Plain Jane OEM nothing to see here rebuild

[RETed]

Originally Posted by JustJeff

I haven't been able to get my electric boost gauge wired correctly. Rather than fighting my subpar wiring I bought a cheap mechanical boost gauge as a temp fix and laid it on the windshield so I can see it's readings. What I found is that I have zero vacuum. I've got my MBC set for zero boost. If I raise my RPMs up to 3k I can see a small nudge in the boost. BUT I never see any vacuum at all.

If you're talking about the MIDDLE fitting on the front of the throttle body...
*This is normal.*
That fitting leads to PRE throttle body, so it will never see vacuum.
It will see boost when the turbo kicks in.

You will only see vacuum if you find a fitting POST throttle body.
The fittings either above or below both go to POST throttle body.

I took the UIM off to investigate. What I'm wondering is what happens if I put the plastic gasket between the throttle body and UIM on backwards? I believe I put it in correctly, but what if? Also, I find it strange that there isn't any gasket or o-ring to seal this. Should I put a thin coat of RTV on it to help seal?

Mazda doesn't do this from the factory.
Although there is a *slight* vacuum leak from this area, I think trying to seal everything with a liquid sealer (i.e. silicone RTV) is more headaches that this is worth.
Specifically, you might end up plugging those little holes for the fittings with RTV...
(Don't ask me how I know this...)

I have it off now, but I had it mounted with this end toward the TB. The port matches the ports on the TB.

If you have this black phenolic spacer on backwards, NONE of the fittings would work.

The other end facing the UIM. The ports match the 3 on each side of the UIM.

I had the intakes powdercoated. To make sure none of the vacuum niples got clogged I took a hose and put it on each nipple and blew through it. They were all free and open. BUT I found this when I blew through the middle front nipple.

Oil...so I"m guessing my vacuum routing is wrong. But it also seems like it could have been wrong for some time now. Maybe I'm wrong but should my TB be this coated in oil?

Middle nipple on the UIM corresponds with the middle steel hose on the spider.

That steel hose eventually ends up at the purge control valve

One of the two hoses coming off the purge control valve goes to the middle iron

The other I have feeding back into the spider here

And then comes back to the bottom steel hose and I have that feeding back into the bottom nipple on the UIM

What have I done wrong?

See above - you did nothing wrong.
That middle fitting is for the emissions system which leads to the purge valve.
It looks like you have everything routed right.
Mazda designed some complicated vacuum control system to suck out vapors from the "crankcase" to be pulled from two different areas of the oil filler pipe depending if the engine was in vacuum or under load with the turbo spooling.
I think it's kinda stupid, but Mazda spent a lot of money figuring all of this out.

As for the gunk on the backside of the throttle plates...
I think yours is a Kouki 13BT?
If so, this is more so...
This is due to reversion of the intake ports.
It's exhaust gases (and other junk) being blown up from the intake ports from inside the engine and emissions.
On Kouki 13BT engines, the secondary ports open up first prior to the primary ports.
This fact allows stuff to blow back up the intact tract and tends to coat the insides of the intake manifolds and backside of the throttle plates.
Again, it's normal.


-Ted