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-   -   Running on wastegate boost at times? (http://legacygt.com/forums/showthread.php?t=204431)

bg. 03-26-2013 02:38 PM

Running on wastegate boost at times?
 
Looking for some second opinions here,

I just recently had my motor rebuilt with a new block, CP forged pistons, STI nitrated crank and some other parts by a reputable shop.

However, the car also has basic stage 2 parts (DP, EL Header, up-pipe catback and upgraded TMIC) So I have been running the Stage 2 Cobb OTS tune for the time being. At random times (Maybe once every 1000kms) The car will stop hitting full boost, and will run on wastegate boost without throwing any check engine lights (capped out at like10psi max?) Now if I reset the ECU, the car goes back to normal and hits boost no problem, and continues to drive fine for another 1000kms or so. What could be the cause of this? Is this just due to the horrible nature of Cobb's OTS tune? If I have my car pro-tuned for the mods I have, should this fix my problem? Or could there be something wrong with the stock boost solenoid??

Thanks in advance for your input

bg.

KCwagon 03-26-2013 05:38 PM

It's not the "horrible nature" of the Cobb OTS tune. The Cobb ots map is likely one of the kindest and safe OTS tunes out there. It is not, however, meant for a built motor along with your other modifications. Your ecu is protecting the motor. I would get your car pro-tuned ASAP before you experience the "horrible nature" of buying another built motor.

iNVAR 03-26-2013 06:59 PM

Your IAM/DAM is probably dropping to the point where the car goes into failsafe and forces you into WG boost.

1) Stop resetting your ECU. The IAM/DAM dropped for a reason: knock. By resetting the ECU, you are undoing the ECU's protection.

2) Get your car tuned.

wurkenman 03-27-2013 04:19 AM

By all means get rid of the stock BCS with a sling shot, and put on a Grimmspeed EBCS.

KCwagon 03-27-2013 06:20 AM

Quote:

Originally Posted by wurkenman (Post 4361449)
By all means get rid of the stock BCS with a sling shot, and put on a Grimmspeed EBCS.

With a tune....

suds2250 03-27-2013 09:53 AM

Do you know what the wastegate duty cycle is in the base map? I bet the ECU is "forgetting" the cobb realtime map.

KCwagon 03-27-2013 08:10 PM

Quote:

Originally Posted by suds2250 (Post 4361850)
Do you know what the wastegate duty cycle is in the base map? I bet the ECU is "forgetting" the cobb realtime map.

Say what ?

suds2250 03-30-2013 07:14 AM

It's happened to me a few times. I was having battery issues, so I had to reflash the realtime map.

cryo 03-30-2013 07:55 AM

Like invar said, iam/dam is dropping to reduce boost and timing because the ecu is seeing significant knock. Its a safety feature the ecu uses to try and reduce power.

You either need a tune or there is something mechanically wrong.

Hope that helps.

Dave

bg. 04-13-2013 08:21 AM

Compression test shows engine is sealing great, all cylinders are within 5%, upon visual inspection everything is okay and sensors seem to be fine. We were lead to believe that this was happening due to false knock from the built motor, and forged pistons.

The car is dropped off with my tuner and is being protuned at the moment, this should correct the issue, fingers are crossed.

Thank you very much for all your input guys, I wish I had gotten my car tuned sooner.

KCwagon 04-13-2013 03:53 PM

You'll be happy you did. GL and let us know how it runs after the tune.


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