Low boost

Diggs24 said:

Try this with vcds. Find these 3 items to log:

acknowledgement 2.144V
for lo 3.862V
for up 0.8672V

image by Diggs24, on Flickr


That is the upper and lower positions for the WG (basically fully open and close) and resting position. Have those shown and run this test POSITION TEST OF END STOPS:

video
https://www.flickr.com/photos/98218625@N04/27404871898/

Ignore the values I am looking at as they aren't the upper and lower (and it fails the test too).

Actually, if you look at acknowledgement while it runs the test you can see my upper and lower before I got the voltage right (3.398 and 0.54ish). Those do not pass. As you can see your lower is 3.62V. That is not low enough. Should be closer to 3.8ish I think.

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Blueballs said:

So tonight I detached my downpipe from the turbo and hooked up my VCDS software. I went into the measuring blocks and did exactly what you showed in your video. I pressed go, and went to look to see if the wastegate moved the flap in and out. It did. I double checked the nuts on the rod on the actuator and tightened them down a bit more. Everything passed according to VCDS. Wastegate is working, but still no boost. I’m really thinking the turbo is toast due to the tuning. I don’t see why it keeps throwing an EPC light for wastegate actuator when it passes all the tests.


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Twist said:

What has your tuner said about it?

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jerodbroten said:

So, I've been following this and doing everything that everyone has said. Like you blueballs, everything is the same. I'm writing EQT and inquiring about a new turbo. I think it's a flaw in the turbo.

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jerodbroten said:

So, I've been following this and doing everything that everyone has said. Like you blueballs, everything is the same. I'm writing EQT and inquiring about a new turbo. I think it's a flaw in the turbo.

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jerodbroten said:

How far into your tuning process are you both?

I'm on my third revision (so maybe 3 or 4 weeks), but the EPC started after the install. I adjusted the acuator to 3.8 and thought it fixed my issue. That's when I started logging for my revisions, however it didn't last long and the EPC returned.

How many miles ago did this issue start happening? ^^^^^


Did anything else change around that time with the tune or hardware?

The only thing that changed was the turbo and tune. I was REVO stage 3, stacking JB4 and running WMI on my IS38. I switched to COBB AP to install the EQT tune and took the WMI off.



I would suggest uninstalling ALL of the piping going to or from the turbo, including all the intercooler hoses. Once they are off, reinstall and make sure all is buttoned up nicely.

I've looked over everything many times; checked connections, adjusted/replaced the actuator, made sure all hoses were clamped tight, ect.



Also suggest putting the stock DV back in place for troubleshooting.

Been using the stock DV since my IS38, even took it off and oiled the spring just to make sure.


I would test with just the JB4 as Diggs said and separately test with the jb4 removed.

I'm currently not using the JB4, only the ECU tune as requested by ED.

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MadMen said:

Dumb question, but gotta ask - did you plug the meth bung, and make sure the plug is still in the pipe? The PUT sensor is before the bung, so it will read full boost, but the boost is escaping before making it to the manifold. Just a theory of course, but worth checking.

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Blueballs said:

What do you mean by the meth bung? What pipe? I’m not using meth. Just regular 91oct.


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