Over boosting Issue

[robander3]

Hey all,
So I'm really scratching me head on this one. I've been having some issues getting my pressure under control. My target boost is 16 psi and tapering off near redline (similar to COBB OTS Maps). My WGDC is set to 0% across my entire WGDC map, I do allow the waste gate duty boost error comp to have some more freedom. (I followed user Bucker cheat sheet trying to figure it out, Training)

When under pressure I might have a WGDC of about 15-20% at my maximum pressure and sometimes I might have a lower WGDC at the same pressure. I am able to manually move the actuator on the wastegate by pulling (or pushing, I forgot) on it, so that kind of rules out my actuator being seized up. If I were to guess it moved 1/4-1/2 and inch. I am hitting my target pressure for the majority of the time, however it does on occasion over boost and if I don't let off in time I get a fuel cut.

I'm open to any suggestions on how to possibly trouble shoot this, maybe adjust the actuator arm? If so adjust by how much, if anyone knows/educated guess. Would a boost leak cause this, I personally can't see how. I plan on making a tester this weekend. I haven't yet calibrated my mass airflow as its not in cobbs OTS maps, its a mazdaspeed cold air intake.

I did buy this car used and this has always been an issue, I thought it was just the WGDC was messed up, but after trying different maps, modifying maps, and now just having my WGDC at 0%.

I attached the current map I'm running and a data log of mass airflow, Boost, WGDC, AFR, and RPM. (I know I'm running a touch rich under pressure)

Thanks in advance for any help/advice.
-Rob

[Chimmike]

might want to check and see if previous owner put a MBC on the car.

[robander3]

I don't believe so only because when the WGDC is at "normal" levels I over boost to way past 16 psi, upwards into the mid 20s. But I will check non the less.

I've done a lot of forum searching and haven't come across an issue like this, has anyone heard of something like that? Typically the actuator arm is seized somehow but I know mine isn't. Could a air cracked line going to the waste gate cause this?

[dooderek]

I know this is going to sound odd, but whats your tire pressure at?

[6Y MAZDA]

checked all hoses to/from ebcs?

[mituc]

I helped two of my friends fix a similar issue. The problem is in the boost control area but it may have different causes:
1. first guy got it fixed after he replaced his factory EBCS with the one I've sent him (also factory EBCS, I have the GS now);
2. the other guy ended up replacing the entire wastegate actuator (Turbosmart, using only the 11psi spring alone) because the factory actuator was barely moving at about 13-14psi and would not fully open until like 26-29psi.

So whatever the problem is it's in that area. Check the EBCS hoses first, it's the quickest, cheapest and most straight forward thing to do. If the hoses are fine and you still have the problem then you will have to start buying parts.

[robander3]

I'll check the hoses tonight, hopefully that's the issue. Otherwise looks like I'll be pulling the turbo off to further diagnose the issue.

My tire pressure is about 35 psi, why do you ask dooderek?

[MSMS3]

Just check the actuator action with a regulated air source. It should not move before 11 psi, and begin slowly opening as you raise pressure. Mine does not fully extend the rod until about 17-18 psi. Don't use a pressure source higher than 30 psi or you could blow the diaphragm in the actuator.

The advice above seems sound regarding actuator and EBC. You can remove the actuator without removing the entire turbo, but it is a bitch and not really necessary for testing.

If you remove the rod end from the wastegate flapper, the flapper should move freely. If it does not, that could be your problem if it is not opening enough when commanded.

Another thing to do is get some soft wire and wire the actuator rod shut in place so it can't move. Boost should hold at 11 psi.

You are correct that max rod movement is less than 1/2".

I'd be looking for a hair split on the tubing going to and from the EBC. Replacing those lines is cheap.