[lukechristy]

I just replaced my hpfp in my 2007 335i 6MT. All the previous codes that pointed to the hpfp(2AAF and 2FBE) and the symptoms of the bad pump(long startup and revs dying) were immediately fixed after I cleared the codes on MHD. The DME still throws a 29e2 code and shows the engine malfunction screen that is associated with limp mode. Anyone know why this code is being throw and what I can do to resolve the issue?

[WoodE30]

Originally Posted by lukechristy

I just replaced my hpfp in my 2007 335i 6MT. All the previous codes that pointed to the hpfp(2AAF and 2FBE) and the symptoms of the bad pump(long startup and revs dying) were immediately fixed after I cleared the codes on MHD. The DME still throws a 29e2 code and shows the engine malfunction screen that is associated with limp mode. Anyone know why this code is being throw and what I can do to resolve the issue?

Possible high or low fuel pressure sensor. You have anyway to read those pressures?

[lukechristy]

Originally Posted by WoodE30

Possible high or low fuel pressure sensor. You have anyway to read those pressures?

I have the MHD monitoring license. The lpfp sensor shows the pressure from the lpfp and it is normal(idle around 70-80). There isn't a hpfp sensor option in mhd and when I select the fuel pressure rail sensor it shows the same reading as the lpfp sensor, so it might be the same thing just different names. Only thing I could think of is injectors but there are not codes for any injectors, just the fuel rail pressure sensor code.

[WoodE30]

low pressure default pressure is 6.5 bar, if it doesn't move from 6.5 bar you need a new sensor. Low pressure sensor can cause a long/rough start.

[lukechristy]

Originally Posted by WoodE30

low pressure default pressure is 6.5 bar, if it doesn't move from 6.5 bar you need a new sensor. Low pressure sensor can cause a long/rough start.

After I installed the new hpfp I don't have a long crank or dying revs tho. The car idles normal and is making boost but it is still in limp mode.

[WoodE30]

Originally Posted by lukechristy

After I installed the new hpfp I don't have a long crank or dying revs tho. The car idles normal and is making boost but it is still in limp mode.

and your only fault is 29E2?

[lukechristy]

Originally Posted by WoodE30

and your only fault is 29E2?

Yes only code is 29e2, but I still have the limp mode engine malfunction screen.

[WoodE30]

Originally Posted by lukechristy

Yes only code is 29e2, but I still have the limp mode engine malfunction screen.

Best thing to do right now is do a log and see what the High and low fuel pressures are doing.

[lukechristy]

Originally Posted by WoodE30

Best thing to do right now is do a log and see what the High and low fuel pressures are doing.

Just started my car and did some monitoring via MHD. Lpfp sensor is showing normal psi at idle, but the rail pressure mimicked the psi of the lpfp sensor. Took the car for a drive and it seemed to be driving fine, making boost, and not bogging. Does this mean that I need to replace the fuel rail pressure sensor?

[WoodE30]

Originally Posted by lukechristy

Just started my car and did some monitoring via MHD. Lpfp sensor is showing normal psi at idle, but the rail pressure mimicked the psi of the lpfp sensor. Took the car for a drive and it seemed to be driving fine, making boost, and not bogging. Does this mean that I need to replace the fuel rail pressure sensor?

At idle the low and hi reading will be close to each other. Under load the high should be way higher. If it's not I'd say your hi/rail pressure sensor is bad. Make sure it's plugged in too.

[lukechristy]

Originally Posted by WoodE30

At idle the low and hi reading will be close to each other. Under load the high should be way higher. If it's not I'd say your hi/rail pressure sensor is bad. Make sure it's plugged in too.

I took the car out again to see if the rail pressure increased WOT. unfortunately it didn't and stayed within .2 psi of the lpfp sensor's reading. I guess this means a new rail pressure sensor. Thanks for your help, I will update once problem is resolved.