Knocking and stalling only when engine has warmed up

CHRESTIAN WALKER

MEMBER
2006 FORD F-150
5.4L
V8
4WD
AUTOMATIC
168,900 MILES

I having a issue with my truck it will run fine when it is cool and just starting and then the engine warms up and sometimes starts knocking really loud. Then the truck will stall at a complete stop. There is no check engine light on and no code coming up and I don't know why would the crankshaft sensor cause this? Also, I have another question. I had my A/C compressor replaced and the guy hooked it up and now it just keeps blowing fuses when I turn it on. Any idea what this could be? Please help!

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,779 POSTS

It sounds like a short. Check the wiring at the compressor to make sure nothing is pinched or damaged.

As far as the engine, the stalling when warm does sound like a crankshaft position sensor, but the knocking usually isn't associated with it.

Take a look through this link and let me know if you feel it mirrors what you experience:

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

Also, if you could record the knocking so I can hear it, it may be helpful.

Let me know.

Joe

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Monday, April 26th, 2021 AT 12:55 PM

BMDOUBLE

MECHANIC
1,139 POSTS

An oil pressure test would be a good idea, but these engines are known for the knocking sound coming from either the cam phasers or rod bearings, root cause sometimes being lack of maintenance like oil changes, but I've seen engines with less than two thousand miles make knocking noises. On this engine, never ever go more than five thousand miles between oil changes! https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

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Monday, April 26th, 2021 AT 12:55 PM

KEN L

MASTER CERTIFIED MECHANIC
47,756 POSTS

Can you please shoot a quick video with your phone so we can hear the noise? That would be great. You can upload it here with your response.

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Monday, April 26th, 2021 AT 12:55 PM

CHRESTIAN WALKER

MEMBER
4 POSTS

I got my A/C to work but still have issues with my truck. I ran the scanner on my truck and it says system pass no faults detected but when I look under pending codes I get P0340 and P0344 camshaft position sensor bank 1 cut a. One says malfunction and then the other says intermittent. Does that mean I should change the cam shaft position sensor on my truck and it should be okay or what? You all decide. Please let me know I really need to get my truck fixed so I can get back to work on Monday morning. Again there is no check engine light coming on on my truck at all, but that’s what my Actron scanner is saying under pending codes, but diagnostic code it says system pass no faults detected. Can the cam shaft position sensor cause my car to start knocking and stall?

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Monday, April 26th, 2021 AT 12:55 PM

JACOBANDNICKOLAS

MECHANIC
109,779 POSTS

Pending codes are set when intermittent faults happen and the PCM needs to see happen consecutively.

The codes you have are slightly different. The P0340 indicates the PCM is intermittently getting a signal from the cam sensor and the P0344 indicates no signal.

With that in mind, I would check the connections at the sensors to confirm they are clean, tight, not corroded, and not damaged.

As far as causing knocking, anything is possible, but when there is no signal, it should go into a default setting. However, anything that has a partial control over timing can cause issues.

Let me know.

Joe