08 Donor, losing boost on turbo randomly. limp mode. Help

Lando217

Lando217

Well-Known Member
Hi everyone, it's been a while since i have been active on this forum. i have kit #125 and finished it sometime early last year. since than iv used it many times over the past year with a problem. I haven't had much time lately to get into it because I started a new home build and that took most of my free time. Now that I have more time, I am reaching out to see if anyone has had my same problem or maybe can help me.

So randomly when driving the car, it decides to go into "limp mode" and cuts off all my boost. I am still able to accelerate and get up to speed but with engine power only.
I can turn off the car and turn it back on mid drive and then i have boost again. There is no rhyme or pattern when this happens. some days it happens once on a 2-hour drive, sometimes it happens 5-8 times. It might seem like it happens more when I am light throttling the gas pedal when cruising but not 100% consistence.

I was thinking maybe some loose wiring? but that does not explain being able to turn off and on to fix the problem?
maybe there a sensor to monitor the waste gate and its faulty leaving it open? (haven't looking into this)
it has new MAF sensor, but I don't know if those effects it.
I haven't checked my grounds lately, maybe something losing power for a split second?
i am boosting around 19-20psi. I don't know if that will affect it because it done not really happen when I drive the car hard.


I was able to drive my donor for a few days before the tear down and never noticed this before the build.

Any help is appreciated!
 
Lando217

Lando217

Well-Known Member
Gtstorey said:
Have you checked for DTC's?
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Current faults:
P0449- evap vent valve
P0452- evap pressure sensor

pending faults:
P0443- evap purge control valve
P0650 Malfuctioning indicator lamp.
P2127- throttle pedal position sensor/switch E circuit low input.
I am assuming the evap codes are common with all kits cars?





I used to have a problem with gas pedal going out on me. Since then I have putt a new pedal with sensor and ran and new 5v line from ECM to sensor cause I felt like the one in the harness was not contacting right. Haven’t had the problem with the pedal anymore.
 
G

Gtstorey

Goblin Guru
Did you clear the code after replacing the pedal sensor?

Either way, clear it and see if it comes back again. If so that is the first place to start.

The evap codes are ok.

Did you mess with the MIL to keep it from coming on?
 
Lando217

Lando217

Well-Known Member
Gtstorey said:
Did you clear the code after replacing the pedal sensor?

Either way, clear it and see if it comes back again. If so that is the first place to start.

The evap codes are ok.

Did you mess with the MIL to keep it from coming on?
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I will clear the codes and give that a try.
Thinking about it now. Iv read the codes many times over the past years and The MIL was not always there. This is a newer code. I have not done anything (on purpose) to mess with the indicator lamp. Thank you!
 
Lando217

Lando217

Well-Known Member
Gtstorey said:
Forgot to ask if the donor car was modified and has it been tuned?
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It was stock from I saw and was told. Zzp reflashed a new ecu when I thought the old one had a problem…
With the new ecu from zzp. They did add the small tune for first gear and boost. I can’t remember what it does but something along the lines of small ramp up on boost to prevent wheel spin in stock cars.
 
S

Scott #321

Well-Known Member
My 09 LNF will due this occasionally due to an overboost condition. I don't believe that the mil condition can be tuned out of the PCM though only to ignore and not turn on the light.
 
Lando217

Lando217

Well-Known Member
Scott #321 said:
My 09 LNF will due this occasionally due to an overboost condition. I don't believe that the mil condition can be tuned out of the PCM though only to ignore and not turn on the light.
Click to expand...
Maybe il turn down boost a little. I think it peaks at 20psi. Stock should be around 16?
 
Lando217

Lando217

Well-Known Member
Gtstorey said:
How where you going to turn down the boost? Do you have a non-oem wastegate?
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Please correct me if I am wrong, I know there is a procedure with adjusting the stock waste gate arm tread and nut. Your suppose to close the waste gate then hand tighten the nut where the gate stops, then 3 complete rotations of the nut to apply pressure on the gate. Then tighten the back up nut. In theory setting back the waste gate nut system so there is minimal bypass into the exhaust, thus creating less boost?
 
G

Gtstorey

Goblin Guru
I've never heard of anyone trying to use this to reduce boost, but I guess it's possible to do it this way. The normal way of doing it would be to adjust the settings in the tune by adjusting the Waste Gate Duty Cycle and the Desired Air Load table.
 
Lando217

Lando217

Well-Known Member
Gtstorey said:
I've never heard of anyone trying to use this to reduce boost, but I guess it's possible to do it this way. The normal way of doing it would be to adjust the settings in the tune by adjusting the Waste Gate Duty Cycle and the Desired Air Load table.
Click to expand...
Sooo since I am boosting around 20-21 psi and stock is said to be 15-17 psi. Maybe I am over boosting and seeing up some warnings? Maybe zzp adjusted the boost when I got purchased an ecu.
But it does seem like I would need HPtuners lol
Thank you for all the answers you have given me!
 
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