and it wanted me to measure the resistance across the two injector pins, with the correct range being 8.7-17.5 ohms. I believe this came after the activation test where you listen for audible clicking. Now that I have a replacement injector in hand, I'm ready to take things apart and will perform this test first. I have the ISTA fault history (see below), but didn't try to get it from INPA. May try that before I start as well.

Originally Posted by nsjames

check the wiring.

when i bought my car the dealer had replaced the #1 injector for the same reasons.
misfire persisted randomly.
it was the plug not making consistent contact with the pin on the injector.
some light tensioning with a pick and it's never been back for over 60K miles.

I'm trying to visualize exactly how to do this. Which direction to you tension it? To one side? Which side? Maybe doesn't matter. Or pull it out slightly? I assume this is on the injector side, not the harness side? If so, breaking it would be less of a big deal than breaking the harness. It would be great if this were the fix.

[nsjames]

take the injector connector off and look into where the pins go.
make that gap in the terminals smaller with a pick from the front. They're basically spade terminals. It will become obvious what you need to do to make them fit tighter when you take it apart. done at the connector, there's nothing to do at the injector side, it just has pins sticking out from molded plastic.

Should you technically replace the pins in the connector? probably.
Does it work fine to slightly bend them from the front so they grip the injector pins tighter?
been working for me for 67K miles. Haven't touched it since.

[drawz]

Originally Posted by nsjames

take the injector connector off and look into where the pins go.
make that gap in the terminals smaller with a pick from the front. They're basically spade terminals. It will become obvious what you need to do to make them fit tighter when you take it apart. done at the connector, there's nothing to do at the injector side, it just has pins sticking out from molded plastic.

Should you technically replace the pins in the connector? probably.
Does it work fine to slightly bend them from the front so they grip the injector pins tighter?
been working for me for 67K miles. Haven't touched it since.

Thanks! I'll give that a try first.

[drawz]

Misfires and CEL disappeared for a few days, but back again yesterday and today. Took everything apart and measured the resistance on each injector. Open circuit on injector 2! The rest were around 12 ohms. So it does seem to be a bad injector with maybe an intermittently bad internal connection. Off to the dealer for some o-rings.

[nsjames]

well at least it's an easy job.

[drawz]

It's alive!

Lessons learned:
1. The BMW ISTA test plan works! Should have just followed that from the start.
2. The GB reman injector seems to work fine, but definitely felt like a used & remanufactured part. Contacts seemed a bit corroded, which initially gave me trouble measuring the resistance and I thought it was bad. Cleaned up the contacts and hit it with some contact cleaner and good to go.
3. Just pull up on the injector wiring harness to release it. Don't mess with the metal clips like some of the videos show.
4. More fuel spilled out of the rail than I expected and just kept coming after I actually pulled an injector out of it. I was expecting a fair amount, but it still caught me off guard.
5. Crank the engine with the fuel pump fuse pulled to reduce the fuel pressure. Less fuel spillage.
6. Removing the fuel supply line is not obvious if you've never done it before. I'll link a YT video that shows how.
7. I spent way too much time debating how to lube the o-rings. Was going to use Super Lube multi-purpose PTFE grease, but once I got it open, there was already oil on the o-rings, so I went with some fresh motor oil. Much debate on this topic if you google. Avoid silicone products, which can jack up your O2 sensors.
8. Final pro-tip - be sure to put the engine cover back on before putting the cowl back on! *face palm*

Also lightly bumped a valve cover bolt head, which sheared right off. Luckily it did not fall into the cylinder. Debating whether I should try to replace just that one. No leak right now. The magnesium valve cover has a different gasket than the later models that I think it might survive swapping one bolt.

Thanks for all the help!

N52 Injector DIY (but don't use silicone lube like this guy. Also just pull up on the harness and leave the metal clips alone):

Nice video showing how to depressurize the fuel rail and remove the fuel supply line. Better than the first video for these parts.

