P0279 cylinder 7 injector circuit low...bummer - Ford Powerstroke Diesel Forum
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 03-15-2010, 05:49 PM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
P0279 cylinder 7 injector circuit low...bummer

Is this something i can fix myself? Truck wouldnt start couple weeks ago so i did the FICM re solder trick it worked awesome!!!

But now the injector problem. Im not sure what to test. Thanks for any help.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 03-15-2010, 08:04 PM
Slacker



 

Join Date: Dec 2006
Location: Surprise, Arizona
Posts: 16,719
Thanks: 13
Thanked 11 Times in 9 Posts
Feedback Score: 4 reviews
Check your cables leading from your FICM to your injectors. One of them is shorting out.
Reply With Quote Quick reply to this message
  #3  
Old 03-15-2010, 08:07 PM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
ok ok cool deal!!! sorry if stupid question but the wire is shorting..? a loose connection would be different code or problem?
Reply With Quote Quick reply to this message
  #4  
Old 03-16-2010, 04:45 AM
Compression Ignition Addict
 

Join Date: Dec 2008
Location: port arthur texas
Posts: 3,259
Thanks: 0
Thanked 11 Times in 11 Posts
Feedback Score: 0 reviews
What a short is

Bear in mind there are different kinds/degrees of shorts.
The most familiar is the massive short that blows the fuze. You can have a small short,say just a few or 1 strand of wire touching ground or another wire. This situation will not cause the fuze to blow but will allow part of the voltage to be drawn away from the normal circuit path.

Now every sensor has a wire that carries a reference voltage, the computer knows which reference voltage is for each sensor. For example the reference voltage is 5v but part is being bled off to ground and only 3v is getting there, the computer reads this and throws a code relateing to voltage being low or out of range or some such.

Hope this clarifies some
Reply With Quote Quick reply to this message
  #5  
Old 03-16-2010, 05:37 AM
Slacker



 

Join Date: Dec 2006
Location: Surprise, Arizona
Posts: 16,719
Thanks: 13
Thanked 11 Times in 9 Posts
Feedback Score: 4 reviews
Quote:
Originally Posted by DeadaHead View Post
ok ok cool deal!!! sorry if stupid question but the wire is shorting..? a loose connection would be different code or problem?
Most common occurrence is the wiring has rubbed up against something and now instead of sending the firing voltage to your injector, it shorts out to the chassis. It could also be that your wiring has come loose, but that is a less likely scenario since it is only occurring on one injector. Keep looking because the chafed wiring is sometimes difficult to find. Follow your FICM connections all the way to #7 injector.
Reply With Quote Quick reply to this message
  #6  
Old 03-18-2010, 06:57 AM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Some good info thanks guys!!! If i do find the wire will the check engine light go off or do i need to clear the code with a scan tool?
Reply With Quote Quick reply to this message
  #7  
Old 03-18-2010, 07:17 AM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I think i have an open circuit not a short. REading a FICM guide and it says a short would produce a message that says "injector circuit HIGH" while and open circuit would say "injector circuit LOW"
Reply With Quote Quick reply to this message
  #8  
Old 03-18-2010, 11:20 AM
Slacker



 

Join Date: Dec 2006
Location: Surprise, Arizona
Posts: 16,719
Thanks: 13
Thanked 11 Times in 9 Posts
Feedback Score: 4 reviews
Ah, good catch and you are correct. I apologize I didn't pay close enough attention. Keep us posted on the progress...
Reply With Quote Quick reply to this message
  #9  
Old 03-23-2010, 08:47 AM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Progress sucks!!!! Thought i found and fixed a loose connection where the wires meet the ficm. STarted truck and check engine light was off. So we used the truck to tow a trailer out to the desert this weekend....engine light came back on....truck overheats...hear that whistle that im hoping is the degas cap im reading about.

About to search but anyone have advice to expose the injectors and check for loose wires? Being told they are under the valve cover. I wrecked my dirt bike and effed my back up. Gonna try to wrench on the diesel today so any advice to make it easy will sure be appreciated thanks guys!!!
Reply With Quote Quick reply to this message
  #10  
Old 03-24-2010, 11:19 AM
Member
 

Join Date: Feb 2010
Posts: 31
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
UPDATE: no bueno

Took valve cover and oil rail off. Did not find any loose wires on the #7 injector. Now truck wont start. When cranking over it shows no oil pressure..then after 3 seconds its shows pressure.

Do i need to bleed or prime the oil rail? Any ideas why that sucker wont start for me?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 10:17 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors