Mj wont start after Ax15 Swap...

  • 1988 - 4.0L-Ba10-4x4...
    I have a new Luk LFW194 flywheel installed. Was my daily
    before the swap. When old CPS did not work, replaced with
    new one - no change. Motor cranks and I have fuel and spark.
    The only thing odd about this swap (besides the never ending
    array of headaches) is that the strap I had holding the motor
    level broke the first day - the motor sat tilted back for the
    three weeks its taken to put in the new Ax15.
    If I have to dig back into the transmission I'm calling it
    quits on repair/fit and leaving her sit until Im ready for the
    rebuild. I'm hoping theres something obvious I missed, but I
    dont see any random plugs sitting loose, and from what ive
    read/been told there are no other switches/sensors besides the
    CPS that would prevent it from starting...
    Any ideas? I have a parts run Sat morning, but I have all
    afternoon to pick at issues....

  • Pretty sure there is also a dist sync sensor. Both it and the cps will cause a no start. Im also assuming u have check all the fuses. R u sure u have the correct flywheel. Pretty sure the renix fi is different from the ho one.


    Thinking about it a little more if the cps was not working u would not even get spark. Does it sound like a timing issue?

  • [size=2]Yes, there are 2 cps's; a crank position sensor and a cam position sensor. The cam position sensor is in the distributor. When you pull the distributor cap off it will look like a black plastic disc sitting just underneath.[/size] [size=2] Mine (from a '93 4L) has 3 wires going to it I think. After the wiring harness connector, I believe one goes to the coil, one is ground, and one goes to the computer (I think that one is orange). Check that as well as the plastic adapters that tie it into the harness for integrity. The plastic clip on my connector broke off and unplugged once. Didn't discover that until a few days after pulling my hair out (only the gray ones). [/size] :innocent:

    Member since 2000

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  • Did the timing nibs on the new one look the same as the original?


    Along the lines of what Arron said:


    "The injection flywheel must match the injection system your using, the renix flywheel has twice or three times as many peckers on it than the OBD flywheel does."


    You would still get spark, but the timing would be wrong.

  • At this point Aaron Im clueless. Spent the day driving around
    picking up parts so I didnt have a chance to look at it like id hope,
    but I'll start the systematic search here in a couple of hours. After
    all the hell Ive been through with this "easy" trans upgrade I was
    hoping it would be something like "did you remember to plug the
    snapoid back into the widget..." But alas...

    Right now the main sysmtom is that besides the failing Ba10 it
    was running fine before I started working, now all it does is crank.
    No fire at all, but after a few tries I can smell fuel like its flooding.
    I'll recheck the spark in a few hours and let you know...


  • Unless I missed something you still haven't answered
    the question about flywheel you used. Did you retain
    the factory flywheel or swap to a different one?


    The new flywheel is a LuK LFW194. Its the correct part
    number and it looked exactly like the OEM, but with no
    engraved numbers on it i have no way of knowing (now)
    if it was the right one...

  • Well by the pics online it looks like the correct flywheel. My bet if u have no spark then its either the cps system, a fuse or the computer. If the check engine light comes on when u first turn the key that usually means the comuter is alive. There r test proceedures out there for a cps. U may have to look them up. Also there r occasions when the cps is not reading the flywheel because its too far away.

  • When i run a voltmeter over the CPS while cranking
    i get a 0.01 reading that holds steady. My understanding
    Is that it should go 0.01, 0.04, 0.01, ect... to show its
    reading the flywheel.



    Question - is it possible nethier CPS is reading the
    flywheel because theyre not close enough? And if
    so, how does one adjust the CPS on the bellhousing?


  • On the TJ the CPS is slotted to allow adjustment.


    On the one that replaced it came with like a piece of masking tape and a paper shim on it that was used as the clearance gauge.


    Looks like it should be about .030".

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