Morning Alan. You maybe a mondingo man but anything you turn your hands to is always worth watching as I’m sure it’ll help others with similar problem. Great video cheers Stevie.

Get the pump out of the trashcan and do the check my automotive teacher advised thirty years ago: put your mouth on the suction side of the pump: you should not be able to suck. Then put your mouth on the pressure side of the pump: you should not be able to press (blow) air. I bet one of those checks is faulty and your seal is a pretty good candidate. If the test are both correct it wasn't the pump after all but maybe the leaking connection to the pump you pointed out. Regards from NL champ!

Excellent !! My Sprinter 416CDi has this engine & fault as now its getting cold. Found your channel by accident & can't thank you enough.

When I look for diesel systems pulling in air I find it helpful to force fuel down the line from the tank as fuel seeping out is easier to see than air leaking in. Well done, I bet there was job satisfaction when you got to the bottom of that car!

Had exactly the same problem on my ml270 a few years back. Changed both pumps but to no avail, it was the fuel line o rings letting in air! Swapped them out, and bingo started first time every time.

Alan...what a great find. Good work. Thanks for your effort.👍👍

OMG!!! You're a star! My bloody 2005 ML270 has been off the road for over a month. Four visits from the RAC and a mobile mechanic couldn't figure out what was wrong with it. Like you said, no error codes. It's been recovered to my local garage (who were planning on removing the back seat to access the fuel tank), and tomorrow I'm going to show them this video. I owe you a drink!!!

Alan this is a very common problem, from memory you need to replace all the o rings on all the plastic fuel lines, about 6 in total starting from the fuel filter to the HP pump. Any long cranking starting issues is air in fuel lines caused by the seals. The new modified seals are green in colour around a £1 each from Mercedes. I’ve owned an ML270 since 2007 and replaced twice now.Also it’s an easy quick fix just be careful with the plastic clips on the fuel line fixings.

Great diagnosis Alan, thanks for sharing

A lot of people don't realise that a "single" diesel pump (both the common rail and the electronic bosch EDC style pump) where you don't have an electric lift pumps are actually two pumps in one housing. One as you say as a lift, the other to generate the pressure. Its how they are allegedly self priming.... yeah right :D A good find though :)

Great analysis, agree with your conclusion!

Allen Great video again mate such a sime thing but something you would not think about I think you are spot on once air gets in it will stop it starting you are the man cool Phil in stoke

Thanks for that I've got an E270 with the same engine and same problem should be able to fix It now hope you are well and keep up the good work see ya

I just changed the fuel filter on mine and it is doing exactly that thing. I think it must be the o ring on the filter outlet as I touched nothing else. Unless Murphie's law of crappy coincidence struck. I did wiggle the other connections though. But this video is very helpful for my knowledge of the car.

Great video. 👍 I have a 313 cdi four cylinder sprinter. No in tank fuel pump either. Was starting with ether in air intake . Now not at all , just turning over. Tried Checking for fuel by pass in the injectors but no fuel was coming out the top of any of the injectors. Will look into the seals like in this video. Worth a crack 😆

Awesome video. Very informative. Well done mate.

We have fixed this problem, but in a slightly different way. We cut the fuel line between that pump and the filter, and inserted a non-return valve. This has solved it in about 5 minutes.

That was hardly useless it was very informative 👍

Never come across one of them pumps great vid 👍

I am looking forwards to your next Live !

Your a top notch man i knew youd fix it in my day of CAV pumps the lift pump would have got the blame lol and I bet they wont sell you a seal

Yes, I think You are right Alan, great job and good catch:):)

I'd a similar problem with the same type of jeep, turned out a leaking injector, the slightest leak back ever seen caused the same problem as you encountered, that's little pump is a good heads up for any future issues I have 👍👍💯

Top job Alan , at least its sorted , I like the bonnet stay 😂😂😂😂😂🙈🙈🙈👍👍

Allen You could by pass that pump just extra crap not really needed that they bolt on some engines I would say you are correct the seal was worn out how it was not leaking fuel was a miracle love the video mate Phil in stoke

I reckon you are right. German rubber gaskets are a bit naff anyway as we have learnt from a number of BMW related oil leak repairs on You Tube.

Exactly the same problem on my 2003 ML. What about running sealant around the pump joint (outside), do you think that might work?

Well done mate

Optimal! Most likely you are right, greetings from Italy

Hi Allan, been scratching my head with a similar problem, but in my case, it starts fine in the morning and once its hot, it takes forever to start or starts and shuts in 2 seconds. No codes. Replaced seals in control valve, pressure valve is OK, fuel filter replaced because it contained some metal particles. Bizarre thing, once it starts, it turns ok, no power loss, just a lot of black smoke in high revs. Any idea? Thanks for the video.

