Hi all, I posted just a couple of days ago about my 05 Subaru Outback wagon stalling out on me immediately after starting and putting it in reverse. As a reminder about my previous post, I shared that when this happened 4 months ago the mechanic thought it might be a loose battery connection. He had done a complete diagnostic and couldn’t come up with a firm cause. In fact by the time he was able to look at my car it was no longer stalling out.
Today, thankfully (sort of) the car still would not stay running even after 3 days of sitting at the mechanics shop. The new mechanic said that the Mass Air Flow hose was disconnected and dirty. I’ve been researching Google nearly all afternoon and I haven’t been able to find a situation where this caused someone’s car to die out.
Oh and my check engine light has never tunred on.
Thanks for any help! And before anybody gets testy regarding the mechanic, I do realize that he is only able to give his best educated guess. Its not my intention to insult mechanics. I would simply like to have a reasonable diagnosis, I’m a Mom of 2 little boys who lives in the higher Rocky Mountains and I need to be able to depend on my car.
Yes, it can. My car was stopped by a lady bug stuck on the MAF sensor wire. (It got in because the filter box was not closed correctly.) The car in question was a 2006 Lincoln LS. I, too, was surprised that a failed MAF sensor completely prevented the engine from running.
Your question is poorly worded and again it is in the details. Is the mechanic saying the large connective bellows (loosley called a hose)down stream of the sensor was not connected to the throttle body? This will cause stalling but it would not be to hard to see.
Is the mechanic saying a smaller hose connected either up stream or downstream of the sensor was disconnected? Upstream would not matter downstream would allow unmetered air but not necessarily cause stalling.
Debris on the heated wire part of the sensor will set a code (P0101) (P0102)
I believe what you are getting at is you don’t think the mechanic has found the source of the stalling.
As oldschool said, I’m not sure what is the root of your problem.
On “Can the Mass Air Flow sensor cause a car to die?” Yes, is my answer as that’s what happened to me with a Volvo ('98 V70XC). The check engine light had come on twice and was reset by my Volvo independant shop to see if the problem recurred. It did with some erratic behavior, stalling and then running fine a couple of times. One day it just stalled and would not restart and needed a tow to the shop. New one and all fine after that.
Thank you for your reply, pointing out that my post is poorly worded lets me know that my mechanic isn’t good at communicating the problem. I will be sure to address it with him. I can only post as much detail as I’m given from him so this is very informative.
I think the mechanic was just using simpler terms to make the problem, of the direct cause, more easily understood by the lay person.
What the mechanic probably found was that the large black tube the MAF (Mass Air Flow) Sensor is in, was loosely connected at either end. There are some large clamps, usually, which hold the tube in place.
When the air filter was last replaced, the large black tube was disconnected to facilitate changing the air filter. When the tube was put back on, it wasn’t put on properly, resulting in an unmetered air bleed. The MAF Sensor measures (meters) the amount of air entering the engine for combustion. The amount of fuel sent into the engine is metered. The bleed air (air leak) messed up the fuel and air mix, and the engine stalled.
Some less scrupled mechanic may have seen this as an opportunity to sell you an expensive MAF (Mass Air Flow) Sensor.
I’m old enough to remember when getting a car set up for sea level operation to start and run at high altitudes was often an operation that required hours of carburetor adjustments and a lot of profanity. That was fixed in later decades and shouldn’t be an issue with modern computer controlled ignitions. But I wouldn’t be surprised if minor air/fuel mixture problems that wouldn’t matter down here where most of us live and don’t set an error code, might cause starting/driveability problems up where there is substantially less Oxygen to work with.
I think there is a good chance that your mechanic is right.