Bladed-vaults

Ok so I have exhausted every option I can think of before posting.
My car developed a overboost issue about 2 weeks ago. Nothing changed up until then and the car turned off fine, started the next morning and getting on the highway problem appeared.
I have checked/replaced lines to wastegate/boost controller. I have checked double and Triple checked proper routing.
Checked all other vac lines. Reading healthy vac at idle.

The WG is. Tail f38 and the ebc is blitz sbID..
I can put the controller on any setting any amount of boost and it will still build boost and proceed to overboost. I can even set the controller to 0 and it will boost.

What's my next step in trying to hunt this down? I feel like the fact that even if I set boost to 0 it builds boost, that this is an issue with the controller??

refresh951

Open up both ports to atmosphere on the WG and you should run spring pressure (probably 0.9 bar). This will let you know if it is the EBC (most likely IMO).

Bladed-vaults

Still boosting. Am I to assume it's an issue with the wastegate at this point? Have a friend coming in with a manual controller to throw in just to see. This won't be until tomorrow

refresh951

Most likely an issue with the WG, sounds like the valve may be stuck.

Bladed-vaults

So we swapped in the MBC. Now if I put it to 0psi. It works. But if I put anything above 0-5 it still over boosts.

JacRyann

Might have vacuum/pressure hose connected wrong from the boost-solenoid or MBC (pressure-regulator has different connections than check-valve type).

Post a diagram of how you have wastegate, boost-solenoid and hoses connected.

JacRyann

Exhaust pressure is not directly related to boost-pressure. The spring-pressure is based upon surface-area of diaphragm when fed intake-manifold pressure.

A Tial with 0.9psi (intake) spring will actually require 30-40psi of exhaust-pressure to open without any pressure in the diaphragm.

Bladed-vaults

its identical to the lindsey diagram with their MBC again i checked and rechecked.
This is some knockoff controller but its the same style as the lindsey one.

works fine on the VW it came out of.

Im ordering a new diaphram and springset for the Tial. If anything it will be nice to rebuild it i have no idea how long this WG has been in the car.

fejjj

The Tial vac lines are connected OPPOSITE of the LR Dual WG as shown in the LR diagram.

If you have them connected on your Tial the wrong way, the car will immediately over boost.

Bladed-vaults

switched em this morning before work just to see. no change. Im weighing in on the WG being in need of rebuild more and more

Black51

Have you pressure tested the intake? That will for sure rule out any leaks. I recently was getting massive overboosting (~30psi), until I realized the vacuum line from the boost pipe to the WG got pinched and was severed. I had no boost control! It happens.

Bladed-vaults

Replaced everything inside the WG and put new fittings on and everything seems to be working now. Holds boost and no more overboost...

Thanks for all the suggestions every threw at me!