Good bit off investigating 🔎 nice to see miss money penny in on it 👍

Hello Alan! I have a Jeep Grand Cherokee 2.7(the same engine from Mercedes’ ml) and I have I think the same problem but my Jeep start every time when is cold but he dies in 10 seconds. After cranking for 5-10 times he start and I don’t have Problem the rest of the day… what did you think I would look at? Thank you

You could get the smallest air lock in a diesel system and you will be in trouble.... especially on older vehicles

Perfect solved my issue 👌 👏

Thank you.

Is that similar to a scv valve I've very same issues but on a avensis d4d ??

Nice one 😊

TAHANKIOU ALAN

nice work

My firm had a fleet of John Deere tractors in 2005 and they had issues with diesel running back. They had a CAVDPA type injection pump and a low pressure electric lift pump. It was an official modification the put a non-return valve in the line from the tank to stop the fault.

You are Guru-mechanic👍👍👍👍😎😎😎😎😎😎

I still don't know what the other little unit is called , is there a replacement seal .

Hello, thank you for your great video, I would like to know if my problem could come from this pump, I start very well when cold and as soon as the engine heats up it is impossible to restart, my fault code is 02 51. Checking the fuel dosage of the injection pump "A" Malfunction (cam / rotor / injector)... thank you in advance I will order this part I will first try to replace this O-ring which may be a problem of air which prevents me from having the necessary pressure for starting. but it's strange that when cold it starts well.😊

fuel rail pressure sensor o rings do the same thing and the fuel by passes back down the return line causes the same long crank problem

Alan, the o ring you think is the problem is under pressure so it would leak diesel, my money is on a worn drive shaft seal sucking air ( a common problem on hydraulic oil pumps). BTW a similar starting problem on a VW, transpires is was a jammed oil pressure relief valve jacking the hydraulic lifters out losing compression.

please share the link where you got that from

My 1.6 astra cam shaft blanking plate seal went flat and hard at about 16 years old and the oil was leaking that much i though the head gasket had gone.

Hi. Wow. That is aoooo interesting. Thanks so much for the info. I'm gonna try this with my c270. Thanks for a great video. Much appreciated. How did you finally bleed thr the fuel? I'm at this point now.. Just finished rebuilding the whole motor. Thanks again

Do we know what part number it was? So i can find the oring?

Does anybody here know why the ML 270 would stall under load. It seems to be pressure differentials, but I changed the high-pressure regulator, and it didn't fix it.

The Peugeot 2.0l hdi engine is famous for the tank draw fuel pump grinding brass and putting it in the fuel filter.

I think you're bang on with the diagnosis there. Well spotted ! A poor attempt of a lift pump haha

Im having a similar problem.i took apart the thermostat.and took off one of the diesel fuel line.when finish i can't get this car too start.

You just could be a genius, thousands of Mercedes straight 6 E320 cdi have been scrapped as nobody could fix this fuel draining back issue. I spent thousands trying to fix this and had to scrap the car. I wonder if the straight 6 3.2 cdi has this same pump. If so you are a genius, nobody has ever fixed this issue to my knowledge before.

How did you bleed the system

i have got the same issue with my transit mk6 i guess i will tell mechanics to forget abou high presure fuel pump and find air leak instead. Thanks Boss

I have this exact problem. When I cold start it, it starts for a second, and then dies. Then. I have to crank it and crank it until it eventually fires. I am gonna check this out over the weekend. If this works, I will send you a present.

Thankyou 👍

I had the same issue on the jeep 2.7crdi (same engine), think had a faulty glow plug module but jeeps dont display a shit on the dash, replaced it and the plugs, now all is fine. Never in my life would i know it will not pump enough fuel when the glow plug module is toast, i saw the code but i tried like putting in hot air with the gun to check if that solves it and it did not, also it was not very cold ~10C. Very strange how ECUs are programmed to work

For me,replacing 3 injectors that were bad and putting new installing both sensors on the fuel rail solved the problem on my C270 cdi 612 engine.

Great video So theoretically Being this motor has a mechanical pump it can burn wvo

Allan Howatt can you tell me where I can buy the mercedes m 270 low pressure fuel pump cover seal please

Common issues on those OM611,612,613 CDI mercs, it's usually the green o rings on all the low pressure fuel lines from filter to hp pump letting air in. I'm more surprised at the lack of rust on an 04 ML though! 🤣

really really rate those OM612 5 bangers

I have the same problem. Try to change the rubber ring.

That O- ring did look shit, but it may have been a leaking shaft seal too. Been there done that on a Shitbox jeep with a 5 banger Merc engine and probably is the same or similar series engine as your unit. Not sure how common they are in your neck of the woods, but here in Australia they were like rocking horse shit and no parts available and what were available were outrageously expensive. And no info on them as the parts dealers say they were never brought into the country. About 400 of them snuck in. Parts were cheap and very available from the USA with about ten days delivery . The owner saw the light and flogged it off as it was un reliable.

