Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

2005 ford E250 VACUUM LEAK

Hi. y’all
my my truck has a vacuum leak or something. it will not start no mater what i do until i take off the vacuum house that goes from the back of the throttle to the right side of the valve cover. and when it running if i put it back it stop.
i have changed that vacuum hose and the connector on the valve cover.
any idea what is going on here?
j ma.

If you’re removing a hose from the throttle body, that’s allowing air into the engine.

Have you tried slightly stepping on the gas pedal while starting the engine?

If the engine starts when doing this, the problem is with the Idle Air Control valve.


Yes it will not start. The engine just turn over and only fire on the left side of the engine. I can tell it the only side that fire because it the only one that the smoke is coming out.
But when I disconnect the hose the truck start fine. Till I step on the throttle then it dies.

What does the hose tie to on the other end of it? Also see if removing other hoses going the throttle body does the same thing.

When I take off the left side hose and connect the right side does not start

Are you disconnecting any wiring? Is it the rubber throttle body intake hose that runs from the air filter to the throttle body?

Yes but non of those are disconnected. I am puzzled my mechanic didn’t know what is wrong with it.
It has An electronic throttle.
Very black smoke when it runs if this helps

From the things you say about the trouble the engine is looking to get some air in order to start up. I would assume the air filter is okay. You need to check the intake airway, air sensor, and other things related to the air system for a problem.

On the other hand, I suppose there could be a problem with the fuel system and maybe there is fuel leaking into the engine while it is not running. Like a leaky injector or the MAF or O2 sensors are making the fuel rich condition.

Remove the intake hose from the throttle body. While watching the throttle plate, have someone turn the ignition on. The throttle plate should slightly open.

If the throttle plate doesn’t open, there’s a problem with the throttle body.


Mouse nest in the air filter?

Very black smoke when it runs is a clear sign of an over-rich engine. Either fuel injectors are leaking or fuel pressure is way too high. And, you should have a lit CEL and DTCs stored.