1991 Ford Aerostar

Engine Performance problem
1991 Ford Aerostar 6 cyl All Wheel Drive Automatic 171000 miles

The Van has been running very well but will not start when in very cold weather - below 25 degrees
and this has been an issue for several years.

Second problem- twice in the last 3 months - the motor just shut off while driving on the road- then after sitting for about ten minutes it will stat again.

Has been diagnosed and no codes show.
Has a new fuel pump & filter and after this was installed then the problem of shutting off while driving has occured.
We have tried starting Fluid- more than once.
What next?
Gloria Ann
January 3, 2010.

THis is a tough one without a code. My first guess with the cold start problem would deal with a temp sensor. The purpose if the sensor is to tell the computer the ambient temp and coolant temp. From that info, the computer determines how rich or lean to make the fuel mixture. What I need you to try is this. Purchase a can of starting fluid. When the van doesn't start, see if it will start with the starting fluid. If it does, we have one of two problems. Either the temp sensor is going bad or there is a problem with fuel pressure.

Let me know what you find.


We have already tried Starting Fluid, many times - this year and in past years. I really think most people know to try starting fluid. We had the computer check done and no problem. We think it is an inherent problem with Ford Vans and had hoped you or other techs had this question in the past.


Gloria Ann
Jan 8, 2010.
Actually, the reason I asked about the starting fluid is to determine if you are getting spark. And believe it or not, most people don't think to try it.

Also, I just reread your original posting and saw that you mentioned it, so sorry. I will assume it doesn't start with starting fluid which leads me to a spark problem. Have you checked the crank sensor to make sure it isn't corroded, dirty, loose.

No the Van does not start with starting fluid in cold weather. It is a cold weather issue. The Van always starts in temps above 25 degrees.
My husband said he knows where the crank sensor is
and if it is dirty or loose then one would think why would it work when the outside temperature rises above 25 degrees?
Just so you know- we use dry gas in winter months
in all of our vehicles.
So the next question would be does cold weather affect the crank sensor?

Gloria Ann
Jan 10, 2010.
THe temp can affect many things. I need you to check to see if there is spark when the engine doesn't start. We need to determine that is the problem. If it doesn't start with starting fluid, chances are there is no spark.

Let me know.