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P0172 and P0300

Discussion in 'PT Cruiser' started by dadhelp, Aug 3, 2015.

  1. dadhelp

    dadhelp Active Member

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    Love and Hate it a vicious cycle with My Pt's ! this one is MOM'S 07 Pt Touring 2.4L DOHC n/a auto 150k terrible idle off idle it's fine. marathon back story. poor idle knew coming due for timing belt so it died with milage figured timing belt couldn't work right off so put mom it 02 limited. 6 months pass fast these days! pull covers belt not broke ? test no fuel pump not sure original issue or died from sitting, so gets royal treatment- t/b ,wp all pulleys and tensioner, fuel pump, plugs ,wires and upper gasket set . starts runs great but die when coming back to idle scan show iac not responding correct, clean throttle body off car, install new iac and tps ok idle return good but after idle for minute or two starts to idle erratic and codes with flashing mil, if come off idle clears up mil goes off . visual inspection for vacuum leak and sprayed down with carb clean not vacuum issue. ps old plugs were toast maybe stressed coil . P0172 is 1/1 o2 rich is because it is loading up > going to test install in line spark tester to see if coil dropping out at idle, and fuel pressure but pressure issue would effect all ranges, . open to suggestions . Mom really wants this one back and cant seem to clear this final hurdle! thank you for listening to my rant and your help!
     
  2. ImperialCrown

    Level III Supporter

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    So the rough idle was there before and after the timing belt?
    By 'toast' do you mean that the plugs were carbon-fouled or excessively worn?
    Are they the correct NGK LZTR4A-11 or Champion RE16MC plugs?
    How do the plug tips look now?
    If it is only at idle and the cam timing is 'dead nuts' on the timing marks, I would try a cylinder compression 'leakdown' test. A cylinder compression test by cranking it over, may be too fast to catch a leaky valve.
    Is fuel pressure OK? Has the O2 sensor been replaced with an OEM sensor?
     
  3. dadhelp

    dadhelp Active Member

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    my appologies for not posting solution guess completion and new life drama it slipped my mind . with closer inspection with a mirror and bright light for my blind eyes . the cam marks were off now this befuddled me! So i disassembled timing covers to reset . like I said it was dead on when we assembled it, two old fools looked at it , but instead of proper tool to hold while loosening pulleys a bar appeared to hold fine but had cracked the rear timing cover and a piece fell out after assembly and made it apparently around the crank pulley and wedged into belt, as it entered cam pulley it slipped a tooth is the only explanation for hole cut in center of brand new belt and the improper mark alignment .pulled all pullies replaced broken rear timing cover and new damaged belt with a new undamaged belt runs like a top! moral of the story use the proper tool , and just cause you saw it with your own eyes when you assembled it isn't an absolute ! thanks for all your help and suggestion refreshing to have a forum that its not days before someone reponds to your question or bombarded with shear craziness you are a great asset to the morepower community
     
    ImperialCrown likes this.
  4. ImperialCrown

    Level III Supporter

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    The timing belt can go on the pulleys and look 'dead nuts' on the timing marks. This can be deceiving.
    It is only when the crankshaft is turned over 2 revolutions to settle and center the belt path, that one discovers that the marks no longer exactly line up.
    I'm glad that you found the problem.
     
    djsamuel likes this.

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