replaced oil pump..primed oil pump..will not start now?
11-13-2011 | 07:45 PM
#1
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Newbie
Joined: Sep 2011
Posts: 2
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Model: Cherokee
replaced oil pump..primed oil pump..will not start now?
OK i have a 2000 jeep cherokee sport, replaced motor, ive recently replace the oil pump due to low oil pressure. while i was taking the old one out i noticed a large dent on the oil pan where the oil pump is located. further inspection has shown the oil pump was cracked in two pieces, im guessing something hit the oil pan hard enough to crack the oil pump. anyways, after removing the camshaft position sensor and priming the new pump i replaced the camshaft sensor gear thingy, and it will not crank. The motor will turn over a few times but then stops, seems like the timing is off or something. Any advice will be helpful to get my jeep running once again. 
here is a pic, and yes i know it is unpluged, again ty for your help
here is a pic, and yes i know it is unpluged, again ty for your help
11-13-2011 | 11:37 PM
#2
Senior Member
Joined: Jul 2011
Posts: 731
Likes: 3
There is a procedure for this. They have to be in the exact spot in order for the computer to "see" that the camshaft, and crankshaft postion sensors are in correlation with each other.
I copied the info below off of an "ask a jeep expert" website.
I copied the info below off of an "ask a jeep expert" website.
CAMSHAFT POSITION SENSOR - 4.0L ENGINE
The Camshaft Position Sensor (CMP) on the 4.0L 6 - cylinder engine is bolted to the top of the oil pump drive shaft assembly CMP and Oil Pump Drive Shaft - 4.0L Engine The sensor and drive shaft assembly is located on the right side of the engine near the oil filter CMP Location - 4.0L Engine
The rotational position of oil pump drive determines fuel synchronization only. It does not determine ignition timing.
NOTE: Do not attempt to rotate the oil pump drive to modify ignition timing.
Two different procedures are needed for removal and installation. The first procedure will detail removal and installation of the sensor only. The second procedure will detail removal and installation of the sensor and oil pump drive shaft assembly. The second procedure is to be used if the engine has been disassembled.
An internal oil seal is used in the drive shaft housing that prevents engine oil at the bottom of the sensor. The seal is not serviceable
REMOVAL - SENSOR ONLY
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.
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.
Read more: i am replacing my 4.0 inline six in my 2000 jeep grande cherokee. - JustAnswer http://www.justanswer.com/jeep/1u13l...#ixzz1deR8exb5
The Camshaft Position Sensor (CMP) on the 4.0L 6 - cylinder engine is bolted to the top of the oil pump drive shaft assembly CMP and Oil Pump Drive Shaft - 4.0L Engine The sensor and drive shaft assembly is located on the right side of the engine near the oil filter CMP Location - 4.0L Engine
The rotational position of oil pump drive determines fuel synchronization only. It does not determine ignition timing.
NOTE: Do not attempt to rotate the oil pump drive to modify ignition timing.
Two different procedures are needed for removal and installation. The first procedure will detail removal and installation of the sensor only. The second procedure will detail removal and installation of the sensor and oil pump drive shaft assembly. The second procedure is to be used if the engine has been disassembled.
An internal oil seal is used in the drive shaft housing that prevents engine oil at the bottom of the sensor. The seal is not serviceable
REMOVAL - SENSOR ONLY
- Disconnect electrical connector at CMP sensor CMP Location - 4.0L Engine
- Remove 2 sensor mounting bolts CMP and Oil Pump Drive Shaft - 4.0L Engine or CMP Location - 4.0L Engine
- Remove sensor from oil pump drive.
- Install sensor to oil pump drive.
- Install 2 sensor mounting bolts and tighten to 2 N·m (15 in. lbs.) torque.
- Connect electrical connector to CMP 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.
- Disconnect electrical connector at CMP sensor CMP Location - 4.0L Engine
- Remove 2 sensor mounting bolts CMP and Oil Pump Drive Shaft - 4.0L Engine or CMP Location - 4.0L Engine
- Remove sensor from oil pump drive.
- 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°.
- Remove hold-down bolt and clamp CMP Location - 4.0L Engine
- While pulling assembly from engine, note direction and position of pulse ring CMP and Oil Pump Drive Shaft - 4.0L Engine After removal, look down into top of oil pump and note direction and position of slot at top of oil pump gear.
- Remove and discard old oil pump drive-to-engine block gasket.
- Clean oil pump drive mounting hole area of engine block.
- Install new oil pump drive-to-engine block gasket.
- 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 CMP Pulse Ring Alignment - 4.0L Engine
- 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.
- If engine crankshaft or camshaft has been rotated, such as during engine tear-down, CMP sensor relationship must be reestablished.
- Remove ignition coil rail assembly. Refer to Ignition Coil Removal/Installation.
- Remove cylinder number 1 spark plug.
- Hold a finger over the open spark plug hole. Rotate engine at vibration dampener bolt until compression (pressure) is felt.
- 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 Align Timing Marks - 4.0L Engine Always rotate engine in direction of normal rotation. Do not rotate engine backward to align timing marks.
- 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.
- Remove toothpick from housing.
- Install sensor to oil pump drive. After installation, the CMP sensor should face rear of engine 0°.
- Install 2 sensor mounting bolts and tighten to 2 N·m (15 in. lbs.) torque.
- Connect electrical connector to CMP sensor.
- If removed, install spark plug and ignition coil rail.
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.
- Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below and to left of steering column.
- Gain access to SET SYNC screen on DRB.
- Follow directions on DRB screen and start engine. Bring to operating temperature (engine must be in "closed loop" mode)
- 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.
- 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.
- Tighten hold-down clamp bolt to 23 N·m (17 ft. lbs.) torque.
Read more: i am replacing my 4.0 inline six in my 2000 jeep grande cherokee. - JustAnswer http://www.justanswer.com/jeep/1u13l...#ixzz1deR8exb5
11-14-2011 | 08:46 AM
#5
Senior Member
Joined: Nov 2010
Posts: 510
Likes: 3
From: Chadbourn, NC
Year: 88, 89, 93 & 99
Model: Cherokee
Engine: 4.0
Thanks Guys!!! (This is a friend of mine and I'll be helping with this) I put the oil pump in for him Sat and he primed it and ran into this yesterday... This should give us all the info needed to straighten it out 
04-22-2023 | 09:09 PM
#6
Newbie
Joined: Apr 2023
Posts: 2
Likes: 0
2002 4L misfire issue here
Does this procedure only apply if you remove the oil pump drive? Or any time you change the oil pump? I only changed my oil pump, haven't touched the CSP or oil drive.
However, while I was changing pistions I rotated the engine backwards once. Would this cause the can sensor timing to be off?
Here is my post I need help with
https://www.cherokeeforum.com/f5/200...alling-269167/
However, while I was changing pistions I rotated the engine backwards once. Would this cause the can sensor timing to be off?
Here is my post I need help with
https://www.cherokeeforum.com/f5/200...alling-269167/
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