Did I really just fix extended crank that easily? - 2007 Mercury Montego

Joined
Jan 16, 2009
Messages
59
Location
Midwest
2007 Mercury Montego

Bought it used a few years ago with 140xxx miles. Now around 172xxx. Ever since we bought it, it has struggled with an occasional extended crank before starting. Back during the early days of covid lockdowns, I changed the fuel filter and thought that helped it a good bit. But recently I drove the car (usually my wife drives it) and realized that it had gotten pretty bad again. So I changed the filter a second time with no success.

Unfortunately this particular vehicle has no schrader valve on the fuel rail to check the pressure. And no easy way (for me) to tap into it. I did monitor the fuel pressure PID in Forscan and, according to the pressure sensor in the rail, it did not seem to be a fuel delivery problem.

On a whim, I pulled the MAF sensor and lightly tapped it on the airbox. Some fine dust particles fell out. I had a new can of MAF cleaner on hand so I gave the sensor a liberal cleaning. Reinstalled sensor and it has been starting just fine since then. (2 days so far) I can't believe it was that simple. I'm suprised the sensor was dirty enough to cause problems starting but yet there were no other driveabilty issues.
 
Joined
Apr 9, 2008
Messages
15,969
Location
Central NY
On my Cherokee the extended crank is fixed by replacing yet another fuel pressure regulator in the tank. That works for about a week.

Then it's another $30-$300 regular that will last a week.
 
Joined
Jan 13, 2016
Messages
3,489
Location
Northeast Nebraska
I'd check the air filter to make sure there are no tears and make sure the filter is sealing good.

Or, it could just be 172k worth of build up if this is the first time cleaning it.

I had a 99 LeSabre that had a touchy MAF sensor, always started right up but would develop a slight pause on take off, kind of nerve racking pulling out into traffic.
 
Joined
Jun 26, 2018
Messages
325
Location
AR
Don't forget the 8% environmental fee that is added to every invoice! Maybe I should generate an invoice and see if my wife pays it...
And hazardous waste disposal fee for the used contents of the aerosol can.
 
Joined
Mar 15, 2012
Messages
1,648
Location
PEARL River la
On my Cherokee the extended crank is fixed by replacing yet another fuel pressure regulator in the tank. That works for about a week.

Then it's another $30-$300 regular that will last a week.
Did you do bypass in fuse box? Been a while since I done these but if I remember correctly fuel pump has a paper with instructions that will make sure you get correct voltage to fuel pump. Sorry to hijack the thread.
 
Joined
Apr 9, 2008
Messages
15,969
Location
Central NY
Did you do bypass in fuse box? Been a while since I done these but if I remember correctly fuel pump has a paper with instructions that will make sure you get correct voltage to fuel pump. Sorry to hijack the thread.
There's a check valve in the pressure regulator that stops the pressure from bleeding off. That's the part that fails almost immediately.

I did add in a switch so I can press a button on the dash for 5 seconds to prime the fuel pump and start it without having to cycle the key 27 times. It jumps the fuel pump relay.
 
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