I recently had to replace the motor in my 2004 5.4. It ran good for about a week after I got it back and then I got a knock sensor code and it is running just like it did before it blew. I don't know how much the sensors control so I was wondering if this sensor could have been my problem all along causing the failure of my last motor? I never got a code before my last motor blew but I know that doesn't mean there couldn't have been a problem

 

Post the DTC.

 

P0325

 

A start?

https://www.f150online.com/forums/20...0325-code.html

AFAIK - a faulty KS1 or KS2 will not directly grenade an engine - if anything you'll simply lose power as the PCM thinks detonation is occurring and agressively pulls timing.

But - if NO signal is being generated AND an actual condition IS causing severe detonation, then over time it could be cause for concern, because the PCM ISN'T reacting as it should to negate it. But this assumes there is another pre-existing condition that is causing the detonation - it's not the KS's fault in and of itself - you just lost the instrumentation.

Good luck - Jbrew's on the case

MGD

 

Ok that helps. I'm hoping this is an unrelated issue and all will be well after the sensor is replaced. I had the problem for months and the truck spent a lot of time at the dealer without them being able to figure out the problem before it finally blew. Being that I have a new motor is there something that wasn't replaced that could cause this besides just a faulty sensor? Thanks for the help guys, I just don't want to end up in the same situation that I was 3 months ago after spending thousands on the repairs

 

Snake a magnet around the sensor, - make sure their isn't any tools pinned against , like a socket, extension, half a bologna sandwich, -you get the idea.

On the three valve, - they don't sit in the bottom of the valley. More like up on the shelf lol. I'll see if I can find a pic, - you might have two ??? Hang on.

 

 

Well, I haven't seen two knocks on the truck engines. - No that will not cause your motor to blow. If clear from foreign matter, you either have a bad sensor, short in the harness or a PCM problem. That's the 123. If you want further diagnostics info, specify procedure or spec info desired.

 

The dealer is supposed to be letting me know if the sensor is covered under the warranty from the motor replacement. Hopefully it will be and that will mean they have to fix it if its a short or faulty sensor. Im really hoping this is the issue, if not it may be that it was my pcm all along which is going to mean another pricey repair.

 

The dealer called back and want $375 to replace the sensor. Is there any way to tell that it is infact the sensor before spending that much? My dad has an 07 5.4 4x4, the same as my 04. Is it worth a try putting his pcm in my truck to see if this resolves the issue?

 

if the dealer wants to do diagnosis via parts replacement get your truck out of there, The dealer service departments should be able to tell absolutely if thats the problem.

 

Thats what their computer says it is but there may be no way of knowing if its a problem with the pcm

 

I would check the wiring harness for the knock sensor inspect it unplug the connector from the pcm and check it for continuity if it is open the computer will cause the engine to run like garbage. Im sure someone on here knows the pcm pin diagram and can tell you which pins to probe. If need be I can look it up for you tomorrow on alldata.

 

Thanks, Im going to talk to a friend of mine who is a ford mechanic about looking at it this week. Im in school so it will be this weekend before i can look at personally.

 

here's some ecm pinouts for the 04 f150
-Zach
F.I.S.T. Racing




knock sensor signal located here