[blowinsmoke]

I'm glad to have come across this forum. I just bought a 2010 335d with 72K miles. I knew it has issues but the price reflected that fact. I have a fairly significant mechanical background but this is a little different to the Duramax and other diesel engines I have experience with.

So I have a car that under light throttle hiccups and goes into a decreased power limp mode then with a little more pressure on the throttle, it dies. It starts right back up, but I have codes P0087, P0088, P2457, P124d. I have put a new fuel filter on and have inspected for pinched lines.

I have not taken it to dealer yet but have spoken to service manager who disclosed the possibility of the car having a failed High Pressure Pump. Like I said I'm no expert on these cars and don't know of any intrinsic faults other than CBU. I did notice the captive nature of the dealer in that there were several snotty comments basically expressing their desire for them to tell ME what's wrong rather than having me involved. I think they want possession and control. Due to the nature of my local dealer and my rather thin wallet, I would like to fix this myself. I can throw parts at it as well as they can.

Could it be the regulator on the back of the HPFP? Seems to me like a pump failure would cause a low rail pressure event but what explains the HIGH pressure? I've also read about DDE failures?
I basically do not know anything about the service history of the car, except that it has had new injectors and EGR at some point.

Any thoughts would be great!
Has anyone done a PCV reroute? That's a pretty common thing in the duramax world.

[kbsilver]

With all the emissions systems the 335D is one of the most complicated engines out there. You most likely have multiple issues, none of which seem to be the common ones. Not knowing the history or service history of the car certainly has one or both hands tied behind your back in trying to figure this out.

Good or bad the dealer may be your only way out. Hopefully you have access to a different dealer if one is being a jerk. One item I can add is most of the DDE issues were around falsely declaring bad injectors. I do not believe it gave the issues you are having.

For me except for needing CBU cleaning at 53K (covered by BMW), I've had a 100% trouble free experience in my 57K miles so far. I still have the original injectors.

Good Luck.

[135i_vs_]

I highly recommended at least getting a dealer diagnostics. An obd2 scanner will only help you so much.

[blowinsmoke]

That's good info about the DDE. My friendly dealer read off some of the service history but refused to give me a print out. In my experience, without conclusive evidence of the problem one must allow logic to rule the day. So if DDE failures are not common for these codes, in my mind I have 3 more choices. Pressure switch, regulator, or HPFP. I took off the fuel line after the filter off and ran a hose into a bucket. It LAUNCHED fuel after the electric fuel pump so I believe that the system is good up to the HPFP. Interestingly, I tried to suck fuel with an electric pump from the tank before the electric pump at the cars electric pump, but could not draw a drop. Is there a third pump in the tank(s)? Surprises me that I could not make that happen. My test electric pump is good, had a good seal since it actually stalled the pump. The car runs exactly like one would expect from a very very clogged filter. But as mentioned that's not it. It idles normally.

[glitdi]

Just because the pump is pumping does not mean the pump is defective.
It would be nice to know exactly what the working pressure of the pump is vs how much pressure that pump is actually producing. That being said I would focus your effort other places.
Yes you have an in tank lift pump, I would start with that one before throwing parts at it, a diesel fuel system is a very fickle thing and with the symptoms you are explaining I would at least investigate the in tank lift pump before I got to carried away.
I am a newbie here but still an experienced German Diesel mechanic here but I will say that its very suspicious how quickly the dealer defaults to replacing, injectors and fuel pumps. I think all the gas pot mechanics at the dealer just didn't know what the hell they are doing in a lot of ways. They may know bmw but they don't know the diesel engine.
While your at it clean the intake system, just because, who knows when it was done and its a maintenance item on these cars that seems to effect a lot of other systems. A lot of codes have been fixed here simply by doing some maintenance on the intake system.
Still leaning towards the in tank pump..

[blowinsmoke]

I will certainly check the lift pump separately then, now that I know it is there. I think I could check it the same way. I will put a gauge on it as well.

[335dFan]

Would the attached be helpful?

[Hoooper]

Can you list out what those codes mean? Just the generic obd definition would at least help.

[blowinsmoke]

p0087=Fuel rail pressure too low
p0088=Fuel rail pressure too high

The other two were under "pending codes"
p2457= "EGR cooling system perform"

The p124d says " manufacturer specific code" I have no idea what this one is.


I have ordered a scan tool with the BMW codes in in but who knows if that will work.

