My 2.7L CRD Mercedes 5 cyl. cranks but won't start in the mornings. Garage says it looses it's fuel pressure over night??

Asked by Jan 14, 2016 at 02:26 PM about the 2004 Jeep Grand Cherokee Overland 4WD

Question type: Maintenance & Repair

2004 2.7L CRD fitted with Mercedes 5 cyl. engine. Cranks fine in the morning but will not start. Main dealer thinks it's loosing it's fuel pressure over night so probably has an air leak some where in the fuel system. I've changed injectors and heater plugs and some of the fuel lines. Now I'm told it could be the black plastic non return valve that fits on top of the fuel filter. Can anybody help as this is getting expensive.

1 Answer

50

This sounds very familiar. For some time now the fuel hose, on my 2003 Grand Cherokee 2.7L CRD ( Mercedes engine), from the top of the fuel filter to the low pressure pump on the front of the engine has been gathering air from somewhere…(usually overnight). Cranking the engine for 30seconds or so sometimes re-primes the system and the engine will start but prolonging the cranking also runs down the battery! The obvious difficulty is that you cannot see any diesel fuel leaks and this strongly suggests that air is leaking into the pipe leading to the low pressure pump. This is the pump and hose combination that draws (sucks) fuel through the fuel filter from the fuel tank. (There is no electric pump in or near the fuel tank.) To prove that it is an absence of fuel in the low pressure area try drawing fuel through the priming socket that sits on the top of the engine alongside the CRD rail. The low pressure pump should now prime the high pressure pump and the fuel pressure sensor should be able to initiate an engine start. If the engine fires then you have identified the problem as an absence of fuel in the hose from the fuel filter. The question now is: How do you identify where the air is getting in? A likely suspect is any one of the tiny “O” ring seals that forms part of the preformed Mercedes fuel hoses which are not cheap and very likely to break when you try to remove the hose just to examine the O rings !!! Bite the bullet and replace the entire low pressure hose assembly (including the primer port if that has been used a few times) If the problem persists or changing the hose does not cure the problem then maybe the fuel pressure sensor has failed as well.

5 of 5 people found this helpful.

Your Answer

Jeep Grand Cherokee Experts

  • #1
    inuevafreak
    Reputation
    2,170
  • #2
    Tom Demyan
    Reputation
    2,070
  • #3
    thejeepdoctor
    Reputation
    2,000
View All

Related Models For Sale

Used Dodge Durango
263 Great Deals out of 24,854 listings starting at $1,500
Used Ford Explorer
1,081 Great Deals out of 67,957 listings starting at $1,500
Used Toyota 4Runner
343 Great Deals out of 29,180 listings starting at $1,500
Used Jeep Wrangler
366 Great Deals out of 20,463 listings starting at $2,500
Used Chevrolet Tahoe
817 Great Deals out of 39,940 listings starting at $1,900
Used Ford F-150
3,017 Great Deals out of 230,435 listings starting at $1,300
Used Chevrolet Silverado 1500
2,727 Great Deals out of 156,983 listings starting at $1,000
Used BMW X5
391 Great Deals out of 16,473 listings starting at $2,800
Used Honda Accord
858 Great Deals out of 87,544 listings starting at $1,444
Used Ford Mustang
344 Great Deals out of 42,031 listings starting at $1,488

Used Cars For Sale

2018 Jeep Grand Cherokee Overland 4WD For Sale
1,762 listings starting at $39,870
2017 Jeep Grand Cherokee Overland 4WD For Sale
5 Great Deals out of 319 listings starting at $34,997
2016 Jeep Grand Cherokee Overland 4WD For Sale
6 Great Deals out of 115 listings starting at $28,995
2015 Jeep Grand Cherokee Overland 4WD For Sale
29 Great Deals out of 789 listings starting at $21,995
2014 Jeep Grand Cherokee Overland 4WD For Sale
12 Great Deals out of 562 listings starting at $15,988

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.