Kj HELP PLEASE

[ravimehmi0321]

Jeep Liberty (Cherokee) KJ

• 2.8 CRD
• 2007
• Manual
• UK vehicle
• Crank but no start
• Would cough occasionally
• Glow plug light intermittent
• Multiple communication faults originally (BCM/PCM messages not received)

Electrical / Control Side (Ruled Out)

• ECU bench tested (Autotronics) – passes, 5V reference present
• VINs match (PCM / BCM / SKIM)
• No immobiliser active
• Crank signal present (seen on OBD)
• Cam signal now confirmed
• Throttle pedal not responding because engine never enters run state (expected)
• Glow plug module originally floating loose (not grounded)

Grounds Upgraded / Cleaned

• Battery negative → alternator bolt (35mm²)
• Alternator → bulkhead (35mm²)
• ECU ground cleaned
• Bonnet strap replaced
• Temporary jumper lead from engine to battery negative made glow plug light behave more consistently

Electrical faults improved, not worsening.

Glow Plug System

• Original glow plug control module:
  • No audible click
  • Glow light very intermittent
• 
  
• Replacement Bosch module now fitted
• Glow light now:
  • Comes on for ~2 seconds
  • Only returns after key-off rest period

Improvement, but still no start

Fuel System – Current Focus

Observations

• Fuel present at injectors (cracked lines)
• Engine will run briefly on Easy Start → confirms:
  • Compression OK
  • Timing OK
  • ECU can run engine if fuel injected
• 
  
• Engine dies immediately when Easy Start stops

Points to fuel pressure / injection enable issue

Rail Pressure (Live Data)

• While cranking:
  • Ranges from ~150 psi up to 800–950 psi
  • Only reaches higher values when glow plug light appeare
• Does not sustain pressure
• Pressure collapses quickly

Fault Code (New)

• P0093 – Fuel System Large Leak Detected
  • Appeared after recent testing
  • Was not present earlier

Low Pressure Supply Changes

• Hand primer bulb:
  • Goes soft while cranking
  • Loses pressure at rest
• 
  
• Installed HEP-02A low pressure electric lift pump (3–6 PSI)
• Temporarily mounted in engine bay near fuel filter
• Inline filter before pump
• OEM filter still in place

Fuel supply improved but problem persists
Current Symptoms

• No self-start
• Runs only on Easy Start
• P0093 active
• Rail pressure builds but drops
• No RPM shown on dash (RPM visible on OBD)
• BCM overhead display not updating

What Has NOT Been Done Yet (Next Tests

1. PRV (Pressure Relief Valve) leak test
   • Remove return hose from rear of rail
   • Check for fuel during cranking
2. 
   
3. Injector leak-back test
   • Bottle test on injector returns
4. 
   
5. Verify lift pump placement
   • Possibly move pump closer to tank (push vs pull
6. Battery voltage under load
   • Drops to ~10.7V while cranking

 

[Unclebob9]

I have a 2006 crd. Before I bought it I did quite a bit of research. Excellent vehicle in Europe, when Jeep brought them to the USA, they eliminated some parts to cut costs. Mine was a few years old when I bought it and I put many of the parts into mine that the European CRDs have and were left out of ours. One was an in tank fuel pump, I bought a used one out of a Dodge diesel pick-up. As soon as I turned the key I had a leak at the fuel filter, tightening it solved the problem and I no longer have to pump the primer after changing the filter.
It has been 15 or so years since I did it, but the wiring was there, I think I had to hook to it under the back seat?