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  #1  
Old October 12th, 2007, 17:49
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RANSOM RANSOM is offline
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HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

Ok here's the deal. 2000 XJ, 4.0, auto. I over-heated it causing the head to crack and let it go for awhile...(duh!) It developed a rod knock. So I took my friends 1997 engine (that only had 90,000 miles and ran perfect) and I put a new 2000 head on it and dropped it in.

It has a rough idle and sometimes it stalls.

2000 xj's run coil packs, so where the distibutor once was, there's just a camshaft position sensor. I read in the service manual that once the cps is taken out, they have to be re-set or re-timed. The engine runs beautiful as soon as you take it up off idle. I've tried to adjust the cps hoping to clear up the this rough idle. But it just won't clear up. I've checked for vaccuum leaks---none. It has brand new plugs, timing chain & gears.

Here's my question:
Is my problem the cps adjustment or is there something I'm over-looking???

Any help would be greatly appriciated.

-Ransom
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Old October 12th, 2007, 18:29
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kdailey4315 kdailey4315 is offline
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

I hope you didn't put back an 0331 casting 2000 head. If you did expect it to crack again. If it ran perfect how come you changed the head?
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Old October 12th, 2007, 19:12
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Hellbent Hellbent is offline
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

if by "cps" you mean cam position sensor(most people mean crank position), then yes, there is a procedure that you have to follow to "re-time" it. from what i understand, it can cause a no-start or miss/stumble if it's not reset. if you need the procedure and can't find it, let me know. i'm sure i can find it again.
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Old October 12th, 2007, 19:20
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Hellbent Hellbent is offline
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

here you go:


REMOVAL - OIL PUMP DRIVE AND SENSOR

If the CMP and oil pump drive are to be removed and installed, do not allow engine crankshaft or camshaft to rotate. CMP sensor relationship will be lost.
  1. Disconnect electrical connector at CMP sensor
  2. Remove sensor from oil pump drive.
  3. Before proceeding to next step, mark and note rotational position of oil pump drive in relationship to engine block. After installation, the CMP sensor should face rear of engine 0.
  4. Remove hold-down bolt and clamp
  5. While pulling assembly from engine, note direction and position of pulse ring After removal, look down into top of oil pump and note direction and position of slot at top of oil pump gear.
  6. Remove and discard old oil pump drive-to-engine block gasket.
INSTALLATION - OIL PUMP DRIVE AND SENSOR
  1. Clean oil pump drive mounting hole area of engine block.
  2. Install new oil pump drive-to-engine block gasket.
  3. Temporarily install a toothpick or similar tool through access hole at side of oil pump drive housing. Align toothpick into mating hole on pulse ring.
  4. Install oil pump drive into engine while aligning into slot on oil pump. Rotate oil pump drive back to its original position and install hold-down clamp and bolt. Finger tighten bolt. Do not do a final tightening of bolt at this time.
  5. If engine crankshaft or camshaft has been rotated, such as during engine tear-down, CMP sensor relationship must be reestablished.
    1. Remove ignition coil rail assembly. Refer to Ignition Coil Removal/Installation.
    2. Remove cylinder number 1 spark plug.
    3. Hold a finger over the open spark plug hole. Rotate engine at vibration dampener bolt until compression (pressure) is felt.
    4. Slowly continue to rotate engine. Do this until timing index mark on vibration damper pulley aligns with top dead center (TDC) mark (0 degree) on timing degree scale. Always rotate engine in direction of normal rotation. Do not rotate engine backward to align timing marks.
    5. Install oil pump drive into engine while aligning into slot on oil pump. If pump drive will not drop down flush to engine block, the oil pump slot is not aligned. Remove oil pump drive and align slot in oil pump to shaft at bottom of drive. Install into engine. Rotate oil pump drive back to its original position and install hold-down clamp and bolt. Finger tighten bolt. Do not do a final tightening of bolt at this time.
    6. Remove toothpick from housing.
  6. Install sensor to oil pump drive. After installation, the CMP sensor should face rear of engine 0.
  7. Install 2 sensor mounting bolts and tighten to 2 Nm (15 in. lbs.) torque.
  8. Connect electrical connector to CMP sensor.
  9. If removed, install spark plug and ignition coil rail.
To verify correct rotational position of oil pump drive, the DRB scan tool must be used.
WARNING: WHEN PERFORMING THE FOLLOWING TEST, THE ENGINE WILL BE RUNNING. BE CAREFUL NOT TO STAND IN LINE WITH THE FAN BLADES OR FAN BELT. DO NOT WEAR LOOSE CLOTHING.
  1. Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below and to left of steering column.
  2. Gain access to SET SYNC screen on DRB.
  3. Follow directions on DRB screen and start engine. Bring to operating temperature (engine must be in "closed loop" mode)
  4. With engine running at idle speed, the words IN RANGE should appear on screen along with 0. This indicates correct position of oil pump drive.
  5. If a plus (+) or a minus (-) is displayed next to degree number, and/or the degree displayed is not zero, loosen but do not remove hold-down clamp bolt. Rotate oil pump drive until IN RANGE appears on screen. Continue to rotate oil pump drive until achieving as close to 0 as possible.
The degree scale on SET SYNC screen of DRB is referring to fuel synchronization only. It is not referring to ignition timing. Because of this, do not attempt to adjust ignition timing using this method. Rotating oil pump drive will have no effect on ignition timing. All ignition timing values are controlled by powertrain control module (PCM)
  1. Tighten hold-down clamp bolt to 23 Nm (17 ft. lbs.) torque.
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Old October 13th, 2007, 06:40
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

Thanks. I'll try it.
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Old October 13th, 2007, 08:06
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

Quote:
Originally Posted by kdailey4315
I hope you didn't put back an 0331 casting 2000 head. If you did expect it to crack again. If it ran perfect how come you changed the head?
Yeah, because EVERY 2000 head has cracked.....except mine which has 150K on it and is perfect....

You should be fine with it - it was a small batch of them that must have had a bad casting or flaw that caused them to crack. but there are THOUSANDS of 2000XJs out there with original heads and probably at least 100K miles on them...
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Old October 14th, 2007, 07:08
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RANSOM RANSOM is offline
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Re: HELLLLLLLP!!! Stumble at idle. Pulling my hair out!!!

The cam sensor is set. But it still has a rough idle. The mechanic who helped me out said it's acting like it has a tight valve... But they're non-adjustable. I reused the pushrods out of the motor that I put in. The engine was laying around for awhile getting tossed here and there.

Is it possible that it has a bent pushrod? Another thought... I never removed the crank sensor when I swapped engines. It on has about 10,000 miles on it. Is it possible that it got bumped during the swap causing it to intermitently fail?
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