Jeff N.

Trying to sort the problem listed here.

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/442682-the-10-000th-my-car-stumbles-thread.html

I'm now thinking I have wastegate issues as I have the same run problem when the boost is set to 10 lbs or 15 lbs. As it approachs the max amount set with the MBC, the car begins to slightly stutter and loose power.

Archive search shows no real problems with the Tials (unless you count all the backward hose installations) Tial site does show rebuild parts.

Could I have a diaphram sealing problem? Hmmm.

Darwantae951

There really isn't much inside a Tial. Diaphragms and a spring mainly. I'm sure if you contact them they can get you replacement parts (my instructions said that a special valve for running leaded gas could be ordered, so I assume you can order stuff directly from them).

Remember that anything can malfunction.

Ian Carr

Strongly doubt it, tials are pretty bullet proof. I would try and find another problem.

Jeff N.

Hi Ian - yes, the archive history suggests the same.

Any ideas as to why my problem "moves" as a change the wastegate relief pressure? That's the strange part, no?

MitchB

Are you absolutely SURE you have the hoses and / or boost controller hooked up correctly?

Jeff N.

Yes. It's worked fine for 2 years until now and I haven't touched the hoses.

ehall

Are you using the KLR?

RR944T

Once I had one with a damaged diaphragm .

ehall

how old/used was it? That's awfully unusual.

Jeff N.

RR944t:

What were the symptoms and how did you test to determine it was a problem? Thank you

RR944T

After if was installed and setup with an EBC, we could not control boost pressure, at first we thought that the lines were installed backwards, but after swapping them back, we had the same results. I disconnected the the EBC and installed a **** style MBC and put the boost line on the side of the wastegate and had the same results, so I ended up sending the unit back to the vendor, once we got the new one unit the problem was solved.

Keithr726

Yes they can have problems, just not to likely. The spring could be getting weak causing as weird reaction or the diaphragm is torn and causing the same. Not too difficult to take apart and test with a pump.

azmi951

If you have used a lot of leaded fuel it attacks the anti friction coating on the valve stem unless you have the valve for leaded fuel.

Without the coating the valve galls in the housing and sticks. They do have 2 types of valves. One for unleaded (cheaper) and one for leaded. There is not a big cost difference but since the 38mm is the "budget" wastegate most are ordered with the cheaper unleaded coating.

Wormhole

I had the nut that attaches the diaphragm to the housing back out. Caused a Vac leak and increased psi, but it did not cause the symptoms you are describing.
Yours sounds electrical.

ehall

lol. That's what I told him.