Ahhahahahahha this story is EXACTLY what I'm experiencing. I've replaced all the fuel pipes, clips, and reconned the high pressure pump and STILL crank-crank-crank-crank-crank... (minutes later) VROOM. The only thing left is that little low pressure lift pump, and it was googling for a teardown of it that lead me here. I was also suspecting some air leak letting fuel back to the tank - if I gravity feed fuel in from a container, into the pre-heater just before the filter, then it's much easier to get started - I guess it doesn't have to "suck" so hard, and there's no way for it to leak back. But, weird thing is, I can't see any air bubbles in the clear pipes between the low pressure pump and the high pressure pump when it's cranking and cranking and eventually starting - like it isn't generating enough pressure. Those gear pumps are manufactured very high tolerances though, so it could just be a wear thing on those little gears, not enough slurp to suck in the fuel? Fingers crossed replacing mine fixes it the same way it did for you. I've been pulling my hair out over this one!

My mk4 Mondeo has an AC leak behind the dashboard, fancy fixing it for me 🙄

Bit late to the party ... but I reckon it would be a worn drive shaft housing / seal but then you would think it would pressurise the fuel and leak diesel in the engine and affect the oil level and smell and feel thin ... you could try and reseal the flat o ring with a sealant ... doubt Merc will sell you an pump o ring hence why they would rather sell you a brand new pump All fixed which is the best news ........ Mondeo next !! Just requires a clutch .... BRILL ! happy days Any auto box Taxis ? or prone to failure as I am loving my new ( 62 plate )Pug Auto van with a 2 ltr diesel lump in it same as Mondeo ?? don't miss my old Vito at all

Don’t the ML’s have a problem with the swirl flaps?

Good morning

Same engine on the Mercedes sprinter 316 CDI. 2000 to 2006.

It’s the injectors, nothing else! One of them was not working in my car and it simply didn’t start… I checked all of them and replaced the broken one… now it starts like a brand new car.

had a diesel mercedes w210, if i parked with the front of the higher than the back it would hard to start, turn out to be a leak seal on a injector

Allan, I've paused at 3 minutes to guess its a failed injector that is leaking off..... its pretty common on Mercs especially the sprinters.

4:15 - Seeing no clear pipe.

Those cogs look the same as in a Carpigiani ice cream machine pump! They only need to wear slightly and the pressure drops right off. No mr whippy! £100 for a new set. ouch.

Replace the seal??

And they like doing injectors which makes em not start pissing out of the leak offs

So whst is the problem

👍

IS IT FIXABLE?

Sorry, but why didn't you try to change just the seal? I have a 2005n ML 270 and recently I had a similar problem: very hard to start and meanwhile loosing gasoil, Was not repaired by me but in a comercial workshop, in the end they told me that was the high pressure pump loosing diesel, but they also substituted all the fuel lines, so I belive that could be a whoole of issues together. . . . more recently that bloody car was not passing the 3 000 RPM, that time was the MAF sensor. I bought it 10 years ago and I thinked by that time that I was buying a tank. When I bought it it comes with another issue in the intake manifuld, the swirl flaps where loosing oil by the axis; that was repaired by the sellerss warranty. . . well, the car it's very OK, it's easy to drive, has a great power, runs fast, in a long trip the passengers travel confortable, etc, but must be well mantained always with attention to smallest malfunction or light on; much closer to a tank is my Clio II B from the year 2000, that one, yes, resists everything. Nice video, by the way, thanks for another helpful advice.

Started with injector leak test and found out injector 3 4 and 5 are leaking.

Teach me how to clean my car air con my love 😘😘😘

It’s got two pumps on it

Sounds like a bloody tractor !!!

Its probably been in the sun too long 😃😂😃😂😃😂😃😃😂

I don't know what drugs he's on but he needs to stop them

Aussie50 covered the ML 2.7 diesel on his channel but unfortunately he committed suicide.

stop talking like that calis

You are lying 🤥, I did my benz w203 220cdi, still hard start, I change complete high pressure pump and that small pump what you talking about, but still same, hard starting, calibration test injectors is 100% working 💪, but the car hard starting and it's losing power

You too crazy 🤪, keep quiet please

Got same problem with my G. Cherokee 2.7 with the same engine, solution was changing the fuel lines that were leaking air through the orings

Great bit of deduction Sherlock 🧩 Tell you what though-didn't like the look of the big bird in the background 🦅 I think it was a Sh*te Hawk looking at the size of the poop it was dropping 🤣🤣 See you in the next one.

Hello, thank you for your great video, I would like to know if my problem could come from 17 pumps, I start very well when cold and as soon as the engine heats up, it is impossible to restart, my fault code is 02 51. Checking the fuel dosage of the injection pump "A" Malfunction (cam / rotor / injector)... thank you in advance I will order this part I will first try to replace this O-ring which may be a problem of air which prevents me from having the necessary pressure for starting. but it's strange that when cold it starts well. 😊