mikane24

hi evom,

i was cruising yesterday and my rpm was at 3k, i press the gas half way and i see 15psi on my boost gauge, all of the sudden i felt that the car bucks a little and the service engine soon lite on.

when i got home i check the code with my obd reader, and the code is po172.
i went online to check what it is, it says that my fuel is too rich?

so last night i did some pulls and i am seeing 11.4 as my afr it used to be 10.9 after the tune to be safe and my boost increased from 27psi to 29psi so i am 2 lbs above without touching my boost control.

can some of u guys tell me what this is? i am really aware of this matter.

mikane24

anybody?

erald01

iTrader: (5)

boost spike, check your vacuum hoses that go to ur wastegate and the ones to the boost controller and make sure there is no pin holes. Has there been any weather changes?? boost sometime varies when the ambient temp changes, plus its not abnormal for the tune sometimes to flactuate on its own, so just keep an eye on it, worst thing is that you might have to retouch the tune a bit. Btw your afr seems good still 11.4 is not bad, but you def dont want to get any leaner at WOT.

mikane24

yes it was kinda cold last night but how would it be a spike bro if i am seeing solid 29psi to the red line? but my tuner said i might have boost leak?

erald01

iTrader: (5)

exactly cold weather/cold air is more dense and your boost will increase a little. Boost leak usually means less boost not more boost (boost spike). As i mentioned check the hose that goes from your wastegate to your boost controller, then go from there.

mikane24

it was kinda weird my tuner said its boost leak wtf im sorry i'm really a newbie on turbo

mikane24

anybody got any answers?

evox23

iTrader: (1)

Any updates?

jojobanks

what kind of boost control do you have?

I could see a mechanical controller fluctuating with the weather like that, but if it's a 3-port then it should be regulated by the ecu and should auto-correct.

If it's mechanical go ahead and check for boost/vaccum leaks for good measure, but you'll probably just end up dialing the boost back a bit till it warms back up.

If it's electronic then this is a wierd problem. A leak near the boost solenoid could be causing your controller to over-correct thus adding 2 extra psi.

Either way, doing a boost leak test and checking your vaccum with a mechanical guage will tell you alot (electronic guages often don't react fast enough to changes). Regardless of any problems I generally do both at least once a month just to be sure.