2.7 CRD - Starting problem
 

My 2004 2.7 CRD has developed a strange starting problem...

Yesterday morning, it kicked over as usual (about half a second of cranking then fire-in-the-hole) but it only ran for less than a second and stopped. Tried to restart - no dice. Pulled out my phone, started monitoring fuel rail pressure and tried again. As I cranked, I could see the pressure climbing, so I kept cranking for about 5-10 seconds and it started.

Drove to work - normal. Parked for about 8 hours - normal restart. Went out last night for about 3 hours - started normally both at home and the venue. Went to drive to work this morning - same problem as yesterday.

Does anybody else have a teenage Jeep - doesn't do mornings?

I'm figuring it has a slow air leak somewhere between the LP pump and the tank. Thinking it through, how do you actually find it, or is it a matter of throwing random o-rings at it until it stops? What are the most likely suspects?

There are so many places:

• Fuel filter bleed screw
• Water in fuel sensor
• Fuel filter drain valve
• Fuel filter outled
• LP pump inlet
• Vacuum priming valve
• Cold fuel valve on top of the filter

I've always thought the cold fuel valve looks dodgy. Are the part numbers below correct?
Jeep 05080460AA
MB A611 078 02 49

Forgot to mention... No error codes.

I've just ordered the fuel return valve (the one on top of the filter) from moparpartsoverstock.com (via ShipItTo since they only do US shipping).

Just out of interest, what did that cost in Aussie $ and how ling til you get it?

$67, but since the earlier post they've said that they cannot supply the drain valve I also ordered, so I've requested them to can the order. I can get the valve itself from Lithuania via eBay Australia for around $40.

The old girl started perfectly today after more than 10 hours in the work carpark. Once home, I have moved and jiggled all the connections on the LP fuel system, tightened the bleed and drains, and checked the water sensor. I also slid the filter as high as it would go in the bracket (it was as low as possible before). My thinking is that the engine ran for less than a second when the problem showed up means that the air is probably right at the LP pump (anywhere else and the fuel in the pipe would feed it for longer). By putting the filter higher than the pump, I'm hoping that the air might be further up the pipe and give the system a chance to flush itself.

It's a long shot. Meantime, I've always got my priming pump under the back seat. Maybe time to buy a can of ether spray.

I've seen bad rubber fuel lines create weird problems such as fuel leaking back to the tank. The odd thing is they didn't leak fuel, they would only leak air.

I've been meaning to replace my rubber fuel hoses but have quite had enough inclination to do this job as yet.

If in doubt, it can't hurt.

Jason

What size hose is it? 8mm?

Also, most of the rubber is under vacuum, so it would never leak fuel, right?

starting
 

A common fault is the o rings in the plastic fuel line connectors. They stop sealing and allow air in and the fuel drains out of the filter back to the tank when parked overnight. When its running, check for bubbles in the clear plastic fuel line from the filter to the LP pump. You pull back the black shroud to expose the tube. If there's bubbles, there's a leak and fuel will drain back as explained before.
In the "Everything 2.7" thread, It gives part nos for o rings and complete fuel lines. It lists Mercedes Benz o rings as A6019970645. I found these were too large (15mm OD) for my 2004 WG. I need 10mm OD. I found another MB o ring part no. A6019970345 I intend to swap them and try the second part no.