Hey guys, i've got a wondering for you guys who have tested their TCA's, is the pressure side supposed to hold indefinately after putting pressure into it?

Upon my testing, the vacuum side seems to hold fine with about 8-10 mm hg of vacuum. But when testing the pressure side, it moves fine, but slowly returns to original position after a few seconds, before i release the pressure.

What prompted the testing was that i'm only getting 5 psi on the second turbo. Seems like a PITA to get the TCA out, so i thought i would ask first before replacing it.

Thanks! Dave

 

Bump, i have similar issue, the tca wont hold boost on the boost side. Is this normal????
I did a bunch of searching and wound up here.

 

No. If you apply a controlled source of pressure (Mityvac) it should not leak down.

 

also be sure both actuator lines from the charge pipe off the turbos to the actuators have the original orifice pills inside the lines.

i often times find that people who have changed their vacuum lines neglect the fact that they are supposed to be there and omit them from the system, resulting in erratic/low boost conditions.

see top right side:



they are brass plugs with small drilled port inside the rubber lines, can be removed and swapped to new lines.

 

Thanks guys, so i should replace the TCA??
I am doing a bunch of things to the car right now Including vac lines and siliniods. I have been with out boost for a while and am determined to get the car back to its potential!

 

Yes, it needs replaced. New from Mazda is a little insane (like $800) so buy a low mileage used part from the classifieds.

 

i'm honestly surprised no one has found an alternative part already. mazda is straight out of their mind with the cost of some of these electrical components, $2k for an oil metering pump?! yeah...

but at any rate it's not $800 to correct it, the dual solenoid for precontrol and wastegate is $150 and the single solenoids on the rats nest are $70, new.

 

You won't find alternative parts for these, but fortunately the used pieces are plentiful and cheap.

The OP posted that his TCA won't hold boost. If the TCA fails the leakdown test I mentioned, then the problem is the TCA itself. If he has general boost problems, then it's another situation.

 

i figured he was referring to the solenoids not the actuator itself as the actuators generally don't fail. also hard to believe they are that spendy for a canister with diaphragm, a very simple unit.

 

I remember the day I asked Ray at Malloy for a price on one. We both had a good laugh, especially when I told him they cost $20 used.

I have seen these fail and leak, but not very often.

 

well it's just rubber and it won't last forever, but yes pulling a vacuum on it you should see zero leak for an indefinite amount of time. granted the vacuum pump will likely have a small internal leak before the actuator should.

even $20 is a little steep, considering how many people just bring me boxes of twins you know they are out there just collecting dust. basically cost of a few beers plus shipping, heh. but it's all for the hassle of simply sending it.