cam/crank sensors - Jeep Commander Forums: Jeep Commander Forum
General Commander Discussion General Discussion involving the Jeep Commander goes here. If it does not fit into a more specific category below, post it here.

 
LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old 07-29-2014, 04:19 PM Thread Starter
Junior Member
Points: 108, Level: 2 Points: 108, Level: 2 Points: 108, Level: 2
Level up: 16% Level up: 16% Level up: 16%
Activity: 0% Activity: 0% Activity: 0%
 
Join Date: Jun 2014
Posts: 7
cam/crank sensors

Anybody know approximately how much a shop would charge to sync cam and crank position sensors?
paulio is offline  
Sponsored Links
Advertisement
 
post #2 of 3 (permalink) Old 07-30-2014, 07:06 AM
Senior Member
Points: 7,723, Level: 58 Points: 7,723, Level: 58 Points: 7,723, Level: 58
Level up: 87% Level up: 87% Level up: 87%
Activity: 0% Activity: 0% Activity: 0%
 
Askbob's Avatar
 
Join Date: Dec 2009
Location: Shelbyville, KY
Own a Commander?: Yes
Model year: 2007
Trim Package: Limited
Power-Train: 5.7L V-8 Hemi
4WD
If 4WD - system: QD-II
Current Mileage: 207800
Posts: 103
Garage
No need to sync. Replace and roll on.
Askbob is offline  
post #3 of 3 (permalink) Old 07-30-2014, 08:05 AM
Senior Member
Points: 15,906, Level: 81 Points: 15,906, Level: 81 Points: 15,906, Level: 81
Level up: 12% Level up: 12% Level up: 12%
Activity: 0% Activity: 0% Activity: 0%
 
Mongo's Avatar
 
Join Date: Oct 2010
Location: Lusby, MD
Posts: 3,037
You don't sync those sensors, those sensors are there to sync the electronic engine management to the engine, the electronic engine management syncs itself. The engine is synched mechanically. So if you have something out of sync, at least bad enough that it is noticeable, it has to be a mechanical failure in the engine.

Of course a sensor going bad or a malfunction may give you the impression something is out of sync.

Everything is synced off the Crank Position Sensor, but the Crank makes 2 rotations before you go through all 4 cycles of a 4 cycle engine. So how does the engine computer know if the cylinder that is going to fire the spark plug, if its on its compression stroke or exhaust stroke, or to open the fuel injector, is it on its intake stroke of its power stroke? The Cam only makes 1 rotation per every 2 Crank rotations, so their is a Cam Position Sensor that just tells the engine computer which of the 2 rotations the Crank is on, so the engine computer can sync itself.

A bad Crank Position Sensor (CPS) and the motor won't run, it doesn't know when to fire the spark plugs or fuel injectors.

But a bad Cam Position Sensor, depending on the motor, it may run it may NOT. Many motors have wasted spark ignitions, that fire the plugs on every rotation, so the syncing of the engine computer is just for the injectors. No signal from the Cam Position Sensor, the engine computer will guess and it has a 50/50 shot. If it guesses right, the motor runs fine, if it guesses wrong, the motor may run, but the injectors are opening at the wrong time and its running of fuel pooled in the intake, so it runs crappy, until you shut it off and start again.

A good place to start is to check the stored Diagnostic Trouble Codes, you can do a youtube search to watch a quick video on how to do the "key dance" to get the instrument vehicle information center (EVIC) to read out the stored codes.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Mongo is offline  
Sponsored Links
Advertisement
 
Reply

  Jeep Commander Forums: Jeep Commander Forum > Jeep Commander Discussion > General Commander Discussion

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Jeep Commander Forums: Jeep Commander 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:
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:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not 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

 
For the best viewing experience please update your browser to Google Chrome