[Cameron.335i]

Hi everyone i have a e90 n55 and I’ve been having issues. I have pulled all of these codes. I have ordered the lpfp as I have already done the hpfp and injectors does ANYONE know what could be causing this.
The car also will randomly die when idling and randomly get the engine malfunction reduced power car also has a long start which started after I replaced my hpfp and when I start it up it idles normal then revs up.

P0087

P13C9

P0171

P15DF

P10D9

[DrVenture]

P0087 - Fuel Rail/System Pressure Too Low

P13C9 - VANOS exhaust control camshaft stuck

P0171 - air-to-fuel ratio of your vehicle is too lean

P15DF - fuel pressure on the "high side" (after the high pressure pump) is too low - The fault is detected whenever the voltage of the rail pressure sensor changes by less than 0 V.

P10D9 - fuel pressure on the "high side" (after the high pressure pump) is too low

What was the reason that you replaced the HPFP in the first place? Or the injectors?

These appear to be all related to the HPFP, or the sensor or the signal to the HPFP. Except P13C9, which might be a separate problem. I'd solve the low pressure issue first and see if the other remains.

Rather than throwing parts at it, you could check the voltage/signal to the HPFP and the actual pressure on the fuel rail, if you have the skills and tools. The HPFP voltage is likely PWM. Pressure can be checked with certain scan devices or probably a gauge on the rail.

Maybe the new HPFP is faulty. Or damage to the harness. Or a faulty HPFP driver circuit. For which you are going to need a wiring diagram.

[Cameron.335i]

Ok so I replaced the fuel pump and injectors due to stuttering when under acceleration. But I fixed that jt was caused by the spark plugs and coild

[Cameron.335i]

Should I return the lpfp and purchase a new hpfp

[DrVenture]

Originally Posted by Cameron.335i

Should I return the lpfp and purchase a new hpfp

The codes are for high pressure, from what was posted. Not low pressure fuel pump. Were there any similar (HPFP) codes before replacing the pump?

I am assuming that the sensor is not the culprit, because there are actual symptoms of fuel starvation too (lean code). And a couple codes are from a voltage change detected, not the pressure sensor only.

I would also not suspect the HPFP driver circuit (in the PCM), if this started after you did fuel pump work. And when a circuit like that fails, it is usually all or nothing. Note that all my comment are generic, not BMW specific.

Start by closely inspecting the connector at the pump which you replaced. If the codes were not present before the new HPFP, it is potentially suspect. Is it an OEM pump? If not, even more suspect.

Also, aftermarket injectors can be sketchy.

have you tried putting back the original HPFP?

[Cameron.335i]

So it is a cheap Amazon pump and the codes were there before I did the change the injectors are used oem and I have not tried putting the oem pump because the codes were there before

[DrVenture]

Originally Posted by Cameron.335i

So it is a cheap Amazon pump and the codes were there before I did the change the injectors are used oem and I have not tried putting the oem pump because the codes were there before

If the codes were cleared and came back with a different HPFP, it may not be the HPFP. Or the connector at the HPFP. Which raises questions about the driver circuit and wiring.

Older Minnesota car raises the spector of harness corrosion too. Or rodent damage to the wiring.

But, if the low pressure pump is not feeding enough fuel to the high pressure pump, it could be an issue. IDK if there is a pressure sensor on the low pressure side of the system. Something to consider, because then the HPFP would be working harder and still not keeping up. This might produce all the stated codes, except the VANOS.

A scan tool that can monitor fuel rail pressures (low and high) and voltages, would be very helpful here.

[Cameron.335i]

So should go and try the lpfp and that doesn’t fix it go to the hpfp with it being a cheap one

[DrVenture]

If going the replacing parts route , then yes, try the LPFP. Having had the same codes with two different HPFP, makes it rather unlikely, but it cannot be ruled out.

This thread may shed some light. It suggests that at least some 3-series have a Low pressure fuel sensor, also that leaky injectors or certain vanos issues may be involved.

https://www.e90post.com/forums/showthread.php?t=943214

The problem here is the shotgun method, which usually leads to replacing things unnecessarily, as opposed to actual diagnosis and troubleshooting. Take it all with a grain of salt.

[Cameron.335i]

The reason I’m replacing parts is because it has 150k miles also the reason I believe it could be the hpfp if not the lpfp is the hpfp was a cheap Amazon one.

[Cameron.335i]

I swapped back to my old hpfp to see if I pull the codes I don’t remember for sure if it had the same codes before so I’m going to find out.

[Cameron.335i]

After changing back to old I pulled p0171 an the p13c9

[DrVenture]

I'd assume it isn't the HPFP, for now at least. Oddly, the LPFP sensor doesn't appear to be throwing codes. There may be a fuel pump delivery (FPDM) module associated with the HPFP, maybe check on that too. It would provide the necessary signal to modulate fuel pump pressure as needed.

[Cameron.335i]

I also just pulle p054b. Would the fpdm be in the lpfp. Also thank you for responding you have been very helpful

[Cameron.335i]

To solve p13c9 and p054b I’m going to try and clean my vanos solenoids

[DrVenture]

After cleaning, maybe swap the exhaust with intake (they may be same part number) to see if the code follows.

The fuel pump delivery/driver module is a separate control module that regulates the pulses to the fuel pump (PWM) to control its speed and thus pressure. It gets feedback from the pressure sensor to increase or decrease pulse width.

Here is an example, I do not know if it is used for LPFP, HPFP or both on your vehicle. Or if this is correct for your vehicle.

https://www.ebay.com/itm/16674357263...3ABFBMuO6K5LBk

Also, there were some issues with a high failure rate of HPFPs in certain BMWs around 2011, enough that BMW extended the warranty. That program would have expired by now, but does raise the chances yours went bad and the Amazon replacement is bad right from the box. I hate to even assume such, but the possibility exists.

[Cameron.335i]

Alright I’ll give it a shot I’ll wait on installing the lpfp. And try this first thank you for you help

[Cameron.335i]

Do you think this could be the solution to p0171 because that’s the only fuel related code I have pulled since I went back to the old pump. Or could it be a vacuum leak causing p0171 p13c9 and p054b

[DrVenture]

I'd follow the data. I don't think that a vacuum leak is causing a low pressure condition detected by a sensor in the fuel delivery system. But a low pressure condition could definitely cause a lean code.

As far as the VANOS codes, those seem pretty specific too, indicating issues with a stuck VANOS (P054B) possibly on exhaust (P13C9 previously observed). with luck it is just a failed/dirty exhaust solenoid.

The P0087 seen earlier might point to the LPFP. The P0171 could also be due to the LPFP. Which in turn triggered the HPFP codes. And the VANOS codes may just be a second issue. Some cleared codes may eventually come back too.