Mom's Car: Intermittent No Start

[Oil Changer]

'98 Grand Marquis. 145k miles. Daily driven by old lady. 50/50 mix city/highway slow old lady speed driving.

Crank/no start. Will start with judicious spray of starting fluid (I know). Once running it runs fine. Will re-start once it has been started with the aid.

Can go for days without issue. No codes. Extremely well maintained. Open to any suggestions.

 

[cmorr]

Have you checked the fuel pressure at the rail after it has sat for awhile. Am betting fuel pump (pressure bleeding down after it sits)

 

[mechtech2]

You have narrowed it down to fuel. Good.
Try turning the key to ON for 3-4 seconds before cranking it. let us know.

 

[beast3300]

Try cleaning the IAC motor.

 

[92saturnsl2]

Originally Posted By: mechtech2
You have narrowed it down to fuel. Good.
Try turning the key to ON for 3-4 seconds before cranking it. let us know.


I agree with this, but I will add that it might be helpful to repeat this a couple times before starting, as it can take more than one "priming" if the pressure has bled down all the way.

To repeat the fuel pump priming, some vehicles require you not only to toggle the key between Lock and On, but also to open the door after taking the key out, which kills all power to the ECU and accessories. <-- this is the feature that keeps the radio and other power on until you exit the vehicle.

 

[jegs]

Change the fuel filter. If that doesn't help it's probably a bad check valve in the fuel pump or a leaky injector(s) causing the system to loose pressure after sitting.

 

[Oil Changer]

No, but a mechanic friend suggested fuel pump when I described the problem to him.

Originally Posted By: cmorr
Have you checked the fuel pressure at the rail after it has sat for awhile. Am betting fuel pump (pressure bleeding down after it sits)

 

[Oil Changer]

I tried that; even "bumped" the engine. Could not hear the buzz of a pump, nor did it start after (until I sprayed it).

Originally Posted By: mechtech2
You have narrowed it down to fuel. Good.
Try turning the key to ON for 3-4 seconds before cranking it. let us know.

 

[Oil Changer]

Okay. I will.

Originally Posted By: beast3300
Try cleaning the IAC motor.

 

[Oil Changer]

Filter was changed in the fall with a Motorcraft filter.

Originally Posted By: jegs
Change the fuel filter. If that doesn't help it's probably a bad check valve in the fuel pump or a leaky injector(s) causing the system to loose pressure after sitting.

 

[OVERKILL]

If you can't hear the fuel pump, you may also want to check the fuel pump relay.

 

[mechtech2]

Then if you tried it, the pump is faulty or not getting power. A bad relay, some stupid oil pressure safety, or connection are things to check.
If you heard no noise, then the filter is not the problem, BTW.

 

[Oil Changer]

Dug this up to report the fix.

Grand prize goes to beast3300. It was the IAC motor. Easy/cheap fix. Car runs like new again.

I was told this is common.