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sprinkles08
sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 21571
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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My issue is my Jeep wrangler diesel engine 2.8 CRD wont

Customer Question

my issue is my Jeep wrangler diesel engine 2.8 CRD wont start, cranks fine and can push start and start with quick start but not on its own ..??? Have changed fuel pump, injectors, filters,hi-pressure pump, fuel pressure regulators and still wont start. No fault codes either
JA: Thanks. Can you give me any more details about your issue?
Customer: Dave, my issue is my Jeep wrangler diesel engine 2.8 CRD wont start, cranks fine and can push start and start with quick start but not on its own ..??? Have changed fuel pump, injectors, filters,hi-pressure pump, fuel pressure regulators and still wont start. No fault codes either
JA: OK got it. Last thing — Jeep Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 8 months ago.
Category: Jeep
Expert:  sprinkles08 replied 8 months ago.

Hello and welcome to JustAnswer!

The symptoms and lack of fault codes point to low rail pressure. The ECM has to see enough rail pressure when cranking before the injectors will turn on.

Where did the replacement parts come from?

Did the problem start after a repair, contaminated fuel, etc?

Do you have an actual scan tool to monitor data?

Customer: replied 8 months ago.
Problem Started after contaminated fuel.. Parts came from Jeep Dealer. So began fitting new parts even Crank Sensor changed, but stil No start ..?
Customer: replied 8 months ago.
Did have fault codes point to low rail pressure, the replaced Hi-pressure pump on advice of dealer. Still No start. How to keep rail pressure hi as all part new now
Expert:  sprinkles08 replied 8 months ago.

Do you have an actual scan tool to monitor data?

Customer: replied 8 months ago.
I do
Expert:  sprinkles08 replied 8 months ago.

What are rail pressure and setpoint while cranking?

Customer: replied 8 months ago.
Rail pressure at crank is 1.4 bar
Customer: replied 8 months ago.
what causes teh rail pressure to drop ..?
Expert:  sprinkles08 replied 8 months ago.

That's while cranking?

Customer: replied 8 months ago.
while cranking, and sh e fires up at around 1.8 Bar .. What does "setpoint" Mean ..??
Expert:  sprinkles08 replied 8 months ago.

Setpoint is the commanded rail pressure.

There is no chance the engine will run at 1.8 bar, that's 26 PSI. The ECM has to see about 5,000 PSI for the injectors to turn on. Can you double check what you're seeing?

Customer: replied 8 months ago.
Okay I understand now.. was converting incorrectly ... was seeing 1400 psi at crank and assuming it at 1.4bar... SO i can sy with quick start she fires at around 2000 psi.. What would cause low pressure in Rail.. if i have changed everything just as a fault finding exercise..???
Expert:  sprinkles08 replied 8 months ago.

I know that the injectors and high pressure pump have been replaced, what other parts specifically have been replaced?

Customer: replied 8 months ago.
Fuel pump, fuel filter, pressure regulator and Crank sensor - over and above those two. So now i am lost as shoudl not be losing pressure anywhere... and loosk liek waste of money buying all those new parts
Expert:  sprinkles08 replied 8 months ago.

Do you have the part number of what you're referring to as the fuel pressure regulator?

Customer: replied 8 months ago.
the regulator that bolts onto the back of the common rail(###) ###-####B pressure limiting Valve
Customer: replied 8 months ago.
We can talk live but know i am in Africa and dunno how good the connection will be but we can try
Customer: replied 8 months ago.
Only American Numbers ... :(
Expert:  sprinkles08 replied 8 months ago.

That's the fuel quantity solenoid.

Has high pressure pump output been measured?

Customer: replied 8 months ago.
Hi Pres Pump = 10,200 psi at Crank
Customer: replied 8 months ago.
my Phone number is +265994625407
Expert:  sprinkles08 replied 8 months ago.

How was that obtained?

Customer: replied 8 months ago.
through the Scan tool ... I have an Idaig OBDII diag tool .At Rest the pressure in rail was1900psi. and good morning.
Expert:  sprinkles08 replied 8 months ago.

Yesterday you said rail pressure was 1,400 PSI while cranking, which goes along with the hard start issue.

10,200 PSI isn't a possibility unless the engine is at full load and near the rev limiter , nor is 1900 PSI with the engine not cranking. If these are honest figures then you either have a scan tool issue or an inaccurate rail pressure sensor.

Customer: replied 8 months ago.
Can I send page snap shots of the results ...? will they paste on here ..?? These are the results I see on the screen and a brand new Scan tool ..
Customer: replied 8 months ago.
I have the Car in front of me now...Running after a push Start.
These are the Results we are getting as we Speak(with someone to help me read as i am not technical)
Engine running: 28,530 Kpa
When engine was cranking: 10,250 Kpa
When engine was not running: 650Kpa
Airflow rate 17.03 g/s
Air Intake temp 48 deg C
Engine RPM 829rpm
Customer: replied 8 months ago.
What Other results can I take down as we are on the Car ..?
Expert:  sprinkles08 replied 8 months ago.

What is rail pressure while cranking and the engine will not start?

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