2004 - 2008 F-150

2008 f150 5.4

Thread Tools
 
Search this Thread
 
  #1  
Old 03-09-2020, 03:39 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
2008 f150 5.4

Crank .no start. No Rpm when cranking. Engine light stays on while cranking. New cam sensors and crankshaft sensors. Wire from sensors back to pcm tested out good. Voltage test at pcm pin was 10v in one wire 3 volts on other crank wire. Pcm disconnected I'm getting a good. 55 volt from the crank senor . When I unplug the cam sensor's I get no voltage or ground . Please help
 
  #2  
Old 03-09-2020, 04:17 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 43,214
Received 763 Likes on 706 Posts
Have you checked for spark, fuel pressure, and for injectors pulsing?
 
  #3  
Old 03-09-2020, 04:32 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Yes I have 12 power to coils but no pulse no spark. Good fuel pressure my guess is the pcm is not receiving the signal from the crank to turn on pulse but it's good wired and new sensor. I was told the pcm has to send out a circuit to the crank.
 

Last edited by Kitfox; 03-09-2020 at 04:39 PM.
  #4  
Old 03-09-2020, 05:28 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 43,214
Received 763 Likes on 706 Posts
Have you checked the PCM power relay and fuse?
 
  #5  
Old 03-09-2020, 07:11 PM
Roadie's Avatar
Senior Member
Join Date: Jan 2002
Location: Wilmington,NC
Posts: 5,994
Received 220 Likes on 200 Posts
Spray a little starter fluid into the intake and see if it starts. If it does, fuel supply problem, if not spark problem.
 
  #6  
Old 03-10-2020, 12:51 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
No fuel problem
and pcm relay is perfect
 
  #7  
Old 03-10-2020, 01:09 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 43,214
Received 763 Likes on 706 Posts
What about the fuse?
 

Trending Topics

  #8  
Old 03-13-2020, 12:30 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Crank no start 2008 F150

new cam and crank sensors. Wiring fron sensor to pcm tests good. Constant12v to coils and in jectoes with key on. But no pulse spark on cranking. AC voltage from crank sensor while cranking is .42 to .48 I get no Rpms on the dash and check engine light stays on during cranking. I'm getting no codes. Pcm relay checks out good. Is this voltage enough to get the pcm to send out the spark signal. Also fuel press is good
 
  #9  
Old 03-13-2020, 12:38 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Does anyone know where I can get the Pcm sensor wiring diagram.
 
  #10  
Old 03-14-2020, 12:34 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 43,214
Received 763 Likes on 706 Posts
Why did you start a new thread?

https://www.f150online.com/forums/20...150-5-4-a.html

Have you checked the FUSES?????
 
  #11  
Old 03-14-2020, 03:20 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
I m new to the site and wasnt sure how to post.
all the fuses are good
 
  #12  
Old 03-14-2020, 03:22 PM
Kitfox's Avatar
Member
Thread Starter
Join Date: Mar 2020
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
I posted the first day and then couldn't figure out how to get back there
 
  #13  
Old 03-15-2020, 04:23 PM
Dennis_461's Avatar
Member
Join Date: Dec 2019
Location: Atco, NJ
Posts: 18
Likes: 0
Received 7 Likes on 6 Posts
Originally Posted by Kitfox
new cam and crank sensors. Wiring fron sensor to pcm tests good. Constant12v to coils and in jectoes with key on. But no pulse spark on cranking. AC voltage from crank sensor while cranking is .42 to .48 I get no Rpms on the dash and check engine light stays on during cranking. I'm getting no codes. Pcm relay checks out good. Is this voltage enough to get the pcm to send out the spark signal. Also fuel press is good
Checking + voltage is only half the job.
You also need to check ground AT each of the devices.
How are you confirming no pulse at the coil-on-plugs?

I would try squirting starting fluid in, maybe figure out if the fuel delivery is the problem.
 
  #14  
Old 03-15-2020, 09:31 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 43,214
Received 763 Likes on 706 Posts
You need an online spark tester to check for coils firing, noid lights to check for injectors pulsing. Most parts stores have them in their loaner tools.

Spark tester:



Noid lights:



 
  #15  
Old 03-16-2020, 10:45 AM
bobwhitecar's Avatar
Senior Member
Join Date: Feb 2010
Location: Edgerton, OH
Posts: 155
Likes: 0
Received 0 Likes on 0 Posts
where did you get the crank sensor
 



Quick Reply: 2008 f150 5.4



All times are GMT -4. The time now is 09:22 AM.