Aug 042016
 

2000 Jeep Grand Cherokee LaredoI was driving down the road in my 2000 Jeep Grand Cherokee Laredo 4.7 L V8 Power Tech. It lost power, backfired and stopped running. I thought the timing chain broke . I pulled it home and took it apart to see the timing chain. It has 3 chains, the left and front chains are tight and the right chain is a little loose. I can move the loose chain about a 1/2 inch . So can you help me please.


RESPONSE

MEASURING TIMING CHAIN WEAR

NOTE: This procedure must be performed with the timing chain cover removed.

measuring timing chain 4.7 engine Jeep Grand Cherokee

  1. Remove the timing chain cover.
  2. To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston extension is obtained. Measure the distance between the secondary timing chain tensioner housing and the step ledge on the piston.
  3. The measurement at point (A) must be less than 15mm (.5906 inches)
  4. If the measurement exceeds the specification the secondary timing chains are worn and require replacement.

ENGINE TIMING – VERIFICATION

CAUTION: The 4.7L is a non free-wheeling design engine. It is an interference engine. Therefore, correct engine timing is critical.

NOTE: Components referred to as left hand or right hand are as viewed from the drivers position inside the vehicle.

NOTE: The blue link plates on the chains and the dots on the camshaft drive sprockets may not line up during the timing verification procedure. The blue link plates are lined up with the sprocket dots only when re-timing the complete timing drive. Once the timing drive is rotated blue link-to-dot alignment is no longer valid.

Engine base timing can be verified by the following procedure:

timing marks 4.7L engine Jeep Grand Cherokee

  1. Remove the cylinder head covers.
  2. Using a mirror, locate the TDC arrow on the front cover. Rotate the crankshaft until the mark on the crankshaft damper is aligned with the TDC arrow on the front cover. The engine is now at TDC
  3. Note the location of the V8 mark stamped into the camshaft drive gear. If the V8 mark on each camshaft drive gear is at the twelve o’clock position, the engine is at TDC on the exhaust stroke. If the V8 mark on each gear is at the six o’clock position, the engine is at TDC on the compression stroke
  4. If both of the camshaft drive gears are off in the same or opposite directions, the primary chain or both secondary chains are at fault.
  5. If only one of the camshaft drive gears is off and the other is correct, the problem is confined to one secondary chain.
  6. If both camshaft drive gear V8 marks are at the twelve o’clock or the six o’ clock position the engine base timing is correct. Reinstall the cylinder head covers.

timing chain marks 4.7 engine Jeep Grand Cherokee

Engine Warm-Up Mode This is an open loop mode. The PCM adjusts injector pulse width and controls injector synchronization by controlling the fuel injectors ground paths. The PCM adjusts ignition timing and engine idle speed. The PCM adjusts the idle speed by controlling the idle air control motor.

Engine Timing The PCM cannot detect an incorrectly indexed timing chain, camshaft sprocket, or crankshaft sprocket. The PCM also cannot detect an incorrectly indexed distributor.(*)

Aug 042016
 

1997 Jeep WranglerI have removed the skid plate on my 1997 Jeep Wrangler SE 2.5 l 4 cylinder 5 speed manual many times without issue. This time when I went to take it off the transmission wants to come down with it. As far as I know there is not a top transmission mount? what is letting it come down?


RESPONSE

There is no top transmission mounts, you are correct about that. There are two engine mounts and one transmission mount. It is normal for the transmission to want to lower. You should place something under it to support it when removing the skid plate.

skid plate 1997 Jeep Wrangler

TRANSFER CASE SKID PLATE

The transmission and transfer case crossmember is integrated with the transfer case skid plate.

REMOVAL

WARNING: THE TRANSFER CASE AND TRANSMISSION ARE SUPPORTED BY THE TRANSFER CASE SKID PLATE. BEFORE REMOVING THE TRANSFER CASE SKID PLATE, ENSURE THAT THE TRANSMISSION IS PROPERLY SUPPORTED.

  1. Raise and support the vehicle.
  2. Place a support under the transmission.
  3. Remove the nuts attaching the transmission mount to the skid plate
  4. Remove the bolts attaching the skid plate to the frame
  5. Separate the skid plate from the vehicle.

INSTALLATION

  1. Position the skid plate on the vehicle.
  2. Install the bolts attaching the skid plate to the frame. Tighten the bolts to 74 N·m ( 55 ft. lbs.) torque.
  3. Install the nuts attaching the transmission mount to the skid plate. Tighten the nuts to 28 N·m ( 21 ft. lbs.) torque.
  4. Remove the support under the transmission.
  5. Remove the support from under the vehicle and lower the vehicle.
Aug 012016
 

Jeep LibertySo, there is a leak in the boot from the rack to the tie rod on my Jeep Liberty.  I’m just wondering if its an indication of a bigger problem with the tie rod or the rack or if its just a hole in the boot?


RESPONSE

All the boots have a hole in them. This allows them to move without having an issue with air pressure. The boot is to help assist in keeping dust and dirt away from the seals in the rack. It is safe to drive with a small leak as long as you keep the fluid level topped off. Letting it run dry will damage the power steering pump. If the leaks gets bad enough to warrant fixing it. Replacing the entire rack is normal. An alignment will be needed once the repair is completed.

Labor time for replacing the rack is between 3 and 4 hours. Not including the alignment.

Jul 182016
 

2005 Jeep Grand CherokeeDuring deceleration at about 30mph and below there’s a loud ticking noise what sounds like from the rear. If I accelerate it seems to stop. Any ideas what this rear end noise could be?


RESPONSE

This is most likely coming from the rear differential. Specifically the pinion shaft bearings. Drain a little rear end fluid and look for the gear oil to has a shinny tint. You may also notice tiny metal flakes. This is from the bearings breaking down and will cause a rear end noise.

rear end noise

Once the bearings are replaced the differential bearing preload and gear backlash need to be adjusted to proper specifications.

 

  • Install new collapsible spacer (1) on pinion gear and install pinion in housing.
  • Tap pinion flange onto the pinion.
  • Install flange washer and a new nut on pinion and tighten pinion nut until there is zero end-play.
  • With a torque wrench and Flange Wrench C-3281 tighten the pinion nut to 285 N·m (210 ft. lbs.).NOTE: Do not exceed the minimum torque 285 N·m (210 ft. lbs.) when installing the pinion nut at this point.

Pinion shaft bearing installation

  • Measure pinion torque to rotating (1) with an inch pound torque wrench (2). Measure pinion torque to rotating frequently to avoid over over-crushing the collapsible spacer.Pinion Torque To Rotate is:
  • Original Bearings: 1 – 2 N·m (10 – 20 in. lbs.)
  • New Bearings: 1.7 – 4 N·m (15 – 35 in. lbs.)

If pinion torque to rotate is low, tighten pinion nut in 6.8 N·m (5 ft. lbs.) increments until pinion torque to rotate is achieved.

CAUTION: Never loosen pinion nut to decrease pinion bearing rotating torque. If pinion torque to rotating is exceeded a new collapsible spacer must be installed. Failure to follow these instruction will damage the axle.

Ring gear and pinion are supplied as matched sets. Identifying numbers for the ring gear and pinion are painted onto the pinion gear shaft and the side of the ring gear. A plus (+) number, minus (–) number or zero (0) along with the gear set sequence number (2) (01 to 99) is on each gear. This first number (1) the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion marked with a (0). The next two numbers are the sequence number of the gear set. The standard depth provides the best teeth contact pattern.

 

Jun 272016
 

U-joints 2010 Jeep WrangerOn my 2010 Jeep Wrangler whenever I engage the 4×4, and make a hard turn the wheel rattles.


RESPONSE

I would have to say that the axles u-joints or the hub bearings are worn. I would lean more toward the axles  u-joints as the hub bearings would tend to be noisy in 2WD or 4WD.

Axle Shaft Removal

 

  • With transmission in neutral, position vehicle on hoist.
  • Remove brake components.
  • Remove wheel speed sensor from hub bearing.
  • Remove hub nut (1) from axle shaft (2).
  • Remove three hub bearing bolts (1) from steering knuckle (2).
  • Remove hub bearing (1) with axle shaft (2) through steering knuckle.

axle shaft 2010 Jeep Wrangler

  • Remove brake shield and hub bearing from axle.

