2015 FoST Question

Looking at a 2015 Focus ST that has a little under 70k. Seller says it's not making boost and claims it's a bad turbo.  Seems low miles to lose a turbo. He says all the piping is fine. Other than a bad turbo, what else would you look for? No CELs and runs fine except for the boost issue, supposedly. Most on line sites seem to look to hoses, piping and the intercooler. 

Wastegate and BOV/CBV would be some other possibilities.

I'd be extremely surprised if there is both a lack of boost and a lack of a CEL unless the seller cleared the code and said "well, hey, there's no code *at the moment of me saying there is no code*"

In reply to cyow5 :

Exactly what I was thinking. Are these engines capable of running "smoothly" while internally on their way out? In other words, working great until they die 

In reply to Docwemple :

It can definitely run smoothly with a boost leak. The MAF will just read atmospheric. There's an extremely small (but not zero) chance that the ECU will not notice that there's no boost when some should be expected though

In reply to cyow5 :

Is turbo failure low on likelihood or is anything possible, considering the relatively low miles 

On my Fiesta ST, the lower intercooler hose would pop off under boost, you had to tighten the hose clamp from time to time. Everything else worked fine, it just ran like it was a base Fiesta without a turbo. A loose clamp can allow boost to escape without the hose coming fully off too. I would be very suspicious of hoses, especially with those miles. 

Good chance it's got a boost leak.  Just because he says the piping is good doesn't mean it is.

Thanks guys. This car is in Ohio. A bit of a haul from me. Anyone willing to lay eyes on it?

I have an '08 BMW 135i.  As was described, it also will occasionally pop the connection between the charge pipe and the intercooler causing no boost.  When it does though it definetely throws a CEL.  No boost and no CEL doesn't make sense to me.  If the owner is clearing the CEL without fixing the problem, I'd be suspicious of what else he's hiding.

If I were considering this car, I'd at least pull the intake tube off the cold side of the turbo and inspect.  Are all the impeller blades there?  How much play is there in the center bearing?  Impeller blades contacting turbo housing?  If the latter is true, I'd walk.  That contact will machine both the impeller blades and the housing causing all those metal fragments to be ingested by the engine.  

In reply to GopherBrokeRacing :

I asked specifically about what codes it's throwing, and he said 2 but hasn't told be which. So obviously a misunderstanding or something. I completely agree that I'd want to check the blades and bearing. It's something I do with my 7.3 powerstroke all the time, out of habit.

cyow5 said:

In reply to Docwemple :

It can definitely run smoothly with a boost leak. The MAF will just read atmospheric. There's an extremely small (but not zero) chance that the ECU will not notice that there's no boost when some should be expected though

If it were MAF with a boost leak, it would run horribly and immediately light the CEL.  You can't have a leak past a MAF sensor and the system not notice it.

BUT, the FoST is speed density.  So it will still run w/o boost.  It will still light a CEL because a leak upstream of the throttle is still bad- since it vents a lot of stuff to atmosphere.  And IIRC, there's a boost detection check, too- especially since there's a pressure sensor upstream of the throttle.  

Docwemple said:

In reply to GopherBrokeRacing :

I asked specifically about what codes it's throwing, and he said 2 but hasn't told be which. So obviously a misunderstanding or something. I completely agree that I'd want to check the blades and bearing. It's something I do with my 7.3 powerstroke all the time, out of habit.

So if there's no boost at all, it's either a plumbing problem (as discussed) or the turbo is 100% toast.  Which would manifest itself in a few ways that would be easily noticeable.  I've had a test car that ate some metal and chewed up the impeller.  Other than it sounding bad, it still performed quite well- I didn't notice there was a real problem until we had to do some updates.  Probably did a couple of dozen emissions tests with a torn up impeller.

I have seen a lot of Ecoboost underboost faults (and yes it sets a code) caused by a failed wastegate solenoid.

Waiting to hear back on what codes ate showing up