!G DSM BOV acting funny, causing CE light

Years ago when this car was running before, I had installed a 1G DSM BOV onto it. Everything worked, it blew off and sounded good. I can't remember but I think I had it T'd off of the main vac source on the front of the intake manifold.



Now, when I install this valve and start up the car, the valve partially opens and draws in air. The check engine light comes on. Did the spring somehow weaken? Shouldn't it be shut under idle and cruise vacuum until you close the throttle plate between shifts and see hard vacuum?

With the BOV pipe section removed and a straight piece of pipe from the intercooler to the throttle body, everything works right and no CE light.

???

I'm flanged for a DSM BOV, so I'd just get another one. I just want to better understand where it *should* go or more importantly where NOT to route the hose, and how it *typically* works. That way I can better jusdge the condition of my own BOV and be more motivated to replace it with another one.

I'm gonna take it off for now, the car acts normal and no CE light with it removed, just running a straight piece o' pipe from IC to TB.

[xrattiracer]

Those valves will open at about 14 in of vacuum, which most engines will pull at idle, and certainly will pull on decel. this isnt necessarily a bad thing, but you might consider some kinda filter for it if the air in your area is consistently dusty (dirt road, etc).
It seems like you have it hooked up right, from your description.
Why it would cause the ecu to turn on cel i dont know, have you tried to pull codes to see why it is getting set?

[cky]

i used to own a dsm and they open at 17 in hg. and you can crush them alittle to make them open later. idealy at 20 or 21 in hg.

[turbovanman]

It will pull a little vacuum at idle. I crushed mine slightly and its much better but I still run a small filter on it.

This will not affect your check engine light, you don't have a MAF system. Theres some other reason your light is on. Pull the codes and let us know.

[GLHNSLHT2]

crushing it slows it's response time which is what you want. Having it open at idle is a good thing. Just put a filter on it. K&N 62-1440 works great. $16. If ya need it to hold over 20psi then mod it like www.thedodgegarage shows.

Like others have said it shouldn't cause the CE light to come on.

[lametec]

Only reason I can think of for the CE light to come on is that it's causing issues with the MAP sensor signal. You didn't by any chance tee the vacuum hose into the MAP line, or from the same source as the MAP line?

[Harvii]

I'd recommend pulling the vacume for the BOV from the throttle body.

Harv

[turbovanman]

Quote:

Originally Posted by lametec Only reason I can think of for the CE light to come on is that it's causing issues with the MAP sensor signal. You didn't by any chance tee the vacuum hose into the MAP line, or from the same source as the MAP line?

Good point, didn't think of that. Maybe the diaphram inside the BOV is ruptured that would cause your problems and the rough running, check engine light!

Yeah I fixed the CE light prob, but you know what I think it's a good idea to move the T to the throttle body.

I want to redo the vac lines on this thing. I don't need a BCS anymore with the MBC on, so I may redo the fourway and clean it up.

[ShelbyGLHS592]

I run the vacuum line for the BOV to the brake booster.