To much boost?

BMC10SEC50 · September 16, 2014, 01:33:00 AM

On it's own, the boost in my car went uncharacteristically high today. This caused serious sputtering due to the throttle and waste gate closing trying to control the pressure. Has anyone ever had this happen to their car?

I'm gonna have to put my car back to stock and hope it can be figured out.

FoMoCoSHO · September 16, 2014, 01:46:09 AM

What is "uncharacteristically high?

BMC10SEC50 · September 16, 2014, 01:48:55 AM

22

Spoolin-SVT · September 16, 2014, 02:05:49 AM

Yeah that does seem a bit high, what kind of boost are you usually seeing? Maybe because you have off road down pipes with a good free flowing exhaust that many don't have? If your running an off the shelf tune that is.

SHOdded · September 16, 2014, 06:34:06 AM

I've seen it that high (safely) in only 2 instances on the EB: either it is an F-150 or it is a transverse EB with 4DR's mods. Were you WOT at the time or ...? As mentioned, does your tune accommodate the offroad pipes? Could be turbo piping also, in addition to a wastegate beginning to stick. A quick look at possibilities:

http://diagnosecarproblems.blogspot.com/2010/04/what-causes-boost-spikes.html

BMC10SEC50 · September 16, 2014, 03:42:52 PM

The tune has it at 15lbs and for some reason it's jumping up on its own and when it does this the car sputters or misses so its not running right. I put the stock tune back in and it's still doing it.

Any Ford mechanics out there???

IHeartGroceries · September 16, 2014, 03:54:13 PM

More details...

Is it spiking briefly when you go WOT, or is it over boosting, like holding at 20+ psi?

Take it easy on the throttle. Over boosting will grenade an engine pretty quickly.

The is a control circuit which, I believe on the EB, bleeds boost away from the WGA to control boost, and meet targets. If there is an issue with that circuit, the WG flapper will not open and therefor there is a loss in boost control. Possibly as simple as a hose which has come loose, or an electronic solenoid which has failed.

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BMC10SEC50 · September 16, 2014, 04:21:09 PM

Pretty sure it's spiking and not holding it. You can hear the turbos spitting when your at WOT.

IHeartGroceries · September 16, 2014, 05:12:54 PM

I Anybody know if the EB uses a bleed type control circuit?

With a bleed type circuit, there's a pressure source from downstream the turbo compressor, which lands on the wastegate actuator, which then actuates the wastegate linkage, opening the internal flapper in the turbine housing.
There's a electronic solenoid valve which is T'd into the pressure tubing. The ECU sends a duty cycle voltage to the solenoid which then actuates a valve, bleeding pressure away from the waste gate actuator, and back into the intake tract, upstream of the turbocharger.

If any part of this circuit is malfunctioning, there may be a spiking or over boosting condition. I'd imagine the gate flappers themselves aren't sticking, as the turbos are internally gated.
There's various, small tubes plumbing all of this s*** together which can rot, or pop off. The actuator itself can malfunction. The solenoid valve may be sticking. The coil on the solenoid bad. The electrical circuit could be malfunctioning...

The bleed type circuit sucks, becasue there's no failsafe, other than the ECU cutting fuel or closing the throttle or whatever. It is mechanically inferior to other methods.

Even still...I'm not sure what the EB uses. I'd presume bleed type, like most other OEM.

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BiGMaC · September 16, 2014, 05:25:03 PM

bill...How is the boost being monitored? ... What LME tune are you running?... And do you have a 3BAR MAP

Definitely sounds like something is wrong.

I am a bit confused as these numbers are well above the numbers I had believed the stock turbos could generate even in a spike. And without a 3BAR the MAP sensor can't communicate boost levels much past 14psi to the ECM.

BMC10SEC50 · September 16, 2014, 05:33:57 PM

Bigmac- I sent you a PM.

IHeartGroceries · September 16, 2014, 06:56:08 PM

There has got to be other methods for the ECU to poll sensors for data, given the limitations of a 2 bar MAPS. There's no way that an over boosting condition would just go undetected, without some type of failsafe kicking in. With a 15 psi limitation of the MAPS, that'd mean any over boosting due to failed componentry could lead to catastrophic failure, without another means of monitoring boost pressure.

I can't believe Ford would even place a 2 bar in a system which generates as much boost as the EB, even from the factory. Are we sure OE isn't a 2.5 bar?

Even a small turbo without any type of control can boost to the sky, enough to daylight a rod. There really aren't limitation, outside of efficiency.

And OP, if you're experiencing a type of fuel cut or other failsafe, that's your ECU saving your engine. So, take it easy.

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ecoboostsho · September 16, 2014, 07:21:29 PM

There is a 3 bar map before the throttle body from the factory I believe. It can spike when the throttle snaps shut. Which one are you monitoring?

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ZSHO · September 16, 2014, 07:29:27 PM

Any DTC's on the my cal? Also when you put it back to stock,did you perform the adaptive relearn,so your car relearns its idle and fuel trim strategy for optimum driveability and performance or check the knock sensor wires?

BiGMaC · September 16, 2014, 08:15:02 PM

Quote from: ecoboostsho on September 16, 2014, 07:21:29 PM
There is a 3 bar map before the throttle body from the factory I believe. It can spike when the throttle snaps shut. Which one are you monitoring?

That's the TIP.... (Throttle-body intake pressure)... Is there even an access formula for that. BOVs should relieve all the pressure when the throttle is released shouldn't they?