http://www.jeepforum.com/forum/f310/cooler-diesel-line-why-1324431/

 

Spot on...and as MTM linked you to...its a diesel cooler...the returned fuel get a tad warm after being compressed up to a possible 21,000PSI! So whats the problem with yours....there not much I have not had apart on my fuel sysem for one reason or another!!!:thumbsup:

 

thanks for reply.
Jeep wouldnt start on Tuesday. No previous problem. Thought i might have been a wee bit hasty and not given coils enough time but just turn over no sign of life. i was low on fuel but not empty as far as I knew.
So I thought stick in another couple of gallons but no good. Not getting any smoke out of exhaust white or black. So time to get hands dirty. Loosened the bleed screw on the top of the filter & cranked - no diesel. removed the drain plug from the filter, cranked No diesel or even water. Put them both back and loosened the feed pipe from the tank and cranked ---- no diesel. I guess i have sucked up dirt OR pump has stopped working. Then started to search net for info and cannot get a handle on where the pump is on this motor SOOO any input appreciated especially if backed by experience of the 2.7CRD.

 

First, if you loosen that "bleed" screw on the filter when the engine is not running all it will do is let air in the low pressure lines and let the fuel run back towards the tank. Second, our fuel system is NOT self bleeding....in fact if you have cranked it over for more than a couple of minutes without fuel in it the low pressure fuel pump may already be damaged and the metal particles from the low pressure pump may go on to damage the more expensive high pressure ..... I found this out the hard way! Thirdly the actual bleed valve is on top of the engine under the pull off plastic cover. I use a large oil serInge (I use the same one I use to top up my dIfs) to suck the diesel through it until it comes through air free. I also squirt a bit of easy start into the intake while I crank her over to allow it to start whilst the fuel rail is still pressurIsing for a quicker cleaner start. From then on it should start fine unless you have a fault.... the most common of which is cracked o rings on the low pressure lines that allow air into the system and the fuel to run back..... if too bad and letting too much air in, it will never start. Buy the green Mercedes ones, not the crap black Jeep ones...same price..better shape and material. Be prepared to buy one or more of the low pressure lines (£15-£25 each) when you accidentally break a few of their connectors when trying to fit your new seals due to the heat making them brittle! Good luck.

Pump locations.
Low pressure. Top front of engine to left of vacuum pump.
High pressure. Below low pressure pump...cast metal three lobed shape.
And yes that poor little low pressure pump has to suck thick cold diesel all the from the tank and through the filter on a cold morning....amazing they start at all!

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Alfaitalia,
Thanks for that info. It makes sense now. What I was seeing on the web was not what i was seeing on my Jeep. A great Merc engine when its running but difficult to get info on when trying to get parts or repair, and our local Jeep dealership is less than helpful.
With the info you have given me. I guess no prizes for guessing what I'll be doing this weekend.
Thanks again I'll keep you posted.

JMC

 

Who's you local dealership there John?

I use Belmont down near the Gyle and a guy called Russell who is 100% spot on! I get a little (being the operative word) discount from him but at least he tries to help. Grieves (Falkirk) are pants as are Murray in Shields Road, Glasgow. So its very difficult to obtain dealer parts in the central belt, so much so that I order from down south as they tend to want to "play" more ..

Just me $2 worth...

 

The excellent Mercedes dealer near me can now only help with engine parts since FIat took over. The nearest FIat dealer is crap and wont be getting my business! Online parts for me. Just got my 5lt of 247 fluid online..... half the price FIat quoted ......even with postage?

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It was an Edinburgh Jeep dealer( Who shall remain nameless) who could not show the engine on a micro fiche , just a list of parts ( it was a small clip that retained two fuel lines to the lhs of the engine block ) the partsmen did their best but the info just wasnt available within the dealership. I took pot luck & ordered a piece in hope. Incedentely emails to Fiat customer service took weeks to get a reply and then referred me back to dealer. the part turned up from Italy ?? about three months after I had fixed it.
I went to Merc and they told me they couldnt look it up without my Merc reg. Jeep no use. So I went on Gumtree and got the reg off an ML series of approx same year back to merc hey presto nice helpful lady in parts dept looked it up then got the part off the shelf and Bobs you Auntie Job done. it just shows there is a bit of luck.
Any way we digress for this Friday moan.
I,m off out into the artic weather to try and progress the present problem.

 

Got Snow Have you Lols! Can we come and play too ;-)

 

Can anyone advise how to remove the feed pipe from the centre of the filter which goes to the lift pump.
it has a black plastic fitting about the size of a ten pence onto which the clear plastic pipe fits at right angles
It appears to rotate and has two lugs on it which suggests to me its a push fit & pull lugs to remove but I dont fancy breaking it. The picture of the new filter does not show this item

We dont have snow but it was Baltic this afo.

