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2006 Mazdaspeed6
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Discussion Starter · #1 · (Edited)
So, I have been having an issue with my car ONLY under medium to heavy load, I can build boost slowly but if I get on it the car doesn't like it - at all. I have searched, I have tried maintenance things like new spark plugs, gapping correctly, cleaning sensors, looking for any leaks post MAF, checking connections etc. but still have the same issue. Most of the threads or google searches I've read have issues where the persons car will act up at WOT but only for a moment, and continue to redline no problem, this is not the case for me - it progresses and then overboosts, so I back off completely whenever I feel it start.

I want to note too that my external wastegate spring setup should only be around 14psi, but the car is building way past that.

I have removed, cleaned, and reinstalled the EWG confirming that it isn't stuck closed - if it comes to it I'll remove it again and pressure check the spring rate and remove one of the springs if necessary to just gain stability at a lower PSI for now. I also have reviewed over and over that my Cobb 3 port EBCS is set up correctly with hoses going to the right places from the right ports - the only concern I have with it is whoever installed it originally must have no known that it was plug and play - and started cutting before realizing - so one wire is routed through from connector to connector and the other is just connected wire to wire, the connection is solid but its an ugly setup which I'll eventually cut and install new connectors.


I have suspected possible leaky or clogged injectors, I can produce a CEL IF I hold out during the event but again typically back off because I don't want to pay for a new engine build anytime soon. Codes I have achieved during the issue are typically misfire codes (was, until today, usually cyl 4 but today got cyl 1) and "overboost condition".

I have datalogged, I'll post the numbers below, I don't know TONS about the tuning process or what I should see, but the only thing that seems to happen in correspondence is spark advance dropping tremendously, I know typically it lowers under load but wasn't sure by how much. On the second pull I got a flashing CEL that turned solid for a misfire on cylinder 1, and as you can see I'm shooting way past the boost numbers that my EWG should be keeping me around, but definitely hear the WG (though it sounds choppy/shuttery - though everything does when it starts to happen). The car starts stumbling, stuttering, but again if I let off and drive less spirited it's COMPLETELY fine, it is only under moderate to heavy load that this happens.

I am protuned, with a dramatuned basemap+maf cal, running a built engine and gt3076 w/ tial EWG and Cobb 3 port EBCS, all other mods are in my build thread but I can add everything here if easier or if anything else may be relevant.

Here is the log, there are two pulls - in each I made sure to be not overloading the car I was in second or third at over 3000 rpms before increasing throttle.

IF there is any insight, or ideas people can come up with I really appreciate it. I really want to start completely enjoying the car and cant get any map revisions and work towards blended fuel until I can go WOT for logs, and I am no where near being able to do that right now.

(bolt + italic are the "pulls", tried to format it to make it easier to read but that didn't copy across..)


Time (sec)Accel. Pedal Pos. (%)Actual AFR (AFR)Boost (psi)Boost Air Temp. (F)Calculated Load (Load)HPFP Act. Press. (psi)Inj. Duty Cycle (%)Intake Temp. (F)Knock Retard (°)Long Term FT (%)MAF Voltage (V)RPM (RPM)Spark Adv. (°)Throttle Position (%)Vehicle Speed (mph)Wastegate Duty (%)

