Boost issue and other oddities

HOFF

Greenie N00B Member
Hello,

as mentioned in my introduction I have a boost issue with my Mazdaspeed 3.

Modifications
-2.5 swap including the timing

Replacements
-replaced intake cam to fix P0012
-replaced aftermarket cold-air intake for stock
-repalced old worn turbo with Rockauto GPD k4 turbo

Symptoms
-low boost
--1st/2nd gear 5psi
--3rd/4th/5th gear ~8-10psi
--6th gear full 15psi
-WOT bucks at 5000 RPM in 1st/2nd/3rd will not redline, wont buck when creeping up to redline
-rich in 1st/2nd gear
-O2 and MAF go out of spec near redline

Wierd symptoms- My father got ahold of an Autel scanner and recorded these parameters, hes never uesed them for diagnosis thought.
-Fuel injection amount[mg/cylinder] and engine load is out of spec

Diagnotics
-checked all clamps and hoses
-checked cat for any blockage
-did boost test plugging the intake with a plug and used pressure regulator.
(all this did was inflate the intake piping and all I could hear was the head filling with air. I may need to come back/ find a better way of doing this)

Me and my father, who is an ASE master tech have been trying to hunt this issue down, but hes not familliar with this car or engine. Would love to hear y'alls thoughts on this. I probably need to find a better way of doing the boost test. During the 2.5 swap the pipe leading from the head to the intake got snapped in half. we quickly put hosing over it. This is probably causing un metered air to come into the system. and thats all I could hear leaking when I did the boost test.

thank you.
 
So you know you have a leak in the intake tract and are wondering why your car exhibits signs of a leak in the intake tract? Fix the intake first
 
Easter Bunny said:
So you know you have a leak in the intake tract and are wondering why your car exhibits signs of a leak in the intake tract? Fix the intake first
Click to expand...
I belive that is not the issue, the breather for the head is hooked up brefore the turbo near the airbox . if there was a leak it would have on the turbo to EBC to intercooler to intake manifold. Forgive my ignorance, but could you explain your reasoning?
 
Anything between the MAF and primary O2 sensor is an issue. Needs to be a closed loop between the two
 
HOFF said:
Hello,

as mentioned in my introduction I have a boost issue with my Mazdaspeed 3.

Modifications
-2.5 swap including the timing

Replacements
-replaced intake cam to fix P0012
-replaced aftermarket cold-air intake for stock
-repalced old worn turbo with Rockauto GPD k4 turbo

Symptoms
-low boost
--1st/2nd gear 5psi
--3rd/4th/5th gear ~8-10psi
--6th gear full 15psi
-WOT bucks at 5000 RPM in 1st/2nd/3rd will not redline, wont buck when creeping up to redline
-rich in 1st/2nd gear
-O2 and MAF go out of spec near redline

Wierd symptoms- My father got ahold of an Autel scanner and recorded these parameters, hes never uesed them for diagnosis thought.
-Fuel injection amount[mg/cylinder] and engine load is out of spec

Diagnotics
-checked all clamps and hoses
-checked cat for any blockage
-did boost test plugging the intake with a plug and used pressure regulator.
(all this did was inflate the intake piping and all I could hear was the head filling with air. I may need to come back/ find a better way of doing this)

Me and my father, who is an ASE master tech have been trying to hunt this issue down, but hes not familliar with this car or engine. Would love to hear y'alls thoughts on this. I probably need to find a better way of doing the boost test. During the 2.5 swap the pipe leading from the head to the intake got snapped in half. we quickly put hosing over it. This is probably causing un metered air to come into the system. and thats all I could hear leaking when I did the boost test.

thank you.
Click to expand...
 
As mentioned above, you seem to know you have un-metered air entering the system. That is an issue that can be easily resolved.
If the pipe broke you can use a regular hose from the head to the intake, put clamps on it to make sure it is sealed.
Even though it seems sealed and good to go at idle, at high RPM and Load things change, especially if the PCV system is not in the best shape or dirty. This can make even a small leak at idle a large leak under load.
The more un-metered air entering the system, the more the inputs to the ECU are skewed the more the ECU adjusts the wrong way.

Please tell us how you pulled the boost data?
Maybe used the provided TROUBLESHOOTING SHEET at the top of this forum
What are your current boost targets by Gear, RPM and Load?
Can you see/record Boost by RPM? If so what is it?
What is your AFR while doing these pulls? By RPM, Load and Boost?
What is your HPFP Pressure, actual by RPM and Boost?
what is the Knock retard reading while doing these pulls?
Are you absolutely sure that when you replaced the intake cam, you got the timing correct?
Are you for Imprint sure?
Did you use new friction washers on the Intake cam? (assuming that is the only one you loosened up) if you loosened the Crank and or the Exhaust cam, they needed new friction washers as well.
If I were to throw out a Wild Ass Guess, about the boost issue, I would say that your Boost controller is not doing it's job (maybe isn't hooked up correctly or plugged in all the way).
I will hazard one more Wild Ass Guess, The Bucking could be fuel cut due to knock
You mention some things are out of spec, but you don't say how much or which way, and that is important, please provide the details for these readings.

Please keep us updated on how this works out
Thanks
 
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