Which is defective, this part or my brain?

I bought a box of vacuum tees and couplers from O'AutoAdvance a while back and used the above bit to attempt to split a vacuum/boost signal from the Megasquirt MAP vac line to the surge/blow-off valve. After going through three different valves and doing all sorts of elaborate testing of the valves themselves, I kind of accidentally hooked up a boost gauge to the line that was going to the surge valve and noticed that when I put it under pressure with a compressor, Megasquirt showed boost pressure but the gauge didn't. Turns out that the little downward barb on this splitter is actually not tied in to the other two barbs in any way shape or form. There's no check valve, and if you hold it up to the light and look down the barrel, as it were, the inside is totally smooth as though they molded that lower barb on but never drilled it out.

My assumption here is that this little bit, made with love and lead in the PRC, is completely defective and no one would ever build something that looks like a vacuum tee where the "tee" part was totally blocked off. But, then, I'm kind of self-taught here which means I have huge gaping holes in my mechanical knowledge and the whole vacuum line system sort of falls into one of those holes. They wouldn't have actually done that on purpose, would they? I mean, other than "hey, let's play joke on capitalist pig"?

And if my assumption about the function of that piece of plastic is correct, consider this a rant on how crazy it makes me when a brand-new half-cent part sends me down a months-long expensive parts-a-thon troubleshooting session.

Definitely an error in manufacturing, just drill it out.

There are things you could expect in poor-quality parts from China...that is not one of them. You should be able to assume that tubes and pipes have, you know, holes in them!

81cpcamaro wrote: Definitely an error in manufacturing, just drill it out.

This, can't imagine what a blocked-off pipe could be for, unless it's supposed to be a m-m adapter with a free plug attached

Yeah, I couldn't imagine any reason to install a vacuum coupler with an attached spare vacuum line holder. It's always said that you should never make the assumption that a part isn't broken just because it's brand-new, but I'm with you: You should be able to assume that tubes and pipes are tubes and pipes. Thanks for the sanity check.

wow... I would have never looked for that

Hey, you got extra bonus plastic for the same price as a regular part

It's CDM, yo.

Thanks for giving us one more thing to check BEFORE we install one of those.

As a footnote to the story, after I drilled it out, I found the box that it came in to check the rest of them. According to the label, there's a wide assortment of junctions, adapters, and tees. There are supposed to be 5 of those y connectors in the package. Apparently there were actually six, because there were five left in the box, all of which were manufactured correctly. This car is just a bad luck magnet.

In reply to wae:

So, no more "fun" boost spikes at RallyX this year?

Well, I don't think it was causing any spikes -- those are all courtesy of that one little hot-side pipe coupler that keeps coming apart on me. But this should reduce the possibility of the compressor blades coming apart and filling the cylinders with exotic sandblasting material.