[cparke]

Originally Posted by drawz

I spent way too much time debating how to lube the o-rings. Was going to use Super Lube multi-purpose PTFE grease, but once I got it open, there was already oil on the o-rings, so I went with some fresh motor oil. Much debate on this topic if you google. Avoid silicone products, which can jack up your O2 sensors.

N52 Injector DIY (but don't use silicone lube like this guy.

About to do the re-installation myself now, and I have been analyzing exactly that same debate about lubricant to use. Some really reputable people seem to absurdly recommend using silicone products for this job, but I agree with you that it's a really bad idea.

In my case, I had sent out my injectors out to be tested and reconditioned following an episode of cold start misfiring with a fuel injector activation error code thrown (which then went away once the engine warmed up). The company that tested the injectors and ultrasonic cleaned them sold me "Super Lube Synthetic Grease with PTFE" (p/n 82340) as the O-ring grease to use for the re-installation, and reading the technical specs on this substance, it is non-silicone which makes sense too. So just throwing that out there as my recommendation too as to the proper lubricant to use.

[cparke]

Originally Posted by drawz

I'm getting a 2E31 "DME Fuel Injector Cylinder 2 Activation" code with rough running and loss of power (feels like misfiring, but don't have a code for that per se) on my 2006 330xi (N52 3-stage) with 86k miles. Initially noticed after merging on the highway with no CEL, but now occurs on cold start with a CEL. There's a fuel smell that seems to be coming from the exhaust.

It seems that N52 injector failure is fairly rare ...

Originally Posted by e90yyc

Sorry—I don’t know about the specifics of what else you should replace, but given how rarely these fail ...

Originally Posted by nsjames

check the wiring.

when i bought my car the dealer had replaced the #1 injector for the same reasons.
misfire persisted randomly.
it was the plug not making consistent contact with the pin on the injector.
some light tensioning with a pick and it's never been back for over 60K miles.

Just finished dealing with this exact issue on similar car (2006 330i without turbo, standard port injection), and in my case, it clearly was something wrong with the injector itself!

Like the OP, the injector was failing intermittently at cold start after sitting outside overnight. I found that once the engine started warming up or vibrating the injector a bit, upon re-starting the car (or even just clearing the code while the engine is running) it would stop the misfiring and the injector would begin to work again temporarily.

My theory is the DME (ECU) does a basic resistance test on the injectors whenever it starts the car or when codes are cleared. Just like it does on the light bulbs. If an injector fails the test, it throws the code and disables any triggering that injector during that run cycle, causing a constant misfire but keeping the injector closed. However, this also messes up the fuel trim on the bank because now the O2 sensor thinks the engine is running lean (1/3 of the expected exhaust on the bank is missing), and it compensates on the other injectors of the bank to put out more fuel, actually causing the engine to start running rich (hence the fuel smell from the exhaust).

Anyway, I initially confirmed it was actually the injector (cylinder 3 in my case) by swapping it with cylinder 5, and then the next time it happened, lo and behold, the misfires were now on cylinder 5 instead. Replaced it with a GB Remanfactured injector and I am running good now.

Testing the resistance on the bad injector after removing it and keeping it in the box overnight, I got 45 ohms, which seems like way too high based on what I'm reading here, and should be enough to for the ECU to reject it. Then I put the injector in the refrigerator for 8 hours and re-tested it immediately and got 12 ohms resistance, which is normal from what I read here.

Those test results are a bit backwards in scenario from what I was experiencing while it was installed in the car and chillng outside overnight, but nevertheless such a major change in resistance like that from just sitting in the box or experiencing a temperature change proves in another way that the injector was internally failing. The bottom line here is before you mess too much with the injector wiring or plugs contacts, check the injector resistance itself! And be particularly mindful that temperature change and rest alone may change the readings and expose the injector itself as the failure point.

[850CSi]

Originally Posted by drawz

It's alive!

Lessons learned:
1. The BMW ISTA test plan works! Should have just followed that from the start.

