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After engine has warmed up it loses power and stalls

Tiny
CLIFF94
  • MEMBER
  • 2004 FORD EXPEDITION
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 151,378 MILES
After the car heats up, it will stall no matter what the speed is. It just loses power. I already replaced the fuel pump and filter and crankshaft sensor and have cleaned the mass airflow sensor. I hooked up to a scanner and it had no codes showing. I then tested the fuel pump and forced it on. When I did that, the relay was humming loud and got hot, but when I looked into it people said that that is normal because I was forcing it open. I don’t really know where to go at this point.
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Thursday, June 30th, 2022 AT 5:49 AM

18 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

That doesn't sound correct. The relay shouldn't be humming. All you are doing is close the circuit when you actuate it. It's like turning the light switch on at home. You will hear a click but at that point, power is being sent to the component.

Does it do this when the engine is cold? Have you checked the relay itself? If you haven't, switch it with a different one having the same part number. If there isn't one, here is a link that explains how to test a relay. I think (based on your description) the relay is bad.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know what you find. Also, let me know if the vehicle starts right back up after stalling.

Take care,

Joe

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Thursday, June 30th, 2022 AT 8:53 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
I haven’t gotten to test the relay, but I did swap it with another one that was the same and it shut off again once it got to running temperature and when it does stall I have to wait about a minute or two before I can turn it back on and it will crank sometimes it will shut right back down after I crank it up and put it in drive then I have to wait a little longer then it will crank and let me drive again.
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Sunday, July 3rd, 2022 AT 4:57 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

Are you certain there are no diagnostic trouble codes? Also, your description sounds like a typical faulty crankshaft position sensor, but you indicated replacing it already.

Take a look through this link:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Also, let me know if you have scanned for codes.

Joe
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Sunday, July 3rd, 2022 AT 6:39 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
I have scanned it but there were no codes thrown. So, I am going to test my fuel pressure and see if that could be it.
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Tuesday, July 5th, 2022 AT 4:34 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

Sounds like a plan. Let me know what you find or if you have questions.

Take care,

Joe
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Tuesday, July 5th, 2022 AT 9:34 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
Hey, it was the relay, it had a hole melted in it.
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Saturday, August 13th, 2022 AT 3:32 AM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
Here is the relay:
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Saturday, August 13th, 2022 AT 3:33 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,883 POSTS
Ooops that looks like it is the problem, good find, we are here to help, please use 2CarPros anytime.
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+1
Saturday, August 13th, 2022 AT 12:32 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
Thanks for all the ideas and help.
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Sunday, August 14th, 2022 AT 5:35 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

I'm glad to know you found the issue and it has been resolved.

As Ken mentioned, please feel free to come back anytime in the future. You are always welcome here.

Take care,

Joe
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Sunday, August 14th, 2022 AT 7:54 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
So, what are some suggestions for a car smelling rich?
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Monday, August 15th, 2022 AT 4:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

A rich fuel mixture can be caused by a faulty oxygen sensor, high fuel pressure resulting from a fuel pressure regulator issue, a faulty cooling temperature sensor, and so on. Does it have a rich smell?

Let me know.

Joe
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Monday, August 15th, 2022 AT 7:48 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
Yes, it does, I smell it most when I turn the car off and open the door.
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Thursday, August 18th, 2022 AT 6:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

Okay, if you have a live data scan tool, you can simply let me know what the short-term fuel trims are. Also, when the engine is cold, with the scanner check if the temperature reading is close to ambient temperature.

If the scanner isn't an option, the first thing to do would be to check the fuel pressure to see if it is within the manufacturer's specs. A faulty fuel pressure regulator can cause high pressure.

Here is a link that explains how to check fuel pressure:

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

Let me know what you find. If you do have a live data scan tool, it will make things easier, so let me know.

Joe
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Thursday, August 18th, 2022 AT 7:17 PM
Tiny
CLIFF94
  • MEMBER
  • 10 POSTS
This is what I got when I had access to a scanner.
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Sunday, October 2nd, 2022 AT 11:00 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

The trims look okay. However, the engine temperature is a little on the cool side. Was this after it was fully warmed up?

Joe
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Sunday, October 2nd, 2022 AT 9:07 PM
Tiny
CLIFF94
  • MEMBER
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Yes I believe so.
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Monday, October 3rd, 2022 AT 6:49 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

If the engine is warmer than what is indicated by the coolant temperature sensor, it can cause a rich fuel mixture. What was the approximate temperature the day it was checked? Also, we need to confirm it was fully at operating temperature. If it was, then the sensor may be the issue.

Let me know.

Joe
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Monday, October 3rd, 2022 AT 8:12 PM

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