3.3202214.70-3.881090.60168411.37970.001.402.34373934.00203200
3.4182314.85-3.661090.62176911.78970.001.402.36376033.50213200
3.5182514.85-3.231090.65176112.39970.001.402.41379432.00213200
3.6182614.70-2.871090.68174213.25970.001.402.43383630.00223200
3.7222714.85-2.231080.70178513.89970.001.402.52387228.50243200
3.8182714.85-1.581080.77178415.53970.001.402.56392221.00243300
3.9252714.55-1.651080.77177415.52970.001.402.56396021.00233300
4.0242714.55-1.371080.78177715.87970.001.402.61400821.00243400
4.1252714.55-0.721080.84176917.64970.001.402.66405819.00263400
4.2262814.850.281080.91182019.69970.00-0.162.75411417.50273400
4.3262813.960.641080.97179422.05970.00-0.162.81417616.50273500
4.4222713.670.641080.96179422.48970.00-0.162.80422516.50253600
4.5212713.670.421080.94177722.14970.00-0.162.79426916.50243600
4.6202713.820.571080.96181622.23970.00-0.162.82434317.00243700
4.7232713.820.781080.98179423.42970.00-0.162.86439116.50243700
4.8252713.820.861080.98178523.34970.00-0.162.87445417.00243700
4.9182713.821.361061.04177425.66970.00-0.162.95452916.50243800
5.0282713.521.571061.04177425.12970.00-0.162.95452916.50243800
5.1222513.671.291061.01181326.01970.00-0.162.94459017.50243900
5.2172513.521.571061.01180625.93970.00-0.162.95463017.50233900
5.3222713.823.301061.00179127.95970.00-0.163.07471118.50244000
5.4223213.386.601061.12183840.72972.45-0.163.40480217.50294000
5.5174311.7610.611061.47177857.85972.10-0.163.6749249.50544000
5.6234610.7313.771061.89184170.23972.10-0.163.8649743.00764200
5.7235311.4716.781062.08175673.86971.75-0.163.9349503.50764300
5.8195411.6119.441062.15184182.20971.05-0.164.0151943.50764300
5.9254912.3520.871062.24183887.23971.75-0.164.0452344.00764400
6.0205011.7622.311062.25182988.28991.05-0.164.0953275.00764500
6.1195011.9122.951062.26189395.88993.15-0.164.1054233.00764500
6.2184911.6124.101062.26189397.18994.20-0.164.1254233.00764500
6.3194711.1725.391062.29179495.421005.25-0.164.1354462.00764600
6.4242810.7323.381062.301778100.731005.95-0.164.2555060.00764700
6.526014.26-0.581061.86183062.941020.00-0.163.055547-0.50124700
6.626012.94-9.981060.8213650.001020.00-0.162.89513019.5054700
6.721015.43-11.271060.5613010.001040.00-0.162.44490832.0044800
6.825029.25-11.561060.6313080.001060.001.401.97469625.0044800
6.921029.25-11.631060.4313170.001060.001.401.84449937.0044700
7.022029.25-11.561060.3013200.001080.001.401.42431855.0044700
7.122029.25-11.481060.1113260.001090.00-5.621.21414855.0044700
7.219029.25-11.481060.0513270.001090.003.741.18398755.0044700
7.317029.25-11.481060.0713330.001110.003.741.35383055.0044700
7.422529.25-11.341060.1013272.101110.003.741.43367155.0064700
7.5212429.25-8.401060.2212734.081110.003.741.95382355.00164710
7.6203218.67-0.291080.80152316.951130.001.402.67384021.50354750
7.7223514.110.781080.92177420.141130.001.402.72382416.50434790
7.8224213.381.861081.05180323.011130.00-0.162.8138269.006747130
7.9214313.232.651081.11176725.841130.00-0.162.86388413.006948130
8.0184112.943.731081.16178131.511130.00-0.162.9339069.007448110
8.1223611.764.661081.23181932.831150.00-0.162.99393911.50534880
8.2173611.475.881081.28180334.891150.00-0.163.05398310.50524990
8.3253611.767.101081.36180137.711150.00-0.163.1540179.50534990
8.4193711.768.751081.44184340.661150.00-0.163.2540728.00555090
8.5264011.6110.471081.60176146.101150.00-0.163.3641266.006251120
8.6254611.3212.621081.76185150.221150.00-0.163.5041483.507551120
8.7195511.4714.701081.90175456.471150.00-0.163.6442183.507552110
8.8205611.6117.211082.07186161.361150.00-0.163.6642813.507553120
8.9195612.7918.941082.13180665.131150.00-0.163.6843083.507553120
9.0195612.2020.661082.22185569.541150.00-0.163.7443433.507553110
9.1205712.9421.231082.20184871.491170.00-0.163.7744284.007554100
9.2186112.7921.881082.22183873.251170.00-0.163.7944204.00755490
9.3176212.2022.451082.22184675.191170.00-0.163.8645154.00755580
9.4186312.2023.531082.29176484.651173.85-0.163.8444960.00765670
9.5186312.0523.741082.28178583.701173.85-0.163.8846120.50755660
9.6236212.4924.171082.30178183.021183.50-0.163.8745980.50755750
9.7236112.3524.321082.30177883.991183.15-0.163.9146561.00765850
9.8246111.9124.681082.31176785.061183.15-0.163.9446881.00765840
9.9255911.9125.251082.40187587.451182.80-0.164.0047291.50765830
10.0255012.3525.461082.40187587.711182.45-0.163.9947291.50765810
10.122010.8811.041082.38184184.921182.45-0.162.6147922.00695900
10.217029.25-4.381081.6618610.001180.00-0.162.4047411.50125900
10.325029.25-9.331081.0817520.001200.00-0.161.95442813.0065900
10.426029.25-10.701080.8017610.001200.00-0.162.35423718.0045900
10.530029.25-11.051080.5617770.001220.001.402.21390229.0045900
10.633029.25-11.201080.4217770.001240.001.401.74373937.0045910
10.733029.25-11.201080.1517780.001240.00-5.621.21358555.0045910

If there are other values that would be more appropriate let me know! open to suggestions/advice and if it helps I'll make a short video of driving during the issue so I can try to give a better idea of whats happening.

