Typical BLM changes w/ PCV capped?

YGETV8

I think, therefore I am??
Joined
May 24, 2001
Well, finally got around to pulling and capping the vacuum block lines one at a time to chase my high BLMs. No changes till I did the PCV... watched as my BLMs slowly dropped from 150 to about 143 then I stopped there, but they may very well have continued! I have the correct AC Delo valve coming in today, and I understand that may help. Going to install it with some silicone around it and the intake grommet and zip ties around all hose ends.

The real question is: Does anybody know what is a "normal" change in BLMs when the PCV is connected? I mean, it's JOB is to pull *some* air in under vacuum, right?

While we're on the subject of BLMs, I do have some exhaust leaks at the turbo flange (which I *will* fix), but isn't that too far past the O2 to make a BLM difference?

Thanks, Jay
 
Well, finally got around to pulling and capping the vacuum block lines one at a time to chase my high BLMs. No changes till I did the PCV... watched as my BLMs slowly dropped from 150 to about 143 then I stopped there, but they may very well have continued! I have the correct AC Delo valve coming in today, and I understand that may help. Going to install it with some silicone around it and the intake grommet and zip ties around all hose ends.

The real question is: Does anybody know what is a "normal" change in BLMs when the PCV is connected? I mean, it's JOB is to pull *some* air in under vacuum, right?

While we're on the subject of BLMs, I do have some exhaust leaks at the turbo flange (which I *will* fix), but isn't that too far past the O2 to make a BLM difference?

Thanks, Jay


Raises a couple of points. What's the part number of the new PCV you have coming?
BTW, yes, the wrong pcv can have a drastic affect on your BLM's. That's why getting the "correct" one is SO important.
ANY pre-turbo exhaust leak will also cause in increase in BLM numbers.
 
It's the AC "893" numbered one... supposed to be the correct one. Just put it in and letting the silicone set up before I try it.

Off to order an RJC turbo flange gasket! Thanks for the reply Dave!
 
Well, also zip tied the hoses to the PCV and check valve, and sealed it with The Right Stuff in the grommet (justin case). Drove around on it and now my BLMs seem to have settled around 139-ish when fully warm and in park. Getting better!
 
I know that my BLMs dropped a good bit when I sealed up my engine. I left the PCV in there but blocked the valve covers in, just as a test, to see how much it affected my idle BLMs. Don't remember what the change was, and I don't seem to be able to make sense of the DirectScan runs I saved (should have commented them better!), but I do know it was pretty significant - probably 10 numbers or more.

John
 
Been fighting a severe cold start driveability issue along with the BLMs. Car seemed to run WORSE for the first three minutes the more I tuned it. For kicks, I bumped the Translator idle up to 10% rich. Runs smoother cold and now BLMs are 129. Not the best way to "fix" a BLM issue, but...
 
Been fighting a severe cold start driveability issue along with the BLMs. Car seemed to run WORSE for the first three minutes the more I tuned it. For kicks, I bumped the Translator idle up to 10% rich. Runs smoother cold and now BLMs are 129. Not the best way to "fix" a BLM issue, but...

You running the 3" or 3 1/2" MAF??
 
I bumped the Translator idle up to 10% rich. Runs smoother cold and now BLMs are 129. Not the best way to "fix" a BLM issue, but...

Why not? that's exactly the way to do it.
 
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