Hello, Allpar Forums member or visitor! If you were a member, you would not see this ad!

Register or log in at the top right of the page...

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

2002 Jeep Liberty No pulse injectors - new PCM and reman motor

Discussion in 'Cherokee, Liberty, Nitro' started by tcsports, Dec 19, 2016.

  1. tcsports

    tcsports New Member

    Joined:
    Dec 19, 2016
    Messages:
    3
    Likes:
    0
    I have a 2002 Jeep Liberty. my original engine blew a rod. I bought an reman engine. I had to send the engine back twice first for a wrist (sp) pin failing and second time for not being in time correctly. the original install everything work until the wrist pin (gear) went. the 2nd install had the timing problem. the 3rd install has no pulse to the injectors a cam sensor code was showing. (the cam sensor has been replaced 4 times BTW - after the first time the code showed) I took it to a dealership now a new PCM was installed and still no pulse. any and all help is appreciated.

    thanks
     
  2. ImperialCrown

    Level III Supporter

    Joined:
    Jun 8, 2008
    Messages:
    18,221
    Likes:
    2,653
    Welcome to Allpar. Is the engine now in it from 2002-2003?
    There was a major change in cam/crank sensor relationship when the later NGC (next generation controller) PCM came out.
    The crankshaft position and cam sprocket trigger wheels (reluctors) had a different tooth count and tooth positions.
    Edited to correct videos:

     
  3. tcsports

    tcsports New Member

    Joined:
    Dec 19, 2016
    Messages:
    3
    Likes:
    0
    From everything I can find out it is a 2002 engine. it has the JTEC cam sprocket I am currently waiting on the tooth count to see if it's a 16 tooth as needed or 32.
     
  4. tcsports

    tcsports New Member

    Joined:
    Dec 19, 2016
    Messages:
    3
    Likes:
    0
    Ok, I'm confused I been told the the reluctor has only 12 tooths. Has there ever been a 12 tooth 3.7? My understanding is 02-03 has a 16 tooth reluctor ring and 04-06 had 32 tooth reluctor ring. This has been a very strange I'm totally confused by this 12 tooth reluctor ring.
     
  5. ImperialCrown

    Level III Supporter

    Joined:
    Jun 8, 2008
    Messages:
    18,221
    Likes:
    2,653
    I don't know tooth counts, but the SBEC module engine is different than the NGC engine. You may find your answer in a Google search. Some vendors offer sprocket/reluctor wheel kits to convert between SBEC and NGC generation engines.
    Does it run on the cam sensor alone with the crank sensor unplugged? You may have to let it crank over awhile before the PCM knows where #1 TDC is before it catches and runs.
    This was also discussed here with that same video:
    How Chrysler programs its ECM to function
    It is also discussed here with other engines during the NGC conversion. It doesn't discuss the 3.7L in particular, but covers the same issue:
    Tips and tricks of Chrysler signal relationships | Search Autoparts
    For SBEC (which yours should be), the cam sprocket signal is 1-2-3-1-3-2 and repeats. The crank reluctor signal is 4-4-5-4-4-5 and repeats.
     

Share This Page

Loading...