Anybody have this issue with their eco? Upon starting up there is like a compressor/hissing/vacum noise on. I think it goes away with giving it gas, but come back to idle it comes back. And the AC is not on. Its pretty profoun noise. Goes to dealer on friday, just wondering any thoughts.

I was thinking maybe a bearing is bad in something like the alternator or something or the turbos have something wrong with them, I dont know. This has happened in the last few thousand miles.

 

You're not talking about the turbos are you? Mine does it every time i start it up. Kind of like a "spooling" sound. Unless you are talking about something completely different.

 

no different it stays on

 

Not sure.. On mine when i start it i hear a hissing sound for about 10 seconds then hear a pop and it quits.. I always have a little bit of black smoke also every morning when i start it while its hissing but when it pops then the smoke stops. Only does the hiss and smoke on the first start up in the mornings

 

It may be the "vacuum activated brake booster". I am not fully sure what this component does, but it is a small box mounted near the drivers side radiator support. Only happens on the Eco, all the dealers are sold out, may be a future recall??

 

I'm fairly certain (based on hearsay and a little knowledge) that the ecoboost has a vacuum pump to provide the vacuum the brake booster requires.

It won't always run, but in cases like idling or startup it needs to run the vacuum pump to get the proper vacuum level for the booster.

At higher RPMs the engine probably generates enough vacuum so the pump shuts off.

It will probably also shut off the vacuum pump once the booster reaches the proper vacuum level.

It won't be long till we no longer have vacuum boosters. The brake suppliers are all developing electronic boosters to replace the vacuum boosters.

 

The complaint with this F150 Eco occurs right after startup and goes away within 5 or 10 seconds. I believe it is the vacuum pump for the brake booster. Dealer is out of stock, item is backordered so I suspect this may be a common issue. There are no drivability concerns, just this rather noisy pump for several seconds.