ML270 won’t start(low pressure in the rail)

[limp]

Hello everyone, I’m new here and this is my first post here, not sure I’m posting in the right thread but I really need your help with my 2001 ML270 CDI. The back story is that the car started having difficulties starting I had to hold the keys for a while for it to start, eventually one day it just cut off on me I had to give it a sniff of petrol to get it home I decided to get new injectors new o-rings new filter (mann) but still can’t get it to start, checked live data with my fake cheap Chinese scan tool the rail pressure is at 2-4 bars when not cranking, when cranking the highest i have gotten is 102-106 bars while hold the key for like 30sec the only why I can get it to fire is when I take of one of the low pressure fuel pipes(clear plastic pipe) or I use some easy start. One more thing I have notice of late is that when I crank the engine it cranks at normal speed for a few seconds then it drops the speed could this the starter motor going bad?

What has been changed so far
Brand new injectors
New HP pump
New O-rings
New filter
New battery

Hope I have explained and written well enough for English is not my first language.

Regards to you all
Simon

 

[limp]

Any help gentlemen

 

[Taffy7hfa]

Hi, the fuel system on these can be very troublsome to bleed. Double check that you have not mixed up the plastic low pressure fuel lines on the bottom of the HP pump.
They are also prone to drawing in air, are the any bubbles visible in the fuel lines ?.
It may be worth investing in a better code reader.

 

[limp]

Hi, the fuel system on these can be very troublsome to bleed. Double check that you have not mixed up the plastic low pressure fuel lines on the bottom of the HP pump.
They are also prone to drawing in air, are the any bubbles visible in the fuel lines ?.
It may be worth investing in a better code reader.

Thank you for your reply. I have no air bubbles in the pipes. My thought is that maybe the fuel pressure valve has given out and my cheap Chinese code reader is not picking it up. And one more thing when I manage to get it running if I in clip the connector from the camshaft sensor the car keeps running is this how it should be?

 

[Taffy7hfa]

I believe it will run with the cam sensor unplugged, is the battery fully charged ?
Probably save a lot of time and aggravation at this point to get it plugged in to some proper diagnostic equipment..Star or suchlike.

 

[limp]

I believe it will run with the cam sensor unplugged, is the battery fully charged ?
Probably save a lot of time and aggravation at this point to get it plugged in to some proper diagnostic equipment..Star or suchlike.

The battery is very change and it’s only a month old

 

[limp]

I’ll t try to find a proper code reader I guess though it’s a pain finding one here

 

[ajlsl600]

Does that motor have a tea bag filter on the pick up pipe in tank.? Has it ever been cleaned, changed

 

[limp]

Yes it does, I actually just changed the all sender unit like a month ago everything was cleaned

 

[star]

This has cost you in guessing, make sure you have pipes the right way round on the high pressure pump.

 

[limp]

I have looked at the pipes and there certainly the right way. Will look at finding a good code reader any recommendations?

 

[limp]

I

This has cost you in guessing, make sure you have pipes the right way round on the high pressure pump.

I changed the sender unit because the gauge was not working.

 

[supernoodle]

These have a mechanical low pressure pump on the engine. They have to suck fuel up from the tank. Any little leak can give issues

Check this out as a good example

 

[limp]

These have a mechanical low pressure pump on the engine. They have to suck fuel up from the tank. Any little leak can give issues

Check this out as a good example

Thanks I’ll look at that.

 

[limp]

Just a small update. Today I decided to take of the fuel pressure regulator valve I found it was corroded and the white plastic O-ring was broken and it was definitely changed by the previous owner, I’ll be getting a new one soon and I’ll be taking off the rail to give it a good clean.

 

[star]

I have looked at the pipes and there certainly the right way. Will look at finding a good code reader any recommendations?

Ok, it is easy to get them wrong, I know from experience. These two get mixed up. We only use star diagnostics.

 

[Mark A]

Thanks I’ll look at that.

We had a leak half way along passengers side and this was allowing air in with our old W163. A short section spliced in sorted it.

 

[limp]

Ok, it is easy to get them wrong, I know from experience. These two get mixed up. We only use star diagnostics. View attachment 78272

Mine has a shut off valve the pipe from the LP goes through the valve then into the HP. So it’s quite had to confuse them.

 

[limp]

We had a leak half way along passengers side and this was allowing air in with our old W163. A short section spliced in sorted it.

I want to take off the starter motor soon so I’ll take time to look at the pipes too. Thanks

 

[limp]

That’s the valve I took off