I was playing around under the hood trying to find the source of my mysterious vanishing brake fluid (look for a thread opening near you soon). I don't think I found anything related to that...but I did find some odd things. First and foremost, I noticed a solenoid valve with one broken nipple and no hoses attached to it..just the electrical connection. I'm pretty sure its the purge control solenoid. The interesting thing is that according to the manual, it is supposed to sit between the "catch tank" (under the throttle body) and a check valve which in turn heads into the UIM. Well...someone has completely bypassed the solenoid and check valve, and plugged the catch tank directly to the UIM nipple. Should that worry me? I have no idea what this stuff does.

Next interesting find...there is supposed to be a hose coming off this rather large nipple on the side of my oil fill pipe and connecting to a PCV valve and then to the UIM. The nipple on the oil pipe is not connected to anything, and I can't even find a connection on the UIM for it...although there does appear to be a fairly large short hose coming off that is capped off. I'm wondering if later in '93 they decided they didn't need to connect that, or perhaps it was a CA car thing maybe?

Finally...I had yet another hose and check valve coming off the UIM that had popped off of its connection...not sure how to describe it, but there's a hard pipe with a fork in it...one of the forks had no hose, and this hose was dangling. I'm pretty sure it goes to the pressure chamber in one direction and...something else in the other, damn I don't remember...throttle control maybe? Air control? Dammit! Too many of these things. I'll go find out later and post it.

Anyway, the car seems to run OK with or without this stuff...so is it just emissions crap I don't need? There was a bit of goo around the area, almost like it had come out of the dangling hose maybe? I don't suppose there's any way any of this could lead to disappearing brake fluid??? (I know, sounds like a dumb question, but it has to be going SOMEWHERE..)

jds

 

The checkvalve is making sure you're not pressurizing the "catchcan" and your charcoal canister when the manifold sees positive pressure. The hose is only supposed to suck in gas fumes from the canister when under vaccum.

The solenoid is there to make sure the passage isn't open when the engine is shut off, to prevent gas fumes from accumulating in your manifold and later detonating in your motor when cranking.

That PCV passage was only on the earlier cars. You can read more about it and how to bypass it here

 

Interesting on the PCV thing...I guess my car was "95-ized" at some point...cool.

Thanks for the info regarding the purge control valve. The thing is, I still don't know how necessary it is. All those things that it is supposed to prevent sound pretty bad...is it common practice to not bother with it, or should I wory about replacing that solenoid and check valve?

jds