2.7 CRD fuel leak at high pressure pump

[OffroadSpike]

Hello.

A week ago i had to travel to 600km away and noticed the fuel gauge consumption didn't match the overhead console avg. consumption, I was actually spending more fuel than the 7.3l/100km the overhead console indicated. In total I spent a whole fuel tank to travel these 600km which didn't sound right. I also noticed when paying tolls or stopping at a gas station, I smelled like raw diesel around the car.

Yesterday had to take the car again and noticed a pool under the car, also it was hard to start, like a 8 second crank while it used to start immediately.

There's drops of diesel dropping from behind the high pressure fuel pump, but the leak seems to be comming from the front of it, either the fuel hose connection or a seal inside the pump.

G. Cherokee 2.7 CRD high pressure fuel pump leak - YouTube

I changed the fuel hoses a year ago, so it would surprise me it's leaking through the hose orings again.

The car has been showing the water in fuel light intermittently for some months, it only used to happen on rainy days or when I washed the car,so I gave it no importance. Maybe once every 2 weeks and disappeared once I restarted the car. Last 2 weeks it has been showing at a higher rate than before, but again, gave it no importance cause it's an intermitent problem. I don't know if this might be related or not.

First question I've got, is it safe to drive my car back to home 600km away? Although I know diesel is hard to ignite, I fear it catching fire on the way back.

Second, in case of a fuel pump seal leak, can this be a DIY fix? I really don't have any more money to dump on this car, it's an endless money pit.

[Adrian D]

Your fuel consumption will never match the overhead console exactly. 600km out of a tank is fine depending on usage, tires, lift and accessories.

You could try to re-seal the pump yourself (if the pump is leaking) but I would not advise it. I tried it twice, both times ended in failure, the pump was no longer able to reach 1000bar.

[OffroadSpike]

My Jeep is stock suspension and tires are Cooper Discoverer stock size four seasons. I would expect a lower consumption than a full tank for 600km.

How does the car calculate the fuel consumption? Is it an estimation using common rail sensors?

What if I can't reseal it? Are spare parts reliable? Should I bring it to a Bosch service center to get it fixed?

[Adrian D]

Ah, I see you're in Spain. Just take it to a Bosch center if you are 100% sure it's the high-pressure pump. It should not be that expensive.

Fuel consumption is based on calculated injection quantity I assume. The more time you spend at stable RPM, the closer the calculated fuel consumption will be to the real fuel consumption.

For reference, I drove my old WJ completely stock and the best I got was 8.1L/100km, all highway. After installing a lip to reduce air going under the car, I got 6.95L/100km once, going between Austria and Germany, no traffic, no wind, very steady speed. It would usually be 7-something.

Once you get off the highway and on national roads where you speed up and slow down due to traffic and speed limits, forget about going under 9L/100km without any aero mods.

Add some city driving or some warm-up time and 600km / tank is just fine. Also depends on how much you are willing to let the fuel level drop and risk running out of fuel in a round-about

[OffroadSpike]

So I were going to return back gome today and do the 600km back. But the car refused to start, I cranked for a long time but didn't want to drain my battery.

The situation right now is that I'm stranded with a non working car parked on the street. Took a video of the leak and now it seems to be leaking a LOT more than saturdary which is the last day I used it.

https://www.youtube.com/shorts/4AlLCyk4gXI

Took the pump out (I always carry some tools in the trunk) and now I'm debating what to do with it. Should I buy a remaned one? Should I buy one from the scrapyard? Should I take it to a Bosch center to get it fixed (I asked to a bunch of Bosch certified workshops and they don't have a fuel pump testing machine)?

What would you do?

I found some fuel pumps with same 748 numbers on the front, but different than CN 4. Is this CN number even relevant? I know this pump is shared with lots of other merc engines and I would like to know if they all work the same or they differ.



I changed all fuel hoses a year ago, but upon removal of the fuel pump,the one that sits closer to the block, has the outer white rubber deformed, not cracked but squished between the hose and the pump. The inner orings look fine. Could that leak be caused by a hose? I doubt it but you never know...

[JeanLuke]

The number that matters is the one just under the word "Bosch"

I would get a reconditioned one, that has been bench tested by the shop. I've tried doing my own, but with limited success.

Sent from my motorola edge 20 fusion using Tapatalk

[JoergM]

Since we are looking at fuel lines here. I want to change my fuel filter from stock to one with a primer pump since the CRD does not really have one, I think it is one for a Toyota Hilux. I got this tip from a CRD driver back in Melbourne. Had this filter for ages on my bench but did not think to install it ever, until now since i am working in that area anyway.

Now the outlets of the new filter are a bit different compared to the stock. for the fuel in I am not worried since it is a regular rubber fuel hose which I can replace if I have to, but for the outlet it is pointing downwards and I wonder if I can replace the clear fuel lines with a good OEM part which is more flexible. The stock ones seem to be really stiff. Not sure if this supposed to be like this or if it is just age and the diesel fuel cause them to become inflexible.