HCF

Hello I am the proud new owner of a 2011 GL-350 with a 100,000 miles
First assessment it seems to be in excellent condition ,Drives nice and starts well in cold climate .
I now have a" Cranks over but no start " situation
Here is what I know
the last two times I toped off with fuel the reading did not register above 3/4 tank ?
There was several times I went to start and it tuned over with no start after a recycle it started
it ran fine but I might of noticed hesitation once or twice but not enough to get nervous

I was told the fuel filter was changed when I bought it ( I am going to put an OEM one in myself for piece of mind )
I replaced the Crank shaft position sensor But that is not it
checked fuel pump fuses and I am now going to check fuel pump relay

my questions :
1_ if the in tank boost pump is faulty would that make sense with my symptoms ?
2_ is there a way to trouble shoot and then bench test ?
3_if they are known to be faulty is changing it good insurance ( I noticed a new part# does that mean upgraded unit ) ?
4_ would the high pressure pump fail suddenly our does it fail over time
5_ best diagnostic computer for the GL-350 ?


thanks Herb

Plutoe

A--do you have spark and B--do you have rail fuel pressure and C--do you have the tools to even try to determine answers to those questions!!

HCF

The GL-350 is diesel (no spark )
I ordered a special fuel test kit for this , there are two fuel pumps
1: Boost pump in the tank
2: High pressure pump on the engine ( the one I hope I don't have to change $$$$ )that feeds the fuel rail
this Machine is new to me so I am going to learn what I can before
tearing into it
I am going to invest in a good Scan tool or PC based software that speaks
MB...BMW and Land Rover so I can move into the new century .


Any advise on scan tools would be welcome
Thanks Herb

007_e350

First things first, 1 - see if you have compression 2- check if injector' s getting fuel and spraying, maybe pull one out and see what it does when you crank 3- if both are good darn timing issue could be another thing, if the timing chain stretched too much it could throw timing off.. yes sir as weird as it sounds it's happened to a few on here

alx

you need to connect your car to star/ das and have a lookie lookie into the bosch engine mgmt module

HCF

I ordered the AutoEnginuity's Scan tool software and Mercedes expansion module .
I just bought a New OTC Genisys touch ( It is useless on the GL and on my BMW
and on my rover ) Don't buy one with out trying first .
If this doesn't work I will get the star unit .
Are there any parameters in particular on the engine module I should look for ?
The engine ran perfect then one mourning Crank but no start ?

alx

it (probably) have errors you can use to pinpoint issue.

star/ das can provide a myriad of actual values that will help you (like fuel pressure at primary pump and secondary pump, glow plug condition, water content in fuel filter, etc.)

the 3/4 tank could be a faulty evaporative canister which will explain the no-start condition. this can also be troubleshot with star/ das. however, it also could be a sticking level sensor(s) and it that case it has nothing to do with your no-start condition.

HCF

alx ... witch star /das diagnostic unit do I need for my car (2011 GL-350 )
I have seen so many versions available .
Can you recommend a good source for purchase ?
and it will give me my fuel pressure values on the primary side and on the fuel Rail ?
If so then that saves me from having to measure it mechanically )
Assuming that my primary Boost ( in Tank fuel pump )is faulty can that cause a sudden no start ?
I have read in a few places that several in tank boost pump failures were proceeded
by the fuel tank sending unit acting strange.
I just want to learn more about this system (OM642 )and get the right scan tool & software and get comfortable with it before I rip it apart .

alx

it doesnt matter for your model year. a c3 or a c4 would work just fine. get a c4 if you can

no. but they are not hard to find

i dont remember and i dont have right now one of those trucks to check... sorry. would look on mine, but it is on vacation with some of the extended family... but i believe you can get actual values at least on the common rail side which is what matters.

absolutely. if your primary pump is weak or dead or filter is clogged the high pressure pump is starved for fuel which results in cavitation/ air and hard start or no start at all depending on outside temp and the phase of the moon...

i am not aware of such relationship... the floats of the sensors get stuck resulting in not being able to read "full". this is somewhat common and is usually indication of sludge... which brings me to question how clean the fuel system is and if your no start is a result of sludge and clogs. so... before you do anything please change fuel filter and take it from there.

