[Algold415]

Hey All,

Hoping to get some help or insight on my issue that I've been chasing for months. I purchased a 2010 BMW 335D a few months back, it wouldn't start.

I sent all (6) injectors to a shop for testing. All injectors had a weird issue connecting to the Bosch testing machine, so the shop deemed all (6) faulty (but the tech said it might still run if I replaced a couple of injectors that looked the most caked up with carbon.

I purchased (2) new injectors from Ebay and installed them in place of cylinder 3 & 5. The car started up and after some smoking a bit ran quite well.

Almost right away, I started getting code 4580 (Rail-pressure plausability, delivery controlled) - Engine Limp Mode. I tested the specified and actual pressure, and I'm getting double actual vs specified ONLY AT IDLE. (For example 500bar/250bar at idle). Weird thing is that when I drive on the freeway, car drives perfectly, no Limp Mode! I read multiple posts with this issue and it seems everybody has either something small that fixed the issue or they didn't end up figuring it out.

Here are the things I've done so far and parts I've replaced:

1. Replaced: Fuel Filter

1.1 Replaced: Quantitative Fuel Control Valve at the HPFP (purchased new)

2. Replaced: Fuel Pressure Sensor & Fuel Pressure Regulator & Fuel Rail (purchased as a set, used on Ebay, but tested and functioning)

3. Checked: All fuel return lines (from fuel rail & HPFP to gas tank). Other than a small kink in the line, didn't seem to have any restrictions (I even started the car with the line off at the fuel delivery unit(driver's side), and the return fuel literally filled a water bottle within 5-10 seconds of running. (I'm aware of the return fuel line blockage bulletin: https://static.nhtsa.gov/odi/inv/201...003-49621P.pdf)

4. Multiple members on the diesel bmw facebook group suggested that they had the same code on their vehicles and it ended up being faulty injectors. They suggested to do a leak down test.

5. Performed: Leak down test on all (6) injectors. Almost all fuel leak down levels were equal. Only (2) injectors had about 1/8" more diesel in the water bottle after running for ~13 minutes.

I'm stuck here and have no idea what to do next. Do I buy (4) more new injectors and hope this fixes my issue. It might end up being a $1000 expense I didn't need to make.

Help Help Help!! I just want to fix the car and enjoy driving it already!! Thanks all

[thewheelm4n]

I'm in the same exact boat with my 2011 335d. Purchased it back on March 27th and code 4580 Rail Pressure Plausibility Quantitative Control code/low power mode came on 40min into the drive home from the dealership and I have not been able to remedy it since. I'm about $3k into the car at this point. HPFP, Fuel Filter, Fuel Pressure Sensor/Regulator, Throttlebody, fully updated software for all modules, full carbon cleaning, still getting the same issue. Pressure from low pump is good. Have never gotten a single misfire or injector related code, or actually any other codes of any kind. Have had it at 3 shops. Shop its currently at discovered that return line bulletin you posted last week, I've ordered those lines but now after seeing your post I'm wary it still won't fix it. I have a loan on the car and am tearing my hair out with this. I had another 2011 last year and had almost zero issues with it. I too am at a loss.

[Algold415]

@thewheelm4n

I feel your pain.. My 335d drives perfectly otherwise, it only triggers the 4580 when the RPMs drop to idle. I took it out yesterday for a long freeway cruise, and had the limp mode go on a couple times as the car was coasting down a hill, otherwise it ran like a champ.

I'm starting to think this might be some kind of electronic problem either with the DDE or the Fuel Control Module (16147229173) - see attached pic.

Yesterday, I used my Foxwell scanner and took a look at the 'Control values for speed control' of the LPFP. The actual speeds (in RPMs) jump all over the place from ~1600 to ~3500, which looks absolutely inconsistent. I wish I could post a video here, but I don't think it would attach, since it's a big sized file. I did the same test on my X5 35D, and although the RPMs jumped kind of inconsistently as well on the scanner, it wasn't such an extreme deviation, going from ~1800 to 3500 rpms up and down like the 335d.. I'm not sure if perhaps the scanner is too slow or not showing the proper values but it definitely seems like something to look into.

Also, another thing I noticed and will attempt to check, the Fuel sending unit(under the back seat, driver's side - part 16117190947) has the fuel return hose that has a 'pressure relief valve' on the end of it. I'm wondering if these valves can fail or get clogged up and cause the return line to be backed up? - (see attached pic).

Please keep me posted if you make any progress on your end!

[Algold415]

I tested the LPFP and its sending unit today. There was a bunch of small particles in the LPFP, I cleaned them up, checked the lines for the sending unit. All seems ok visually. Also, I took out the fuel pump module and it also seemed fine.

At this point I'm conteplating either replacing the rest of the old injectors or replacing the LPFP, sending unit, module, and fuel return lines, and hoping one of those might help.

But before I do either, I'm getting a fuel pressure testing kit and will be checking the return fuel line pressure. Also planning to replace the thermostat as it looks like mine is stuck open and not letting the regens happen.

Will report back if any progress ends up happening on my end.

