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Thread: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

  1. #1
    Mitsu booster
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    Feb 2010
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    2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    This question is best suited for someone very familiar with how to get the cam timing correct on a 2.4 turbo.

    I have a 2004 2.4 turbo PT Cruiser that was had just about everything done to it but it has poor idle quality. At idle it has a slight or sometimes quite noticeable "rump rump rump rump" to the idle. The car also tends to hesitate somewhat on takeoff. Car drives fine otherwise, gas mileage 20+ combined, no smoke, coolant loss, no codes etc. It will occasionally throw a random engine misfire code if I let it rump rump rump too long. But it's only done it 2-3 times in 6 months of daily driving.

    I bought the car needing a head gasket, went through all that, had the head rebuilt, all new gaskets(intake, exhaust, valve cover, etc.), factory correct spark plugs, factory wires, replaced coil, 140psi in all cylinders, new sensors, looked for vacuum leaks, timing belt water pump tensioner and idler all done when the head was done, injectors cleaned, even swapped...all resulted in no change in idle quality, all done after the head/timing belt job.

    My question is about the precision of the cam timing procedure. Lets say I was one tooth off, either one cam or the other or at the crankshaft cog. When I did the belt, I didn't really have any trouble at all getting the cam marks to line up nor the crankshaft TDC reference mark to point to the alignment mark on the oil pump housing, and I properly set the tensioner. BUT...every reference that I see on how to do the timing belt job shows that you should place the exhaust cam 1/2 tooth off center, clockwise and the crankshaft cog pointer should actually be aligned with the trailing edge of the tooth, not the center. I had the cam marks aligned with each other (not w/the exhaust cam turned slightly clockwise) and the crankshaft cog pointer aligned with the center of the tooth, not the trailing edge....

    Last edited by ILIKESHELBYS; 05-24-2021 at 03:26 PM.

  2. #2
    Mitsu booster
    Join Date
    Feb 2010
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    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    List of repairs done to this car since I purchased it 6 months ago:

    Replace Cylinder Head, Completely rebuilt cylinder head
    Replaced all gaskets top end w/cylinder head replacement
    Replace fuel injectors
    Replace all drive belts
    Replace air filter (K&N)
    Replace thermostat (190*F)
    Replace Oil and Filter (Mobile1 10/30)
    Replace Spark Plugs
    Replace Water pump
    Replace Timing Belt and tensioner and idler pulley
    Replace radiator
    Replace radiator fan
    Replace Battery (26R)
    Replace PCM (GT/HO Spec) P05033292AD
    Replace all turbo oil/coolant lines (good used)
    Replace turbo Inlet Hose
    Replace turbocharger (good used)
    Replace front Oxygen sensor
    Replace rear Oxygen sensor
    Replace ignition coil (New BlueStreak)
    ⦁ Replaced passenger side center engine mount
    ⦁ Replaced passenger side engine torque strut (upper)
    ⦁ Replaced passenger side engine torque strut (lower)


    Post Rebuild Repairs
    ⦁ Replaced Power Steering Pressure Switch 155,000
    ⦁ Replaced fuel gauge illumination bulb 156,000
    ⦁ Install Factory Sirius Radio System 155,000
    ⦁ Replaced Complete Front Strut Assemblies (Moog) 156,500
    ⦁ Replaced Left & Right Front Lower Control arms, ball joint, bushings 156,600
    ⦁ Replaced turbocharger oil return tube to CHRA gasket 156,600
    ⦁ Repaired turbocharger boost/vacuum lines at compressor housing 156,600
    ⦁ Replaced Throttle Position Switch 156,000
    ⦁ Replaced Cam Position Sensor 156,600
    ⦁ Replaced Crankshaft position sensor 156,800
    ⦁ Replaced AC Hose-Low Pressure/Compressor to Evaporator 156,800
    ⦁ Replaced AC Hose Condenser to Evaporator 156,800
    ⦁ Replaced Idle Control Solenoid/Sensor 158,000
    ⦁ Replaced MAP sensor 158,000
    ⦁ Replaced Air intake Charge Temperature Sensor 158,000

  3. #3
    Garrett booster
    Join Date
    Jan 2007
    Location
    Baltimore, MD
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    113

    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    Your exhaust cam is loo low and is one tooth off.

  4. #4
    Mitsu booster
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    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    87blueshelbyz, thanks for your reply.

    Are you saying this because of the picture I included above? That pic is not my engine....it's an illustration of how the FSM indicates you should perform the belt installation.

    I'm trying to wrap my head around why my cam marks do line up - - but it could be wrong. I admit that I went with personal intuition rather that following the steps as suggested.

  5. #5
    Garrett booster
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    Jan 2007
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    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    Yes, I did say your cam timing was off from looking at your picture.

  6. #6
    Mitsu booster
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    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    That pic is not my engine....it's an illustration of how the FSM indicates you should perform the belt installation. When I remove the top inspection cover, my marks are aligned (- -)

  7. #7

    Re: 2.4 Poor Idle Quality, cam timing off 1 tooth maybe?

    I would have to see if I have any pictures from when I did a Jeep 2.4, but my understanding about the leading and trailing on the crank has to do with taking up the slack... Plus the intake cam tends to like to rock clockwise just a little...

    What I recall when I took the front apart, the cam timing marks were straight across from each other with the crank mark lined up to the right edge of the tooth... (looking at the before pictures I took.)

    So in the picture above, if the crank were rotated just a little more counter clockwise, I think it would match what I had to start with.

    That said, I have not yet run the vehicle or street driven it yet...

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