[iceMuffin]

2007 335ix with "hybrid turbos". MHD 2+ tune, love the car, very fast. One day at an intersection the car turned off. Car would kinda turn back on, but would die immediately. Full tank of gas.

Cleared the codes with the code reader, no start.
I bought a new HPFP and installed it, no start.
Sprayed starting fluid in the intake, car runs fine!!!!! but only with the starting fluid.

I unplugged the 2-pin electrical connector on the HPFP, a buzzing noise stopped, but the car still would not start. I did this because I think the DMU is telling the pump not to build pressure because it is in a fail-safe mode. ("INJECTION IS DEACTIVATED" LOL, kinda hard to argue with that)

Attached are the screenshots of the code reader. the car has a mix of index 7 & 9 injectors, suspect injector #6 of being clogged as the car has a rough idle.

What are the next troubleshooting steps? can I run 12-volts to the pump to force it to create pressure? the code reader says fuel pressure is 2500 hpa (~35psi) meaning the LPFP is pumping fuel to the HPFP.

Thank you for reading this, I appreciate your time.

[The_E92_Fan]

MSD80? I’d start with the cheapest option, check the MOSFETs.

[iceMuffin]

The fourth line in my post says it runs on starting fluid. This means the MOSFETs are firing the coils properly. The hpfp is not generating pressure. The error code says "INJECTION IS DEACTIVATED" I want to focus on changing the mode from deactivated to activated.

[lowrydr310]

Originally Posted by iceMuffin

The fourth line in my post says it runs on starting fluid. This means the MOSFETs are firing the coils properly. The hpfp is not generating pressure. The error code says "INJECTION IS DEACTIVATED" I want to focus on changing the mode from deactivated to activated.

These MOSFET transistors drive the injectors. Your HPFP could very well be generating pressure and the injectors aren't opening when they're supposed to.

However you clearly have a high pressure fuel side low pressure fault, which I assume is based off the actual pressure sensor. Maybe that high pressure sensor is bad?

Also, 35psi is very low for the low pressure side.

[The_E92_Fan]

Yeesh dude

[iceMuffin]

Bump for attention. Took the car off insurance, still don't know what to do. Still have the following questions:

-How do I erase this code so that the car will turn on again?
-What do I need to buy to be able to erase this code?
-I purchased MHD, can I use MHD to disable this code?
-Is this normal? have you ever seen this before?
-Are there any shops near minneapolis that specialize in BMW tuning?

WILLING TO SEND MONEY VIA PAYPAL/VENMO IF YOU HELP ME GET IT RUNNING.

[TiAgAu]

Low pressure fuel pump should not be that low. I would start there.

[iceMuffin]

Originally Posted by TiAgAu

Low pressure fuel pump should not be that low. I would start there.

Is there any reason why you want me to troubleshoot an issue that is a non issue? The LPFP is pumping fuel into the HPFP just fine. I require that the car be able to run in a degraded state. In other words if the computer detects a value out of spec it is OK to throw a check-engine-light, but it is NOT OK to turn the injectors off.

Of the dozens of cars I've owned, I can think of no other car that shuts off when a minor issue arises. This is why the term "limp-home-mode" was created.

Option B is a full standalone system, so anyone please chime in.

[ptpending]

if you are sure that your lpfp is fine, then one of you injectors failed and not keeping the pressure
this will lead to hydraulic damage (liquid cannot be compressed) and you will have to replace whole engine
thats why the DME not allowing you to start engine
every N54 owner in their owning time should replace all injectors to revision 12 injectors and hpfp.

[iceMuffin]

Originally Posted by ptpending

if you are sure that your lpfp is fine, then one of you injectors failed and not keeping the pressure
this will lead to hydraulic damage (liquid cannot be compressed) and you will have to replace whole engine
thats why the DME not allowing you to start engine
every N54 owner in their owning time should replace all injectors to revision 12 injectors and hpfp.

I completely agree with you 100% everything you said.

HOWEVER

I still want the ability to clear the codes to turn my car on in a degraded state.

[ptpending]

Originally Posted by iceMuffin

I completely agree with you 100% everything you said.

HOWEVER

I still want the ability to clear the codes to turn my car on in a degraded state.

you may remove the spark plugs and find which of them more wet or dark and then replace injector in this cylinder
this may temporarily allow you to restore pressure and engine will start

[iceMuffin]

Originally Posted by ptpending

you may remove the spark plugs and find which of them more wet or dark and then replace injector in this cylinder
this may temporarily allow you to restore pressure and engine will start

My goal here is to be able to override the safety systems. Currently, the safety systems are overriding my ability to start and move the car up and down the driveway. For the future I need to be able to do this, just waiting for the right person to chime in.

[ptpending]

ok, it is not possible technically run HIGH PRESSURE SYSTEM without PRESSURE.

[iceMuffin]

Originally Posted by ptpending

ok, it is not possible technically run HIGH PRESSURE SYSTEM without PRESSURE.

Theres plenty of pressure from both pumps.