Pressing a two-way momentary rocker switch on the switch bank request axle lock. The first press DOWN requests rear axle to be locked, every other press DOWN toggles between “front and rear axle lock” and “rear axle lock” request states. Press rocker switch UP requests both axles to be unlocked. The switch is on the IP in the switch bank. The switch bank sends a message to the Cabin Cluster Node (CCN). The CCN handles the switch debounce and switch diagnostics. Any one message sent by the CCN on the network is a valid switch change. The CCN passes the information to the Totally Integrated Power Module (TIPM) via a CAN B message. The TIPM will process the switch info received from CAN B, control the outputs as required by the Axle Lock Electrical Requirements, and send a lighting request to the CCN via CAN B. There are three telltales on the cluster, “Rear”, “Front”, and “Lock”. The telltales will be off if the axles are unlocked, flashing if there is a pending request to lock but the axles are not yet locked (transition to lock, torque-locked, or conditions not correct), and flashing rapidly if there is a fault. The “Front” and “Rear” telltales will match the front and rear differential states. The “Lock” telltale will be on solid if either the “Front” or “Rear” telltale is on or blinking. The TIPM will send the axle lock status message to the ESP module via CAN C.

 

Jun 242016
 

Ignition Control Module 1987 Jeep CherokeeThe problem started when turning right. The engine would cut out like it was out of gas. Sometimes it would die, but start right back up. Now its happening just driving down the road. We changed the fuel filter, that did not help. Don’t know what to check now?


RESPONSE

90% certain it is the ignition control module. This is a common failure part for this model.

Ignition Control Module Replacement

 

  • Remove the distributor cap and rotor.
  • Disconnect the harness connector and pick-up coil spade connectors from the module. Be careful not to damage the wires when removing the connector.
  • Remove the two screws and module from the distributor housing.
  • Coat the bottom of the new module with dielectric silicone lubricant. This is usually supplied with the new module. Reverse the above procedure to install.

1991–98 Jeep vehicles are not equipped with an ignition control module. However, the functions of the ignition control module are performed by the Electronic Control Unit (ECU), also known as the Powertrain Control Module (PCM).

 

 

Jun 242016
 

1995 Jeep Grand Cherokee LaredoHello, I need some help. I have a 1995 jeep grand Cherokee Laredo 5.2. My Jeep blows heat out of my defroster only when I turn the knob to change to vent. It still blows out defroster I found a vacuum line had came off my vacuum reservoir. I put it back on and still blows out defroster. I also noticed when my knob is on defroster I can turn it clockwise off defroster and it shuts off system instead of turning all way back to off is the switch control system bad.


RESPONSE

It is possible that the control head is faulty. I do not think a vacuum leak would cause an issue. The reason would be that Defrost is the default location for the airflow door. There is no vacuum applied when the mode switch is placed in the Defrost position.

How the Defrost, Floor, and Panel airflow operates on a manual system vs. Automatic Climate Control

The mode switch is used to direct output airflow. There are 5 different modes of operation: panel, bi-level, floor, floor/defrost and defrost. Different modes of operation are identified by symbols on the control panel. The switch controls vacuum signals to operate the air outlet doors.

1995 Jeep Cherokee Vacumm chart

Jun 222016
 

2003 Jeep LibertyWhat is wrong or which gaskets have failed when; antifreeze in the oil pan, coolant escapes from the system when car is parked and not running. NO white smoke out tailpipe when car is idling or driving. I have a 2003 Jeep Liberty with a 3.7L engine.


RESPONSE

Coolant is under pressure. Generally between 15 – 17 lbs. while the engine is running. The pressure remains in the system for a while even after the engine is turned off. Failed gaskets that would allow coolant into the oil pan would be the intake manifold gasket and or head gasket. At an extreme but not as likely would be a cracked head or block. This usually only happens in extreme overheating situations where someone overheated the engine and continued to operate the vehicle.

Drain the oil into a clean plastic milk jug, let it set for about 4 hours, You will see if there is any coolant present. It will readily show itself.

2003 Jeep Liberty TSB – Technical Service Bulletins

Did not find any TSB’s  on this issue.

Jun 202016
 

1997 Jeep WranglerIt starts and idles great. When I try to drive it, it stalls and cuts out. Then it takes a min to start back up. Recent Mopar brain replacement. Thinking TPS or Fuel Pump. Ideas?


RESPONSE

I’m thinking fuel pump or MAP – Manifold Absolute Pressure Sensor. You can check you codes if any. Most times when a MAP sensor is faulty it will not set a code. It will be stuck and send the same signal that is within the allotted parameters. You can check the fuel pressure with a fuel pressure gauge. See if the fuel pressure drops when you try to accelerate. Good pressure at idle and bad on acceleration would indicate a faulty fuel pressure regulator. Of course bad fuel pressure at idle would indicate a clogged fuel filter or faulty fuel pump.