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weird boost issue

cypher0117

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cypher0117 Rising Star

cypher0117

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Recently I've been having really weird boost issues. Sometimes I only get 8lbs, other times I get 20 and anywhere between the two values. Most of the time I'm only getting 16 even though I'm tuned for 18. I've been looking for boost leaks but I cannot find any. I've pressurized my inlet/intake with my air compressor and hear no hissing anywhere. I'm not entirely sure how high I got the air pressure, but my regulator was set to 20lbs and my leak tester actually blew out of my intake and went across the garage followed by air rushing for about a second or so. I've manually applied air to my wastegate actuator and that seems to move well. My bpv for all I can tell isn't leaking. My IAM is generally staying at 1 though sometime it does drop and when it does it usually drops to .5 or lower. The only thing I've changed is I now have a 3" exhaust which I wouldn't think would play this oddly with my boost control. My compression was ~140 on all cylinders with a warm motor and no gas.

 

Anyone have any ideas on what to check or have experienced similar problems?

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PtPixel Proficient

PtPixel

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Probably worth checking the EBCS, sounds like a boost control problem.

 

I recall on another thread someone had the same issues with intermittent and random lower peak boost. Turned out their stock BPV was sticking. If you know anyone with a BPV you can borrow to eliminate that then that would a good start.

 

You did say your actuator was working fine, 8psi and 20psi sounds about right for an actuator sticking open and closed though.

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cypher0117 Rising Star

cypher0117

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I did sip tie the lines between the ebcs and the turbo. I tested my actuator by pulling the line from the ebcs and shooting some air in there from my compressor. I could hear the valve moving and see the arm moving. It didn't seem stuck but that was my test.

 

I'll post up a LV tonight when I get home from work

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iNVAR Grand Master

iNVAR

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And what is your tune supposed to be doing? Who tuned it?

 

For now, stop doing pulls until you figure out the problem.

 

Reason you're barely getting boost sometimes is your IAM is below 1 and your map likely has it set to cut boost when you're below 1.

 

You have a good bit of knock where you see the -4 and that needs to be addressed.

 

Your AF trims also appear to be off (more than a 5% diff) which could indicate a boost leak but it'd be strange if that's the case. -7% isn't too bad anyway.

 

If you do decide to do another pull in 3rd, do a reset first, then wait for IAM to go to 1, then do a pull from 2K to redline. Make sure you log it with the parameters I've recommended in the past. Do a quick search for the logging parameters I recommend, I'm in a rush to head out the door so can't find it.

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iNVAR Grand Master

iNVAR

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In the future, log:

A/F Learning #1 (2-byte)** (%)

A/F Sensor #1 (2-byte)** (estimated AFR)

Boost Error* (psi)Engine Load (4-Byte)* (g/rev)

Engine Speed (rpm)

Feedback Knock Correction (1-byte)** (degrees)

Fine Learning Knock Correction (1-byte)** (degrees)

Gear (Calculated)* (position)

IAM (1-byte)** (multiplier)

Ignition Total Timing (degrees)

Intake Air Temperature (F)

Knock Sum* (count)

Manifold Relative Pressure (4-byte)* (psi relative)

Mass Airflow (g/s)

Primary Wastegate Duty Cycle (%)

Target Boost (4-byte)* (psi relative sea level)

Throttle Opening Angle (%)

Turbo Dynamics Integral (4-byte)* (absolute %)

Turbo Dynamics Proportional (4-byte)* (absolute %)

 

Reset again, and log continuously for ALL of your driving. Do not change your driving style. Drive exactly like you have been driving it. We want to catch the moment IAM drops below 1, and also to see how much knocking you're getting all over.

 

If you boost leak tested it, that's great, but your AF trims seem to show a leak. Either that or your MAF sensor is dirty. Have you cleaned it? Remove the sensor from the intake, inspect the O-ring on it for damage, carefully clean the sensor with MAF cleaner ONLY, then put it back.

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cypher0117 Rising Star

cypher0117

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The car was tuned a little over a year ago. Yes I did email shamar, he was thinking boost leak, or fuel delivery issues. I have recently cleaned my maf (within the last 1k miles), but I will do that again.

 

I thought I had this in my original post:

Earlier in the year I got a tank of super water "gas." Bad enough to stall the motor and it didn't start again until I drained the tank and filled up with actual gas. When I did that I swapped out to the DW65c because I had it laying around. I have since gone back to stock fuel pump as I though the dw might have been defective, but it seems as this probably wasn't the issue...

 

So far my IAM has stayed at 1. This weekend I will hopefully have time to look for a boost leak again.

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PtPixel Proficient

PtPixel

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That happens when logging 4-byte parameters the incorrect way, took me a while to figure out why it was doing that with mine. If you can change the logging code then you can fix it (probably can't with AP) otherwise just use non 4-byte parameters.

What you need to do is change this part in the coding for the 4-byte parameters (Boost Error, Target Boost, MRP):

 

databits = 32

 

to:

 

isfloat = 1

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PtPixel Proficient

PtPixel

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Hmmm not sure whats wrong then.

 

Here is my logcfg file which is saved as a .txt, works perfectly for me:

 

type=ssmk

paramname = RPM
paramid = 0x00000E
databits = 16
scalingrpn = x,4,/

paramname = Throttle_Position
paramid = 0x000015
databits = 8
scalingrpn = x,100,*,255,/

paramname = Requested_Torque
paramid = 0xFF7F4C
isfloat = 1
scalingrpn = x

paramname = Ignition_Total_Timing
paramid = 0x000011
databits = 8
scalingrpn = x,128,-,2,/

paramname = MAF_Voltage
paramid = 0x00001D
databits = 8
scalingrpn = x,50,/

paramname = Manifold_Relative_Pressure
paramid = 0x000024
databits = 8
scalingrpn = x,128,-,37,*,255,/

paramname = WGDC
paramid = 0x000030
databits = 8
scalingrpn = x,100,*,255,/

paramname = IAM_(4-byte)*
paramid = 0xFF2C30
isfloat=1
scalingrpn = x

paramname = Engine_Load_(4-Byte)*
paramid = 0xFF6B30
isfloat=1
scalingrpn = x

paramname = Boost_Error*
paramid = 0xFF6428
isfloat=1
scalingrpn = x,0.01933677,*

paramname = A/F_Sensor_#1_(4-byte)*
paramid = 0xFF6C68
isfloat=1
scalingrpn = x,14.7,*

paramname = Knock_Sum*
paramid = 0xFF7C18
databits = 8
scalingrpn = x

;-------------triggers---------------
paramname = defogger_sw
paramid = 0x64
databits = 1
offsetbits = 5
isvisible = 0

conditionrpn = defogger_sw,1,==,Throttle,51,>=,||
action = start

conditionrpn = defogger_sw,0,==,Throttle,49,<=,&&
action = stop

 

^parameter IDs might be different for different ECUs.

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PtPixel Proficient

PtPixel

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Oh, are you using stand alone logging? If so there might be another file that the tactrix actually uses for logging, make sure that every time you change your logcfg file that you delete all other files on the SD card.

 

When your tactrix starts logging for the first time is configures how to log using the logcfg.txt file and saves this as a permanent logging file and will not reference the original logcfg.txt file again unless the permanent logging file is deleted. Then it has to remake the permanent file again.

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