[robc1976]

I have heard that if your boost solenoid goes out you get a under boost code 30FF...but if they are weak you will just be under target due to the Wastegate not closing all the way. Each solenoid has 2 vacuum nipples, wich one shoud I draw vacuum on to see if there are working properly (hold vacuum)? Do you know of a better way to test these? "Vroom" has a very great thread for testing these that involves a T and driving WOT with a line and gauge coming thru the window....I would do this but have nobody to read the gauge while I am going WOT in 3rd lol!!

Should I just see if it each selonoid will hold vacuum? Should anything be connected...like the other lines when testing these?

[JamesM3M5]

I've seen a bad solenoid that failed to hold vacuum just from testing with a mityvac hand-held vacuum pump. That was indication enough to replace it. The other solenoid did hold vacuum just fine. Put your vacuum on the port that comes from the vacuum pump.

[George@V]

cleared wrong info.

[robc1976]

Originally Posted by JamesM3M5

I've seen a bad solenoid that failed to hold vacuum just from testing with a mityvac hand-held vacuum pump. That was indication enough to replace it. The other solenoid did hold vacuum just fine. Put your vacuum on the port that comes from the vacuum pump.

Thats what I am using "mightyvac"....I am guessing the port you are referring to is the one that is connected to the vacuum canister? The other is spliced. Should I disconnect everything off the selonoid?

[robc1976]

Originally Posted by JamesM3M5

I've seen a bad solenoid that failed to hold vacuum just from testing with a mityvac hand-held vacuum pump. That was indication enough to replace it. The other solenoid did hold vacuum just fine. Put your vacuum on the port that comes from the vacuum pump.

You where right on the money man!! The boost selonoid closest to fire wall is bad...I put 20"Hg to it and the needle just falls to "0"Hg with in 15 seconds. The other selonoid holds vacuum easily. I am guessing the selonoid does not have enough vacuum to hold the Wastegate shut.

[George@V]

Originally Posted by robc1976

You where right on the money man!! The boost selonoid closest to fire wall is bad...I put 20"Hg to it and the needle just falls to "0"Hg with in 15 seconds. The other selonoid holds vacuum easily. I am guessing the selonoid does not have enough vacuum to hold the Wastegate shut.

The solenoid doesn't use vacuum to hold the wastegate shut. The wastegate actuator rod keeps the wastegate flapper shut, and opens it with BOOST.

Which line are you guys disconnecting on the solenoid to test it?

[Lulz_M3]

Actually it's the opposite, it uses vacuum to close the waste gates and hold them closed. They literally function the opposite of every other wastegate system I've seen in the past.

[robc1976]

Originally Posted by George@V

The solenoid doesn't use vacuum to hold the wastegate shut. The wastegate actuator rod keeps the wastegate flapper shut, and opens it with BOOST.

Which line are you guys disconnecting on the solenoid to test it?

My supra was like that, but the N54 is different...the line coming from the canister.

[George@V]

Originally Posted by Lulz_M3

Actually it's the opposite, it uses vacuum to close the waste gates and hold them closed. They literally function the opposite of every other wastegate system I've seen in the past.

Wow, that's surprising to me. Thank you for clarifying.

[robc1976]

Originally Posted by George@V

Wow, that's surprising to me. Thank you for clarifying.

I agree...it is VERY surprising lol!!

[George@V]

My apologies for my earlier post.

[robc1976]

Originally Posted by George@V

My apologies for my earlier post.

No need for apologies, you put good Info in he thread

[Joshboody]

Alright, i'm a little confused now. With no power i would think vacuum through the solenoid means nothing. You would have to check with engine running measuring post solenoid vacuum. I've done this and each solenoid was very close. Due to this thread i checked each solenoid engine off and they bleed at different rates... one considerably faster. Does this really mean something?

I do run kinda high DC compared to others.

[robc1976]

Originally Posted by Joshboody

Alright, i'm a little confused now. With no power i would think vacuum through the solenoid means nothing. You would have to check with engine running measuring post solenoid vacuum. I've done this and each solenoid was very close. Due to this thread i checked each solenoid engine off and they bleed at different rates... one considerably faster. Does this really mean something?

I do run kinda high DC compared to others.

From my understanding both selonoids together control both turbos/wastegates. Mine bleed off fast...I mean I pumped 20" Hg to the first selonoid and the needle just started dropping not holding vacuum and went to 0"Hg....the other selonoid held vacuum with out dropping. I run a very high Wastegate duty cycle 100% on a log & at 130 (maxed out) and I have a 15 ohm mod. Both selonoids are the same thing/part so they should both hold vacuum.....correct me if I am wrong.

Here is thread about this also:

http://www.e90post.com/forums/showth...9#post11131988

[Joshboody]

Ok I checked today... solenoids have to be active (running a DC) to check them. My pump is pulling 25" to and 17" from each solenoid (on map0).. that's 68% which is accurate to my software I believe.

So again have to check with engine running comparing that post solenoid is equal and make sure to check the pump.

[robc1976]

Originally Posted by Joshboody

Ok I checked today... solenoids have to be active (running a DC) to check them. My pump is pulling 25" to and 17" from each solenoid (on map0).. that's 68% which is accurate to my software I believe.

So again have to check with engine running comparing that post solenoid is equal and make sure to check the pump.

Curious though, did you check with engine off to see if it would bleed out?? On the cars I saw tested they would all pull vacuum and not bleed out on both selonoids! But mine did LOL!......going to to go do your test now!! Awesome info! I got 2 brand new ones and that sy I know there good lol!! Well hopefully.

[robc1976]

Just for anybody reading this thread a going to get used ones or something....they have to be hooked up to the car or they will not hold vacuum....I can see someone taking a selonoid of a used car or something, testing it and thinking its junk....just throwing that out there.

[robc1976]

Did a test, pulling 22"Hg from vac canister.....also tested how much vac was being pulled to each actuator snd it was 11"Hg at each end so if I had a T it old have been 22"Hg so maybe the selonoid was not bad? But why is it all 3 cars of friends ll old vacuum with motor off but the one of mine does not...we all have 20-22"Hg from pump except my buddy with a 2008 E90 who has 25-26"Hg at the pump?? Wierd

[M3 Eater]

two nipples on each solenoid, one to wastgate and one to the Vac Canisters. One nipple holds vac with car off, the other one does not. Canisters show 20 at idle, solenoids show 15.

Boost is on target but WPM is always off the chart.

[robc1976]

Update, took off the suspected bad selonoid snd I believe it was bad....the old one I can blow in the nipple and suck in air thru the nipple (no pun intended lol!!!)....the new one I can not. That would tell me the selonoid is probably bad....anyone else think the same?

[robc1976]

Will post before and after log, the replacement of the selonoids did the trick...almost 100% on target...best log car has ever ran wastegate adaption went from 130 to 112.

[robc1976]

here is comparision of before and after selonoid replacement.