THANK YOU
 

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Do you know if it goes lean with more acceleration? I’m assuming in those logs you didn’t have the hesitations? What’s the highest boost you’ve seen?

I’m guessing your spark advance goes down in response to knock, since you’re also getting knock retard around that time.

Not sure if this is helpful:

“BTN Turbo say overspeed can be caused by a restriction in the air intake filter or pipe work, or a split or detached air hose, allowing incorrect amounts of air into the turbo.

Other causes include incorrect volume of air in the turbo, a ‘chipped’ or ‘overfuelled’ engine that isn’t to standard specification, worn injectors, loss of signal to the Simple Rotary Electronic Actuator for the wastegate or fitting the incorrect turbo.

To prevent turbo failure caused from overspeed, BTN advise technicians to check that there aren’t any restrictions or leaks in the air intake.
Garages should also ensure that the wastegate or VNT linkage is operating freely and should check the electronic sensors and ECU are operating correctly.”
 

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Discussion Starter · #3 ·
Do you know if it goes lean with more acceleration? I’m assuming in those logs you didn’t have the hesitations? What’s the highest boost you’ve seen?

I’m guessing your spark advance goes down in response to knock, since you’re also getting knock retard around that time.

Not sure if this is helpful:

“BTN Turbo say overspeed can be caused by a restriction in the air intake filter or pipe work, or a split or detached air hose, allowing incorrect amounts of air into the turbo.

Other causes include incorrect volume of air in the turbo, a ‘chipped’ or ‘overfuelled’ engine that isn’t to standard specification, worn injectors, loss of signal to the Simple Rotary Electronic Actuator for the wastegate or fitting the incorrect turbo.

To prevent turbo failure caused from overspeed, BTN advise technicians to check that there aren’t any restrictions or leaks in the air intake.
Garages should also ensure that the wastegate or VNT linkage is operating freely and should check the electronic sensors and ECU are operating correctly.”

Hey, I appreciate the response!

Actually yes, in the log posted the issue occurs, and in the second pull I even landed a misfire code (cylinder 1). Fuel trims look good throughout, and even STFT don't look like they are trying to correct much. I know the knock sensor on these cars is terrible, mine starts acting up to a lot of vibrations and/or sounds under the hood and the fact that my EWG is dumped straight down probably doesnt help. I have checked for splits/leaks/tears throughout the intake, turbo inlet, etc. and made sure all hoses are good and tight too. I' m going to check my MAF sensor and clean it just in hope it does something positive.
 

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For what it’s worth, sometimes leaks aren’t visible. In fact recently I noticed a little bit of oil on the underside of the hose/pipe connecting the intercooler to the throttle body. It wasn’t coming from anywhere else and I could only assume it was being forced out through the hose edges under boost. The hose looked fine and so I replaced the clamps. Same thing. I ended up having to order a replacement hose from Mazda (strangely expensive…!) and that fixed it. Honestly I can barely even tell the difference between the replacement and the original.

It may be worth doing a vacuum (or boost) leak test. Maybe at a good garage with fancy equipment :)
 

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I would do a pressure test. Get a PVC cap and rubber coupler from Home Depot or Lowes the same size as your turbo inlet, drill and pop in a wheel air valve. The valve goes in the top like the pic shows. Its funny, i invented these back in like 99 or 2000 and this fool couldnt even improve on the design much lol. You clamp it to the turbo inlet and can pressurize the entire intake path. If you cant, make sure youre not in between strokes where the intake and exhaust valves are open at the same time.

 

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Discussion Starter · #7 ·
I would do a pressure test. Get a PVC cap and rubber coupler from Home Depot or Lowes the same size as your turbo inlet, drill and pop in a wheel air valve. The valve goes in the top like the pic shows. Its funny, i invented these back in like 99 or 2000 and this fool couldnt even improve on the design much lol. You clamp it to the turbo inlet and can pressurize the entire intake path. If you cant, make sure youre not in between strokes where the intake and exhaust valves are open at the same time.

Got it! So general consensus is most likely a boost leak? And the wastegate issue probably a coincidence that there’s just something wrong with that too? Works for me, I hope that’s all! What’s a safe/good-at-indicating-boost-leaks pressure to run this test at? I’ll be grabbing a pressure regulator at the same time to confirm my EWG spring pressure with a compressor and a couple connectors, plus I’m at Home Depot a ton at the moment anyway for a bathroom renovation I’m in the middle of, so a good excuse to get some car related stuff while I’m there.
thanks!
 

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Well, a vacuum leak is also a boost leak, but its easier to pressurize the intake tract than it is to suck all the air out lol. Plus, if you think you have a leak, you can spray soapy water on it and verify.
 
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