Ford: 96 Mercury Grand Marquis No-Start, mercury grand marquis, crank pulley

Question
QUESTION: Hello,
I have a 96 Mercury Grand Marquis with the 4.6L engine.  I've had it for several years with little to no trouble.  I drove it yesterday and everything was fine, I parked it at 9PM last night.  This morning I went out to the vehicle to go to work and it would turn over but would not start.  I checked the inertia switch, fuses inside the vehicle and fuses inside the fuse block in the engine compartment and all appeared fine.  I can hear the fuel pump come on Key-on engine-off and it builds pressure (1-2 seconds) and shuts off just like normal.  I popped the cap off of the schrader valve on the fuel rail and verified fuel pressure is making it to the rail (squirted out with force, hit the hood), so I'm out of ideas.  All wires appear to be in place and I'm not sure where to start.  Like I said, I've never had a problem, so I'm not sure if a coil pack could fail that fast, or if it's the PCM or something else.  Any help is greatly appreciated as this is the only vehicle that we have and I'm relying on others for transportation to work.  I can't miss a day as I'm a manager of a wrecking yard here and open and close for my crew.  I have access to most parts in my position, so I'm able to test/replace anything that is fairly easy to get to and get off the vehicle.

Thanks!
-James

ANSWER: Hi,


I am not near my resources right now, but I would suspect the crank sensor.

I can give you more on Monday, but if all the fuses are ok, and no signs of critters snacking under the hood, the cam and crank sensors would be next safest bet.

---------- FOLLOW-UP ----------

QUESTION: Thanks Tim.  I read something on the internet that stated that if the CEL doesn't go off when cranking that it's definitely a crankshaft positioning sensor.  If that is true, it's the crank sensor.

I'd like to tackle the replacement on my own... does it require the removal of the crank pulley or any special tools for installation?

I didn't think to mention before, but for the last few months I have noticed a "lag" or delay in acceleration, like the car lulls for a second then gets into power.  From what I've read, that's another symptom of a failing crank sensor.

I'd appreciate anything that you've got for me.  Thanks for answering my question so soon.

-James

Answer
hI AGAIN.

tHE CRANK SENSOR IS ON THE FRONT PASSENGER SIDE OF THE MOTOR, JUST BEHIND THE a/c COMPRESSOR.

You will have to unbolt (not remove) the compressor to replace the sensor.

While this can cause stumble, I would have a god look at the fine wire in the MAF  (mass air flow sensor) in the air tube between the air cleaner and throttle body.  If you see any dirt on it, spray with carb cleaner and use and old toothbrush gently if it is very dirty.