Hey guys just got my 2016 fiesta st not too long ago and the car is now throwing a underboost code (p0299) and is running absolutely awfully so immediately I checked my charge pipes and there wasn’t any popped. And then I decided to start checking vacuum lines and couldn’t find anything there either. Cleaned my throttle body and MAF and nothing as well. The car does have an aftermarket turbo and downpipe and exhaust. My next guesses would be boost control solenoid or a boost control sensor. And no the car is not blowing any kind of smoke and there isn’t any oil in the intake system or any oil coming out of the exhaust. Could use a little help here considering I’m new to the community. I also attempted to check the wastegate to see if the rod coming out of it could and would open and it would but that still doesn’t mean it couldn’t be messed up right ? Just want my car running good again it was so much fun while it ran right . Any suggestions or help will mean the absolute world. Thanks
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Undeboosted.
- Thread starter tyler2687
- Start date
Thread Starter
#6
and thank you @FiestaSTdude for welcoming me to the forum! And thank all you guys for the help! I’m gonna rip back into the car today so I’ll let you guys know how it goes
Thread Starter
#8
Checked the car out all last night and pulled down every charge pipe and checked the intercooler for cracks and nothing. Then really checked over the charge pipes well. Got new and a little bit wider hose clamps and tightened them all down really well cleared the codes and took the car for a ride and still nothing. Still feels like the car is just running on all motor in all honesty
https://www.autocodes.com/p0299_ford.html
Check out this link and start looking into the different things they say to fix it. Maybe start with the cheapest/easiest fix. None of what they said jumped out as something I've heard of before.
Do you have any other codes?
Check out this link and start looking into the different things they say to fix it. Maybe start with the cheapest/easiest fix. None of what they said jumped out as something I've heard of before.
Do you have any other codes?
Boost control solenoid for sure should be checked. Do you have a boost leak tester and an air compressor? The only way I’ve been able to locate boost leaks is to charge the whole system up to 15-20 psi and spray soapy water on every connection. Could be the BPV as well.
A leak before the turbo can’t cause boost problems. Exhaust leak preventing all of the exhaust from being routed to the turbo could. A boost leak could. Could also be a blown turbo or a wastegate actuator that’s gone kaput and is opening at like 2 psi or something incredibly low. That’s way less likely than a boost leak, however.
A leak before the turbo can’t cause boost problems. Exhaust leak preventing all of the exhaust from being routed to the turbo could. A boost leak could. Could also be a blown turbo or a wastegate actuator that’s gone kaput and is opening at like 2 psi or something incredibly low. That’s way less likely than a boost leak, however.
