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


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.

3 out of 3 people think this is helpful.

Your Answer

Add photo

Related Questions

Search Jeep Grand Cherokee Questions

Jeep Grand Cherokee Experts

#1 inuevafreak
Reputation 1,780
#2 Tom Demyan
Tom Demyan
Reputation 1,610
#3 thejeepdoctor
Reputation 1,470
View All

Related Models For Sale

Used Jeep Wrangler"
432 Great Deals out of 16,278 listings starting at $3,600
Used Ford Explorer"
1,312 Great Deals out of 71,769 listings starting at $300
Used Toyota 4Runner"
347 Great Deals out of 18,739 listings starting at $2,400
Used Dodge Durango"
393 Great Deals out of 22,705 listings starting at $1,000
Used Chevrolet Tahoe"
1,106 Great Deals out of 36,353 listings starting at $1,700
Used Ford F-150"
3,161 Great Deals out of 216,438 listings starting at $1,000
Used Chevrolet Silverado 1500"
2,427 Great Deals out of 143,996 listings starting at $1,995
Used Jeep Liberty"
368 Great Deals out of 9,251 listings starting at $998
Used BMW X5"
550 Great Deals out of 15,503 listings starting at $1,995
Used Ford Mustang"
721 Great Deals out of 41,404 listings starting at $900

Used Cars For Sale

2017 Jeep Grand Cherokee Overland 4WD For Sale
2,665 listings starting at $40,278
2016 Jeep Grand Cherokee Overland 4WD For Sale
4 Great Deals out of 1,074 listings starting at $38,551
2015 Jeep Grand Cherokee Overland 4WD For Sale
20 Great Deals out of 415 listings starting at $29,498
2014 Jeep Grand Cherokee Overland 4WD For Sale
29 Great Deals out of 645 listings starting at $23,986
2013 Jeep Grand Cherokee Overland 4WD For Sale
12 Great Deals out of 247 listings starting at $19,981