HCF

I have a new fuel filter on its way(OEM its the one with the pre heater )the dealer I bought this car from said they put a new one in but until I do it I won't cross it of my list.
Also ordered a new fuel pump for good measure ( there has been a upgraded unit from Mercedes ) when investigating under the back seats I noticed the port side (Drivers side) access panel to the tank had been removed once .
the passengers side ( were the fuel pump is located was un touched )
I want to check my values on the pump before I pull it .
I signed on to startekinfo for some light reading ( wow again wow ) I saved as much info as possible so I can go back and start rapping my head around this .
I am investigating what the drivers side in tank unit is for, I am learning that now
( return swirl pot of some sort not sure if it is a different setup then the gas jobs )
finding the right diagram in Web ETM is half the battle .
I want to open up the tank after just to see the condition then I will install the new pump ( pumping out and cleaning if necessary )
The engine ran perfect no starving or hesitation the next mourning Crank no start
So I will be waiting for the scan tool software to get here meanwhile I will be slogging thru all the good info I pulled of startek.
thank you HCF

HCF

Update
here's what I know
first : the fuel filter is the water level style not the heater type ( just for the record )
my no start condition is because my Boost pump ( in tank primary ) is not cycling on .
I have power to terminal# 30 at Relay F4 in the boot fuse block
when I close that circuit the pump energizes allowing me to start the vehicle .
So working backwards following the relay control circuit to CAN bus C ,
I now am going to check the next culprits ( Fuel pump control Module onward )
My software should arrive today then with a little learning curve and some luck I hope to narrow it down
I am under the assumption that this pump modulates if so then does the Quantity Control Valve on the High Pressure Pump control this ?
If that is bad the whole thing will make sense because the last thing I did was change the Oil and I cleaned around the oil filter housing with brake clean ( the QCV is right there )
..... FOR THR RECORD the OTC Geneses Touch fully updated is useless on my GL-350
any insight on were to look is greatly appreciated I will up date when I have something to report
HCF

KrustyKustom

I was going to guess glow plug relay or module but you saying no juice at fuel pump is probably it. When I bleed my fuel filter (key to 2 position, start button removed), it bleeds fuel like 3 gallons a minute!

I use a Star C4 (4 Benz products in the house), and it is beyond awesome. The stuff you can do and troubleshoot is awesome, so much I will keep driving Benzs so I can easily work on them.

HCF

I am going to try Auto Enginuity the pc based scan tool with the Mercedes
expansion module . I know the BMW and Land Rover guys like it .
Hopefully it will arrive today and I can chase down my issue on the fuel pump. I will give it a try But I am sure I will eventually end up with
the star unit .


Question
1: when the low pressure fuel system functions normally what device modulates the Boost Pump ( in tank pump ) ?
2: I believe one of the devises is the Quantity Control Valve on the high pressure pump ?
3: also the fuel Temp sensor and the Restraint system send info to the CDI witch controls the fuel pump Control Unit ?

Has anybody changed out there Fuel Pump control Unit ?


It will be nice when I get the scan tool so I can stop guessing , Hopefully I can decipher the Info
HCF

alx

why are trying to reinvent the sliced bread? get a star/ das with wis and call it a day. you seem to be technical enough so your learning curve will be short and sweet. we can help with the unknowns.

a star/ das will allow you to look into all the modules, read actual values and actuate functions and when they fail - offer you a decision- based tree troubleshooting with diagrams.

gl450x164

Exactly you'll end up spending more than what can be had for a c3 c4 system

HCF

I agree (I am afraid after drinking the cool aid I thought I could get a platform that would work for My MB BMW and my Rovers )
wishful thinking !


Any way after replacing my fuel pump ...It works
fuel gage now reads correctly Pump cycles on with out relay jumped out .


..............I can only assume the old pump was drawing more power then it should . ( so it would only run with the relay jumped out , doesn't make sense )

I don't know for Shure if everything is right but with out star I am guessing
also I can't find my fuel pump control mod. it is not were the info I have says it is ?
this is a 2011 gl-350
Putting the seats back and carpet then I will take it for a ride . I have cycled it on and off half a dozen times and all is well (so Far )
I hope it was just a defective fuel pump and not some mysterious
computer thing .
will update...HCF