[thewheelm4n]

This is so crazy man...I'm 6 months and $4k into mine and still no resolution to 4580 issue. Same symptoms really, usually low no lower power mode on the highway or cruising but as soon as I come off an exit ramp and come to a stop, bam there it is almost every time. Makes me think its some sort of low pressure issue. I had the shop its been at for the past 4 months, who found that bulletin regarding fuel return lines, replace the 3 fuel return lines, but still didn't fix it. At this point I'm at a loss, I've got one more shop to try locally but of course they can't even get me in until October 13th. I'm totally out of money and motivation to keep at this but I have a loan on the car so I have to fix it even if I'm going to try to sell it. Unbelievable. Any progress?

[e90Noobie]

This may not have anything to do with your problem but thought i'd post it just in case.

https://www.tunemyeuro.com/low-rail-...ry-controlled/

[Algold415]

Originally Posted by thewheelm4n

This is so crazy man...I'm 6 months and $4k into mine and still no resolution to 4580 issue. Same symptoms really, usually low no lower power mode on the highway or cruising but as soon as I come off an exit ramp and come to a stop, bam there it is almost every time. Makes me think its some sort of low pressure issue. I had the shop its been at for the past 4 months, who found that bulletin regarding fuel return lines, replace the 3 fuel return lines, but still didn't fix it. At this point I'm at a loss, I've got one more shop to try locally but of course they can't even get me in until October 13th. I'm totally out of money and motivation to keep at this but I have a loan on the car so I have to fix it even if I'm going to try to sell it. Unbelievable. Any progress?

Unfortunately no progress on my end. I'm basically narrowing it down to replacing one of these components, either choice is bad since it will cost close to $1000 per area:

LPFP & Sending Unit
-Overall, code 4580 seems like a mechanical fault, like something is causing the blockage of the return fuel. Both the LPFP and it's sending unit have these 'pressure relief' valves that might cause the pressure build up. I tried searching online to purchase only these valves, but they don't seem to be sold separately, so have to buy the fuel pump+sending unit to really eliminate those components as a cause of the fault

-I removed the return fuel line (in the engine bay) and tried to 'blow' through it and it was pretty difficult to do so, seemed like there's a lot of pressure in the line - meaning one of those 'pressure relief valves' are doing it's job? I know this sounds like a dumb test and I honestly don't know if there's supposed to be any pressure or just 'blow' through easily..

-A few members on the FB group suggested that my LPFP might be faulty and is 'pegged' at maximum flow during operation. Hence, when the vehicle isn't in idle, it's working fine. As soon as it idles, the pressure builds up since the LPFP doesn't reduce the flow. I tried to listen to the pump from the top of the rear seats and a few times it seemed to be working inconsistently.

-Planning to attach a pressure tested to the return lines and seeing what's happening with a mechanical gauge.

Injectors
-As I mentioned earlier, when I tested the injectors at the diesel shop, they all came back 'faulty'. The technician said that they might still work but they don't 'communicate' with the ECU. I only replaced (2) which was enough to make the vehicle run. So my though is, what if the remaining (4) that I left in are basically giving the ECU bad info on the flow rate, etc. That might mean that the ECU will use the fuel sensors on the HPFP & Rail to compensate/fix the fuel issue, possibly triggering the high fuel pressure?? It's just a theory, but I'm a bit more apprehensive thinking this might be injectors. However, 2 or 3 people on FB group told me the injectors fixed their 4580.

This is really where I'm at right now. I don't know which direction to go with, but I'm leaning more toward replacing the LPFP & Sending unit. I will keep you posted if I make any progress. Hang in there, we have to figure this out for the sake of the BMW Diesel Community

[Algold415]

Originally Posted by e90Noobie

This may not have anything to do with your problem but thought i'd post it just in case.

https://www.tunemyeuro.com/low-rail-...ry-controlled/

Thanks! This is definitely for the 4560 & 4570 codes which is usually the opposite of my issue, it's for 'Fuel Pressure Too Low'. I think that happens when either the LPFP doesn't send enough fuel to the HPFP. Or if the HPFP is faulty (crack in housing, etc) and doesn't fill the Fuel Rail.

Appreciate the suggestion though!

[Algold415]

Originally Posted by thewheelm4n

This is so crazy man...I'm 6 months and $4k into mine and still no resolution to 4580 issue. Same symptoms really, usually low no lower power mode on the highway or cruising but as soon as I come off an exit ramp and come to a stop, bam there it is almost every time. Makes me think its some sort of low pressure issue. I had the shop its been at for the past 4 months, who found that bulletin regarding fuel return lines, replace the 3 fuel return lines, but still didn't fix it. At this point I'm at a loss, I've got one more shop to try locally but of course they can't even get me in until October 13th. I'm totally out of money and motivation to keep at this but I have a loan on the car so I have to fix it even if I'm going to try to sell it. Unbelievable. Any progress?

Today I received a LPFP that I purchased used on Ebay.. it arrived with a huge hole on the bottom of the fuel pump base I'm starting to think this car doesn't want to get fixed. I was trying to save a bit of money on a used part, but I guess might as well buy everything new.

By the way, I'm not sure if you have seen this post, but it describes exact issues that both of our cars are having. I reached out to the owner on that thread, but so far haven't heard back. Check out this thread if you get a chance:

https://www.e90post.com/forums/showthread.php?t=1639785

Any updates on your end? Have you tried getting your injectors bench tested? To see if any of them might not be working properly? That might be the next cheapest thing for you to try, if you haven't already.