[cireo]

Good morning, l've been having sporadic issues with my 08 335xi. I'm throwing 2 codes occasionally p2ef4 p30ff. I've changed the boost solenoids 2 times and thermostat was changed 3 times. 2 times same day for codes. recently when When the codes appear the car goes into limp mode. Shut it off then runs fine again till the next time it acts up. I want to say it does it more in the warmer weather or when the cars runs for a while and noticed the last 3 times going up a hill triggered the limp mode. Yesterday I noticed the charge pipe was a little loose when manipulating it. Maybe the o ring is shot and ill replace the clip. any ideas?

[Cloverdale]

You can check boost solenoid functionality with an inexpensive vacuum pump. I have several new ones that don't work. They're designed to allow a pressure bleed when bench tested. The malfunctioning ones remain pressurized and don't bleed when bench tested. By bench tested I mean applying vacuum to the outer most stack while holding a finger over the inner stack and pressurizing to say 20 and watching it release the pressure over the course of about 10 seconds (if functioning). The new but non functioning solenoids I have don't release the pressure at all (they're cheap knock-offs from China).

[cireo]

i changed them 4 years ago then last year. when i installed the last set had lots of power then an hour later code went off again. was thinking to replace them again and test the old ones. i'm not sure if something else could cause the boost solenoids to fail. been to several mechanics. haven't found a good one that doesn't just want to throw parts instead of isolating the issue

[Cloverdale]

Originally Posted by cireo

i changed them 4 years ago then last year. when i installed the last set had lots of power then an hour later code went off again. was thinking to replace them again and test the old ones. i'm not sure if something else could cause the boost solenoids to fail. been to several mechanics. haven't found a good one that doesn't just want to throw parts instead of isolating the issue

Any from Asia / China (which could include ones purchased from many US sources) don't function internally despite looking like they're supposed to look. Attach the vacuum pump hose (only one stack will hold pressure) and take pressure to 20 while holding a finger over the other and see if it bleeds off (as it's supposed to). Pierburg seem to be the only reliable brand. .

[cireo]

that's where i bought them pierburgs. it's possible they were defective. i may exchange them under their warranty i try another set

[Cloverdale]

Originally Posted by cireo

that's where i bought them pierburgs. it's possible they were defective. i may exchange them under their warranty i try another set

If they're Pierburg (the only brand I'd trust) I suspect they're functioning properly. Let us know if they're not.

[cireo]

i can test them in place with a vacume pump without removing them by using the vacume lines that are already attatched?

[cireo]

i just picked up a loaner hand held vacume pump at autozone. tested the rear at 20 dropped to 19 in 2 mins the rear at 20 dropped to 16.5 in 2 mins roughly

[Cloverdale]

Originally Posted by cireo

i just picked up a loaner hand held vacume pump at autozone. tested the rear at 20 dropped to 19 in 2 mins the rear at 20 dropped to 16.5 in 2 mins roughly

I've only tested removed in which the pressure falls to zero within 10 or 15 seconds as I recall. Perhaps they're holding pressure while on vehicle cause the line / stack your not pressurizing isn't disconnected?

[cireo]

the ones i had lying around when tested pressures drained immediately. the ones on the car bled slowly. all the videos i watched the pressurized while on the vehicle. from what i understand they bleed off slowly. one was just faster than the other. also its been said they can still be defective either way. fcp said they are sent back more frequently that other parts. i'm still in the same spot. i've got to find a good bmw mechanic in ct or new york.

[cireo]

checked again today they don't hold any pressure like yesterday. i did hook to line to waste gate they close and hold pressure

[Cloverdale]

Originally Posted by cireo

checked again today they don't hold any pressure like yesterday. i did hook to line to waste gate they close and hold pressure

I doubt boost solenoids are responsible for your limp mode.