I’m getting the same code on cylinder 1. How is this test run? I can’t find it in my ISTA menus. Thanks!

[gbalthrop]

Originally Posted by 850CSi

I’m getting the same code [2E31 is specific to cylinder #2 injector. There are SEVERAL possible codes related to cylinder #1 Injector. What specific Fault Code do you have?] on cylinder 1. How is this test run? I can’t find it in my ISTA menus. Thanks!

See "VI. Test Plan, Directed Diagnosis" on page 6 of attached ISTA "Fault Memory & Test Plan" pdf, for HOW to run Test Plan. You can also use "Triggering" or activations Tab (also described in pdf), to test activation of each injector ("Clock fuel injector 1" -- engine NOT running but ignition ON).

Please post the specific fault code(s) you have in DME Fault Memory. I presume this is for MSV70 DME in 2006 325i? See ISTA wiring diagram & Connector View for Cylinder #1 Injector & its 2-pin connector. That ScreenPrint is attached to NEXT post. For HOW to view documents, such as
"Fuel Injectors" SSP wiring diagram on your ISTA installation, see 2nd attached pdf.

Multimeter & Patch Cord Testing:
1) Test for 12V+ battery Voltage with Ignition ON at Orange wire at Injector Connector X6101/1 (socket #1 of connector);
2) "Tap" (DON'T hold) chassis ground to Socket #2 of Injector, to test for "Click". If injector activates, you have a wiring issue.
3) A "Noid Light" can be used to see if Ground Pulse from DME is being received at X6101/2, White wire, during cranking/running.

Please let us know what you find,
George

[gbalthrop]

Attached is ScreenPrint of ISTA Injector SSP wiring diagram, and Connector View, for MSV70 DME, 2006 325i, per prior post.
George

[850CSi]

Originally Posted by gbalthrop

See "VI. Test Plan, Directed Diagnosis" on page 6 of attached ISTA "Fault Memory & Test Plan" pdf, for HOW to run Test Plan. You can also use "Triggering" or activations Tab (also described in pdf), to test activation of each injector ("Clock fuel injector 1" -- engine NOT running but ignition ON).

Please post the specific fault code(s) you have in DME Fault Memory. I presume this is for MSV70 DME in 2006 325i? See ISTA wiring diagram & Connector View for Cylinder #1 Injector & its 2-pin connector. That ScreenPrint is attached to NEXT post. For HOW to view documents, such as
"Fuel Injectors" SSP wiring diagram on your ISTA installation, see 2nd attached pdf.

Multimeter & Patch Cord Testing:
1) Test for 12V+ battery Voltage with Ignition ON at Orange wire at Injector Connector X6101/1 (socket #1 of connector);
2) "Tap" (DON'T hold) chassis ground to Socket #2 of Injector, to test for "Click". If injector activates, you have a wiring issue.
3) A "Noid Light" can be used to see if Ground Pulse from DME is being received at X6101/2, White wire, during cranking/running.

Please let us know what you find,
George

Thanks so much George. You're correct and my post was vague and confusing, I'm getting code 2E30 (among other non-DME comms faults).

I found the test plan. Injector #1 does not activate thru ISTA, but I get a satisfying few clicks when I try activating the others.

I am an OK DIYer but am utterly clueless when it comes to wiring diagrams/electrical. But I measured the resistance between the two pins on the injector itself. For injectors 2 & 3 I got values in the 12-13 range. For injector 1 it seems I got no resistance/an open circuit.

So seems pretty clear I need to replace injector 1. FYI I'm at 183k miles, the car is parked outside overnight, and the weather is starting to cool down here in the upper midwest.

[850CSi]

drawz cparke @cparke is the GB reman injector you used still going strong/any issues?

[drawz]

Originally Posted by 850CSi

drawz cparke @cparke is the GB reman injector you used still going strong/any issues?

It’s been working great since I posted. Only about 10k miles though.