j2b4o

Was changing the temp sensor for the gauge and I noticed that the BVSV had the top vacuum nipple broken off with super glue all around it. It must have broken on the previous owner and he tried to glue fix it. So I ordered a new one but it's going to take a few days so I ran the manifold line directly to the vsv or egr or whatever it connects to (forget and don't feel like looking it up again). If I understand correctly this should mean that the egr is always circulating?? Or if it controlls fuel at idle it is either keeping a rich mixture all te time?? There was a bunch of mixed info found from searching. anyone with a real strong grasp of how this thing functions?? Is it ok to keep it like this for a few days till the new one gets here??

91LS400vgb

The BVSV measures the temperature of the coolant and will prevent the EGR from working by venting the vacuum (intended for the EGR valve) to the atmosphere until the coolant has reached a certain temperature.

j2b4o

Replace the valve sometime last week and the car seems to not run as hard at WOT as it did with the vacuum vented all the time. Any ideas? Is it Normal because the egr is now circulating? It's not a huge difference but WOT was more pronounced with it disabled.

91LS400vgb

If the BVSV is functioning properly, then once the engine has warmed up, the EGR should open to allow exhaust gases into the intake during periods of low to moderate acceleration or cruising. The EGR should not open during idle or heavy acceleration like WOT. Lexus uses a Vacuum Switching Valve (VSV) - not to be confused with the BVSV - to make sure EGR doesn't open at these times. The VSV is just a solenoid switch that is operated by the ECM. When the ECM doesn't want the EGR to operate, it activates the VSV to vent the vacuum to the atmosphere. The VSV is a common failure point but can easily be tested.

j2b4o

Can u tell me the short version of how to test it?? Like that OHM or vacuum range or whatever it's measured in? Thanks!
Also it's only anecdotal now because I haven't actually measured the MPG yet but I do drive the same commute all the time and I'm fairly sure that I was getting more mpg with it disabled.
The car is 22yrs old so it could be O2 sensors dying also.

91LS400vgb

j2b4o - look at page 14 of the following link for how to test the VSV
http://www.motor.com/magazine/pdfs/092009_04.pdf

j2b4o

Thanks! That's a good read and good to have on hand in general!
I'm doing the SR bushings tomorow anyway so I'll definitely take a good look at all the egr related items.

j2b4o

The whole vacuum egr system checked out fine. I replaced my fuel pump today and the car has much more pep in its step. I'm assuming it was just the worn pump causing inconsistent WOT responce, seems to be all better now.

Treezy

Hello to all. I noticed that the top nipple on my BVSV has broken off also. I'm going to go ahead an order another one & it appears to just screw into place, however I noticed some blue stuff around the threads of the BVSV. Is there anything special that needs to be done when replacing the BVSV? Thanks in Advance for any & all assistance w/ this matter.

RA40

iTrader: (6)

Excellent...THANKS!