[atroyan]

Hi All,

Got an 08 335xi 72,000 miles. Jb4 g5 board, meth, catless dp, full exhaust. Sunday morning went to drive the car and I have 0 boost. The other day it was throwing the exhaust vanos and low boost so I first tried cleaning the vanos and then got a new exhaust vanos. Anyways I am getting 0 boost, doesn't matter which map on the jb4 as well as which backend flash I have loaded. Did the vacuum test Terry posted a while back and have 0 vacuum and I also have 0 vacuum above both canisters. What would be the next step in diagnosing this issue?

Also one stupid question, for the inlet and exhaust vanos connections if you are looking at the front of the car, is the connector for the inlet vanos (top sensor) to the left (passenger side) and the connector for the outlet vanos (bottom sensor) the harness that comes from the right (driver side) that is longer.

Thanks

[georgelb]

The no vacuum is odd though; did you accidentally disconnect the brake booster connection? That might create a bit of an issue in getting vacuum to the canisters.

In any case, here's an image of the connections.

[atroyan]

Thanks, that was one of the first things I thought, but I looked at the booster line and did not see anything. I'll visually inspect it again this evening. I did break it years ago the connector that I had to get replaced but when it was broke I remember I had no brakes and it was running like crap. It is running fine and no error codes, just 0 boost. My brother was watching as I was doing vacuum test and revving and the rear waste gate seems not to be moving at all. On the jb4 in the logging I can see the PWM go 100 and back down fine.

[atroyan]

Here's a log doing 0-80 with no boost.

[georgelb]

I'd pull that brake booster line off with the car running and see if you have vacuum there, then follow the lines to the canisters. The two lines coming off it run straight to the bottom of the canisters from there, after passing through some semi-hard lines, and if you have no vacuum at the top of the canisters then something in that path is wrong.

[atroyan]

Thank you I will try that out....

[cstmx_ryder]

it could be the vacuum canisters, vacuum lines, and maybe the boost solenoids....etc

[Ingeniator]

If both canisters have no boost. It is the vacuum pump. It could be the pump or the drive cog. Either way you should stop driving the car incase the oil/hp fuel/cams are not being driven correctly.

[atroyan]

Hi Ingeniator, any good way on testing out the vacuum pump?

[Ingeniator]

If you trace the vacuum lines back to the pump you should check for vacuum there. It has been know to fail but you should verify all lines first. It is unlikely for both lines to clog though which is why bmw designed it this way. If the pump doesn't pull vacuum it needs to be replaced.

The nipple on the back side.
http://realoem.com/bmw/showparts.do?...58&hg=11&fg=45

Lines 5&6
http://realoem.com/bmw/showparts.do?...75&hg=11&fg=45

[atroyan]

Thanks, do you know which harness for each vanos goes where? that's the only other thing I can think of is that I have the vanos harnesses switched. If you are looking at the car, I have the inlet (top) vanos hooked the shorter passenger harness and the exhaust (bottom) vanos hooks to the longer driver side harness.

[Ingeniator]

Originally Posted by atroyan

Thanks, do you know which harness for each vanos goes where? that's the only other thing I can think of is that I have the vanos harnesses switched. If you are looking at the car, I have the inlet (top) vanos hooked the shorter passenger harness and the exhaust (bottom) vanos hooks to the longer driver side harness.

Can't remember. I'll stop by my shop today and look for you.

[atroyan]

Thank you so much, if its easier, my cell is 724-713-7959

[georgelb]

Originally Posted by atroyan

Thanks, do you know which harness for each vanos goes where? that's the only other thing I can think of is that I have the vanos harnesses switched. If you are looking at the car, I have the inlet (top) vanos hooked the shorter passenger harness and the exhaust (bottom) vanos hooks to the longer driver side harness.

They go like the picture I posted above, and as you just described. The one coming from the passenger side goes top, and the other goes bottom.

[atroyan]

Thanks for all your help, I got it figured out, sure enough, the vacuum lines by the brake booster, both lines dry-rotted off. replaced and everything is back to normal.

Thanks

[georgelb]

Originally Posted by atroyan

Thanks for all your help, I got it figured out, sure enough, the vacuum lines by the brake booster, both lines dry-rotted off. replaced and everything is back to normal.

Thanks

Good to hear!

[Beau93315]

Originally Posted by atroyan

Here's a log doing 0-80 with no boost.

Dear god, how long did that log take? I cant imagine going 0-80 N/A.


On a serious note someone beat me to it, I am glad its running good

[tinnsoldaten]

Are u running a meth system on that car

After driving , open hood and go to vacuum canisters , pull top hose from it , if there is vacuum there you should be good.
Other thing to do is make a T and hook it up between vacuum supply to wastegates , have a meter on the end of the hose and lead it to inside cabin , go for a drive and see if you have any vacuum while WOT. If not, your vacuum solenoids are gone or your wastegate signal cut , from failsafe from methsystem or similar.

I just had same issue , but I had the 30FF underboost code everytime I went WOT.

I had meth system with empty tank and failsafe cutting my wastegate signal.

Good luck