Pricey Automobile Speak:
My husband and I are each nurses, so we’re educated to diagnose issues. My husband isn’t solely an important nurse however a effective yard mechanic as nicely. However we’ve got an issue with our 2015 Ford Escape that has us stumped.
After I cease at a pink mild, my automotive shakes violently, and the RPM drops beneath a thousand. After I put it in impartial or park, the shaking stops.
We took it to our mechanic, who connected a pc that confirmed no codes, no fool lights and no warning mild on the sprint. They dominated out a foul motor mount and brake rotors being warped, they usually cleaned the idle air-control valve. They’re stumped, too.
Please assist with this downside. If anyone can, you’ll be able to. — Marsha (for Marsha and Robert)
I’d offer you my analysis, Marsha, however I must see your proof of insurance coverage protection first. Sorry, little hospital joke there.
It may very well be any variety of issues, Marsha. However I believe you’ve got a vacuum leak. The engine naturally creates vacuum each time a piston descends and sucks gas and air right into a cylinder. That “free” vacuum energy is then utilized by different programs within the automotive. For instance, it’s utilized by the air flow system to manage the flaps inside your ducts, and by the exhaust fuel recirculation system to open and shut the EGR valve.
In case you have a vacuum leak, which means undesirable air is leaking into the cylinders. As a result of the combination of gasoline and air within the cylinders needs to be excellent, a vacuum leak throws off that delicate steadiness by letting in an excessive amount of air, and that makes the engine run tough.
There are numerous methods to discover a vacuum leak. If it’s sufficiently big, you’ll be able to generally hear it hissing. If not, we generally spray flamable gas cleaner the place we predict air is perhaps leaking in. If there’s a vacuum leak close by, that gas cleaner will get sucked into the cylinders, and we’ll hear the engine rev up. Or we pinch off particular person vacuum hoses, separately, to see if closing one off makes the engine run easily.
There are different methods, too. But when your mechanic is nearly as good as you say he’s, he’ll know easy methods to seek for a vacuum leak. I will provide you with one trace on your mechanic: One often-overlooked supply of a vacuum leak is the facility brake booster.
The facility brake booster makes use of vacuum from the engine to multiply the power your foot places on the brake pedal. It’s the “energy” in energy brakes. But when there’s a gap within the booster’s diaphragm, that’ll create a vacuum leak, however solely once you’re stepping on the brake — like once you’re stopped at a light-weight. If the leak is a small one, once you put the automotive in park or impartial, you scale back the load on the engine sufficient to cease the shaking.
So ask your mechanic to set out on an expedition for a vacuum leak, Marsha. Hopefully he’ll discover it, and your Escape can escape the shakes.
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