Seems_LGT Posted August 14, 2014 Share Posted August 14, 2014 Hello everyone lately Ive been dealing with a weird boost issue that will pop up intermittently Normally the car will hit full boost 15-16 psi then every now and then after shutting the car off and starting it back up it will only hit about 7 psi which ive been told is about wastegate pressure? After this happens the car will continue to only reach 7 psi even after shutting off/starting car and will only go back to full boost after an ecu reset. I am currently running a cobb ots 91ACN tune Any ideas? Link to comment Share on other sites More sharing options...
JmP6889928 Posted August 15, 2014 Share Posted August 15, 2014 Perhaps a bad wastegate actuator. Sometimes they have that kind of annoying problem that is not consistent. Also check the vacuum hoses on the turbo too. There has been several people that have found tears in the hoses and that could definitely be a problem of inconsistency. The other thing it could possibly be is that your wastegate bushing has begun "the slide" and it's not lining up the wastegate flapper perfectly anymore and is moving up and down enough to allow pressure to pass one time and then seal just good enough the next. Look at the bushing and see if it's either sticking up further (look for a line on the bushing) or pushed down further into the exhaust housing. Good luck Link to comment Share on other sites More sharing options...
Seems_LGT Posted August 15, 2014 Author Share Posted August 15, 2014 The part that im confused about is that after a ecu reset everything goes back to normal Link to comment Share on other sites More sharing options...
chato Posted August 15, 2014 Share Posted August 15, 2014 could be going into limp mode. have you checked your IAM (DAM on AP) when you can't hit full boost? Link to comment Share on other sites More sharing options...
Seems_LGT Posted August 15, 2014 Author Share Posted August 15, 2014 I have not I'll datalog when it is hitting full boost and when its not to compare What should the numbers normally be? Edit: Nvm I looked it up, am I correct in believing that the number should be 16? Link to comment Share on other sites More sharing options...
chato Posted August 15, 2014 Share Posted August 15, 2014 should be between 0 and 1. if it's less than 1 the engine is experiencing some pretty serious knock, most likely a vacuum or boost leak. Link to comment Share on other sites More sharing options...
Seems_LGT Posted August 16, 2014 Author Share Posted August 16, 2014 Managed to do some datalogging today will upload once I figure it out but the DAM stays constant at .6 After some reading I believe this may be due to the cobb stage2acn91 ots tune which starts at a lower DAM value and learns up to 1? If anyone can give clarification on this that would be awesome As far as feedback knock/fine knock learning goes feedback stays constant at 0 and fine knock learning will occasionally see values of -.35, -.53, -.1.4 Link to comment Share on other sites More sharing options...
chato Posted August 18, 2014 Share Posted August 18, 2014 I believe it starts at .875 and should work up to 1 pretty quickly after a reset. if you're at .6 for any period of time, you have some significant knock events happening and I'd start investigating leaks. Link to comment Share on other sites More sharing options...
05subileggygt Posted August 19, 2014 Share Posted August 19, 2014 Possibly a bad factory boost control solenoid. Or the ecu knows something is wrong with the car and is putting it into limp mode as others said. Link to comment Share on other sites More sharing options...
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