Engine shuts off while driving in cold weather

ALAN.CHILA

MEMBER
1996 FORD RANGER
2.3L
4 CYL
2WD
MANUAL
152,000 MILES

Only when it is less than 40 degrees outside the engine will cut off while driving. Today it is 30 degrees and it drove about five miles across town before it started cutting off, after that it would cut off every couple of miles. I was in third gear driving between 35 and 40. I let the engine warm up before driving. When it is over 40 degrees it never happens.

7 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

When this happens, does it restart right away? Have you noticed any odd smells or smoke from the exhaust?

Let me know. Also, let me know if the check engine light is staying on when the engine is running and if you have a live data scan tool.

If you do have a live data scanner, check to see what the signal from the ECT (coolant temperature sensor) to see if it is close to ambient temperature. Also, when driving the vehicle, leave the scanner connected and watch to see what the temperature indicates when it stalls.

Let me know,

Joe

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Sunday, January 2nd, 2022 AT 7:16 PM

ALAN.CHILA

MEMBER
4 POSTS

Joe,

Thanks for your help in trouble shooting this cold running cut off.

No smell or smoke from exhaust. Check Engine light only comes on when it shuts off and starts right away and it goes out. No CEL when I turn the key off to restart

It is 28 degrees out tonight. I plugged in my Cen-Tech Scan tool and went for a drive, the ETC at startup was 60 degrees, the same temperature as in the garage. The ETC was around 165 degrees once it warmed. After about five miles I could tell it wanted to cut out, so I pushed in the clutch and it cut off, the ETC was at 163 degrees and it started up right away as always.

I checked for stored or pending code it came back with none.

Thanks,

Alan

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Sunday, January 2nd, 2022 AT 8:11 PM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Okay, that sounds like it's working properly. When it stalls or feels like it's going to stall, does the tachometer jump at all?

One more thing. With the engine running, what are the short-term fuel trims? I'm questioning if it is a fuel pressure-related issue.

Joe

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Sunday, January 2nd, 2022 AT 8:36 PM

ALAN.CHILA

MEMBER
4 POSTS

Joe,

When I feel it is going to cut out while driving the tachometer will drop/stumble 100 RPMs with the engine. It does not jump around.

The SHRTFT1 (%) was usually around 7.0 but would go up to 10.0 and down to 3.9 mostly staying between 7.0 and 10.0. I attached a 30 second video of the numbers changing.

Thanks,

Alan

Video (Click to make bigger)

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Monday, January 3rd, 2022 AT 6:34 AM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

If the trims are going up that high, chances are there is either a vacuum leak or low fuel pressure. I was unable to see the trims in the video. However, in a perfect world, the trims would be 0. When it goes into the + numbers, the computer is adding fuel to the engine. When it drops below 0 into the negative numbers, that indicates it's trying to lean the fuel mixture.

Normally, trims are between -10% and +10%. but they should be adjusting back and forth and not just in the + side.

Have you checked fuel pressure? Have you checked to see if there are any vacuum leaks? Here are two links that explain how to look for both:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the manufacturer's specifications below for pressure.

Let me know what you find. Also, watch fuel trims when you feel the problem starting.

Take care,

Joe

See pic below.

Image (Click to make bigger)