Little Jeep that wouldnt start

Discussion in 'Shop Talk' started by HermitJohn, Dec 28, 2006.

  1. HermitJohn

    HermitJohn Well-Known Member

    Messages:
    8,516
    Joined:
    May 10, 2002
    I avoid modern stuff best I can, but guy I know wanted me to look at his '89 Cherokee (compact). Well, he had one of those consumer car manuals edited by lawyers that try their darndest not to give any useful information. But finally found ignition module. Took it to O'Reillys and their machine couldnt test it and they could order it for mere $128. AutoZone could test it and it was bad. They had one in stock that was around $90. Had them test it before friend bought it (I've shopped at AutoZone before) and it tested ok. Put it in and nothing.

    Well Google is our friend and found these Jeeps have crankshaft positioning sensor that gives problems. Simple test though, unplug it from wiring harness, plug it back in and voila, Jeep, nine times out ten will start. I did and it did. Now advice from internet said to replace CPS when it acted up like this. And they suggest getting new one from dealer rather than parts store.

    My question is could a bad ignition module cause this and the unplugging/replugging of CPS simply resets it and that is good enough or does CPS have to be replaced (dont know if I can get my hand back into there to remove old CPS bolts as newer cars require a double jointed midget mechanic to work on them...).

    By way how long have I been asleep to find out that there are now few hundred different ignition modules out there and most are no longer $20? Ah, another Rip Van Winkle moment......
     
  2. Herb

    Herb Well-Known Member

    Messages:
    120
    Joined:
    Jun 24, 2006
    I will try this again.
    I agree that the CPS is probably bad. I had one go bad on my 92 Olds. The car wouldn't start, so a mechanic told me to peck on the CPS with a long screwdriver, then try to start it. It started up just fine. Then he told me to peck on it while the motor was running; the motor started to stumble.
    I don't think that the ignition module going bad could cause the CPS to go bad. The both tie into the computer, but aren't connected. The CPS tells the computer where the #1 piston is and the computer uses that info to set the time for the motor.
    I replaced my CPS with one I bought from Autozone. I have always had the opinion that the same manufacture makes the same part for the stealership and the parts store.
     

  3. HermitJohn

    HermitJohn Well-Known Member

    Messages:
    8,516
    Joined:
    May 10, 2002
    I guess all other posts disappeared with the forum problems. I just found it odd that both the module and the CPS went at same time. By way the original ignition module said "made in France" on it. Somehow bet the slimmer looking replacement was Mexican or Chinese. Never know though, the replacement rear brake drums on my Ranger came from Argentina.
     
  4. Herb

    Herb Well-Known Member

    Messages:
    120
    Joined:
    Jun 24, 2006
    I also replaced the ignition module on my Olds before I even knew about the CPS. I never had mine tested though, I just assumed it was bad (that was $100.00 down the drain).

    Another story for the stealership vs. parts store.
    I also own a 2000 F-150. It started to misfire when it had about 80,000 miles on it. I decided to go ahead and change the spark plugs (PITA to change, but that is another rant) and do a tune up. I get all of the plugs changed, but I still have the misfire. But now my SES light is on and I pull a code. I can't remeber the exact code, but it was for "Cylinder #5 COP". The truck has 8 ignition coils. There are Coil On Plug or COP. They sit directly on top of the spark plug and plug into a wiring harness. I did some research and everything I found said it was a dealer only item. I called the stealership and they said they were $50.00 each, but I had to buy all eight. Total price $400.00. On a whim, I call Advance Auto and they said they carried them and they were $38.00 each. So I go down to Advance Auto and tell them I need 8. The clerk looked at me and said why 8, I could just buy 1 if I needed it. Boy was I a happy camper.
    After I removed the bad one, I peeled off the Motorcraft sticker on the top of the COP and it had the same part number of the COP I bought at Advance Auto
     
  5. jefferson

    jefferson fuzzball in the Cascades

    Messages:
    639
    Joined:
    Nov 11, 2004
    Location:
    State of Jefferson
    France!!! ! Well there is your answer. Change that part out