 

There should be a white forked piece of plastic that goes between the lugs (if not removed or snapped off the last time the filter was done). Push that and it will force the lugs apart so you can lift the pipe out.....well thats the theory.... in reality the white piece will be missIng or won't move the lugs enough to remove the pipe so you will use two small screw drivers to lever the lugs out and just as you think you have got there one of the lugs will snap off (due to hardening from the heat)...but at least then you can remove the pipe and change the filter. After driving around for 6 months with a cable tie holding the connector on the filter (which is fine due to the low pressure and the new o ring you should have fitted!) you will get around to buying the new diesel pipe to fix it as the connectors are not available separately.......well thats what happened to me anyway!

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EXACTLY,
All as you predicted right down to the cable tie by someone previous and with the additional difficulty of the electrical sensor on the bottom leaked like a sieve when i put it back. I find after some more research that this should be twisted after being inserted. being niave I thought that was what the cable tie was for. Anyway its all good , not so clean fun. Its about thirty years since I had to work on cars so I,m getting there slowly. Your advice has been invaluable. Going out to Halfords to buy a vacuum pump today and Mercedes tomorrow to buy the LP fuel line from the filter . Still got fingers crossed re whether I have damaged the pumps but just need to cross that one when I get there.. Do you see any down side to priming the system from a jam jar to prove the front end just in case its a blockage at the tank end. Since I,m going to merc what o rings would you change if it was you motor.

 

Don't quite see how you could use a jar to feed it unless you connect to the intake side of the filter.....if you did I would need to be a very big jar as the fuel system pumps excess fuel back to the tank at quite a rate so a jam jar would be empty in about two seconds!

All the low pressure ones (only about 90p each) and you need about 5 or 6 of them.... can't remember and since its 1am and I can't sleep in not going out to look!

Also the one on the high pressure rail return valve on the back end off the fuel rail which is bigger than the rest but can cause problems when it leaks.

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I swapped out my diesel filter yesterday, pretty simple job but priming the lines wasn't as simple as i thought. Ended up filling the diesel filter and loosening a bolt above the first injector (as you would if you ran out of fuel) and primed by cranking it until fuel came out. Then tightened that, refilled the filter with diesel and repeated until it started.

Took a good hour and had to get the jumper cables on, but cranking isn't going to do much damage as long as you do it bursts of less than 10 seconds.

 

I swapped out my diesel filter yesterday, pretty simple job but priming the lines wasn't as simple as i thought. Ended up filling the diesel filter and loosening a bolt above the first injector (as you would if you ran out of fuel) and primed by cranking it until fuel came out. Then tightened that, refilled the filter with diesel and repeated until it started.

Took a good hour and had to get the jumper cables on, but cranking isn't going to do much damage as long as you do it bursts of less than 10 seconds.

Why not just use the actual bleed valve on top of the engine....takes seconds to do that way?
Assuming you have a crd and not a 3.1 of course (can't see on phone!) loosening one of the supply line bolts will not bleed it through if you run out of fuel like the old TD models....also if it did fire up with the bolt loose (it wont) the fuel , at about 21,000 psI, could sever a finger or lose you an eye!
A Bosch engineer told me that it only takes about a minute of dry running the pumps do the damage. The diesel is if only lube they have and the high pressure pump is a precision bit of kit. I learnt the hard way.....cranked her over on and off for about five minutes until she started.....about a month later she started cutting out under load. Metal from my low pressure pump was in my high pressure pump. Two recon pumps and about £300 later I was fixed....won't do that again! Just glad it did not take out my injectors too...lots of money.

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You guys are having all the fun by the sounds of it.Been snowing on and off all day here.
When I changed the fuel filter I just filled the filter with diesel when reassembling and it started almost immediately, maybe I just got lucky.
I have been spending more time on the ZJ as it needed more work but the CRD is ticking along nicely.

 

What a hero, I've had to prime my fuel lines about 6 times in the last couple of months for one reason or another. This would have saved me some time.

 

2.7CRD Fuel filter problems UPDATE.
Thanks to all especially , Alfaitalia for info. --- Filter changed. Primed and bled. Now started run and tested, all thanks to you guys. ------ One remaining problem. Will not start without a little scooosh of easystart in the air inlet. Once started ticks over and runs fine. has started on key a few times but most times still needs easystart. Pre this problem the Jeep always started first time No Prob. As well as the fuel filter I did change the feed line from filter to LP pump. Could it still be air in the HP Common Rail ?? or ANY IDEAS?????

 

I will call one of our mechanics later on and ask him for his idea. We have a few Sprinters with the same engine and he has worked on my CRD. I will let you know what he says. I have a good indy Jeep specialist based close to Kinross ( Crook of Devon) if you ever need one. He replaced the injector seals on my CRD. Very good guy.

 

Hi Mike 2909,

I would be interested in contact details for your Jeep specialist. Crook of Devon is not too far for me to travel for someone who knows these vehicles.
I reckon if I cant crack it in another week then I'm giving up and letting someone who knows what they are doing have a go.

 

Hi Have sent you a PM with his details.

 

I spoke to the mechanic about the starting problem and he says everything points towards an injector sticking open.
Using the easy start forces it to start and once running it will be ok.

 

I found this article while looking for more info. Might be of interest to you, http://www.dieselpowermag.com/tech/1211dp_why_diesel_fuel_injectors_fail/viewall.html

 

david.24@sky.com