Boost troubleshooting

AlexRF10 · 05-05-2020, 05:44 PM

Quote:

Originally Posted by 95blkmax

Quote:

Originally Posted by AlexRF10

I was also trying to find any boost or vacuum leaks on mine. I took off the same vent pipe you replaced and inspected it. If I blow into the charge pipe end it comes right out through the intake pipe end. I'm wondering how that pipe holds psi in the charge pipe if I can easily blow through it, or my vent pipe needs to be replaced. Do you know if your new pipe does the same?

No sir this is a purely un-checked pipe. Under vacuum conditions the fuel tank vent valve at the T of the pipe clicks to vent vapors into the intake tract, and closes during boost conditions.

I honestly don't understand why this is just an open pipe between the CP and the turbo inlet pipe. I can only make an ASSUMPTION that BMW engineers felt that releasing some of the boost at the CP and dumping it at the turbo inlet assists in spool-up (and in a way, create a scavenging effect/ vacuum pull so as the fuel tank vent valve could still vent out even during boost conditions). But again, these are assumptive theories lol.

Oh ok thanks for the info. So the purge valve controls opening and closing of the pipe. I think I read in ISTA that the purge or vent valve will send gases in to the CP and intake pipe, I just wasn't sure how it gets closed off to not have a huge boost leak.

95blkmax · 05-05-2020, 07:53 PM

Quote:

Originally Posted by AlexRF10

Oh ok thanks for the info. So the purge valve controls opening and closing of the pipe. I think I read in ISTA that the purge or vent valve will send gases in to the CP and intake pipe, I just wasn't sure how it gets closed off to not have a huge boost leak.

yup! it itself is a solenoid so it can close and open to regulate flow per DME control