[floydarogers]

Originally Posted by Hoooper

Can you list out what those codes mean? Just the generic obd definition would at least help.

p0087 is rail pressure too low
p0088 is rail pressure too high
p2457 is EGR cooling plausibility
p124d is NOx sensor plausibility

(I did some fast googling.)

They're widely separated, and weird combo. You know what I would do - I would check t he voltage, even try a different battery. These cars are crazy sensitive to battery voltage and charging system, and these are all sensors of some kind. (If that off-beat solution works, don't forget to "register" the battery.)

[blowinsmoke]

Originally Posted by floydarogers

p0087 is rail pressure too low
p0088 is rail pressure too high
p2457 is EGR cooling plausibility
p124d is NOx sensor plausibility

(I did some fast googling.)

They're widely separated, and weird combo. You know what I would do - I would check t he voltage, even try a different battery. These cars are crazy sensitive to battery voltage and charging system, and these are all sensors of some kind. (If that off-beat solution works, don't forget to "register" the battery.)

What does that mean "register" the battery? I just put a new battery in the car. It's a napa battery if that matters.
The old battery was shot original battery. It would not hold charge.

[dixy2k]

The ECU needs to know there is a new battery installed. This is accomplished by "battery registration" with some software from the dealer or BMWHAT app. Otherwise the stupid ECU (which senses the old battery is bad and cannot figure out the new one is good) will overcharge the new battery.

[blowinsmoke]

That's unbelievable that in 2010 they couldn't make a system better than that!!! BMW shouldn't brag about that. Is there a chance it could cause my problem?

[9mmkungfu]

I would pop the intake off and take a look inside. At that mileage, CBU could very well be contributing to at least one of those codes.

[blowinsmoke]

Yet another angle! Can you tell anything just after the EGR?

[dominican]

register the battery first, see if that works. Buy yourself a borescope and look at the intake runners to see if you have CBU issues.

[dixy2k]

I've heard stories from my mechanic regarding poor (rough) running BMW's. In one case all he had to do was to tighten the oil cap. Another mechanic warned me about the fuel cap.
Better check those before you shell out a boat load of cash at the stealership.

[Yozh]

This is also a good reference document for you. Has some repeat material from the Advanced Blue doc, but also more.

Diesel Technology.pdf

[Hoooper]

Originally Posted by blowinsmoke

Yet another angle! Can you tell anything just after the EGR?

If you pull the EGR off and take a look into the intake you can get an idea. At that mileage your most likely options are that it either was recently cleaned or needs to be cleaned, and it should be clear which one it is by looking into the intake. If you can't tell, pull the intake off and look at the runners. You don't need any new gaskets and even for a first timer it should only take a couple hours to do since you said you have mechanical skill.

[BB_cuda]

Hooper, I never did run down the torque specs on the screws and nuts on the head side of the intake. Do you have specs for this?

I have pulled EGR and attempted using boroscope. After about 3-4" of insertion and trying to turn snake into 1st runner, the scope starts scraping against wall where junk is clinging. Result is the optic gets junk on it and you can't see from that point on. I tried to force the snake past a restriction too. It only goes about 1/2 way up the runner. I don't feel it possible to get snake up to intake port of head. Only way is to pull the intake. I wonder how well boroscope would fit into head inlet ports when intake is off. Should be much better. Good luck

[Mik325tds]

I agree with BB_cuda - it is close to impossible to get a look at your intake runners with a borescope using the EGR entrance to the manifold. You'd have to make a 90 degree turn and then a long straight. Doing that without bumping the side walls and getting your lens gunked up is impossible. The only way to tell if you have CBU buildup is pulling the intake, which really isn't that hard to do.

As for the problem with the codes, my best guess would be the rail pressure sensor. Getting a too low and too high reading could be contact resistance or a bad sensor.
Registering the battery and clearing all faults after that should be your first step anyway. Then run the engine and let us know which codes return.

The lift pump, as glitdi mentioned, has been known for problems on the E36 and many other cars, so that is definitely worth while looking after as well. The easiest way to test would be to disconnect the fuel line before your fuel pressure pump and run into a container. Have someone turn on ignition and see if you have a steady stream of fuel supply without bubbles.

[floydarogers]

Originally Posted by blowinsmoke

That's unbelievable that in 2010 they couldn't make a system better than that!!! BMW shouldn't brag about that. Is there a chance it could cause my problem?

Actually, it's a good system and extends the life of the batteries. You don't get something for nothing.

Probably not causing these problems, however.

About 10 years ago many of the manufacturers wanted to go to a dual-voltage system (that would have been the "best" solution), but couldn't get enough support; would have cost everyone in the industry "too much $$$".