Ml270 won't start

[catrin2468]

Hi hope this in right area
Have a 52 plate ml270 Had recon turbo fitted 2weeks ago (had to have 200bhp turbo) found out she is also chipped and had dpf removed
All running well until yesterday driving along kicked down hard and truck shut down no warning lights just died pulled to side of road turned off engine which had stopped running restarted and running fine Today went out started up drove about 10miles all ok came back home parked up Just went to go back out Truck wont start turns over strong but will not fire Any ideas please as cant move her to get to garage Thank you

 

[Smart320]

Sorry to hear of your roadside breakdown. Unfortunately am not an expert but if you cannot get it to reset the electronics by leaving it for a time without the ignition switched on, I suspect you will need to recover it to a dealer or MB Indi and get it on Star to see what faults show. Hopefully someone else with more technical expertise will soon post

 

[catrin2468]

Hi Thank you for reply Truck has been recovered to local garage (who does all the work on her ) Been on machine no codes showing !!! fun times lol will keep updated as to what they find

 

[brucemillar]

Normally I would suspect the Crankshaft Position Sensor (CPS) but that should throw a code? What code reader are they using?

 

[catrin2468]

Not sure will ask at garage today The only thing that came up on reader at garage was rotate sensor failed when they had quick look yesterday

 

[brucemillar]

Not sure will ask at garage today The only thing that came up on reader at garage was rotate sensor failed when they had quick look yesterday

Hmmmm. Not sure what a "rotate sensor" is? But is sounds like like a CPS. If they go bad (and they do) they will stop the engine from starting and cut it while running as the brain cannot see where the engine is at in its fuel cycle etc. So, it acts like it has run out of fuel.

 

[catrin2468]

Hi garage said it a star reader (think that what he called it ) It is showing no codes but is registering rpm Thank you for your help !!

 

[Joderest]

Sorry, but at begining of thread you stated DPF removed. I thought, but stand to be corrected, no ML270 had a DPF fitted.

 

[catrin2468]

Sorry, but at begining of thread you stated DPF removed. I thought, but stand to be corrected, no ML270 had a DPF fitted.

Sorry got it wrong meant the cat has been removed (dpf is on daughter's car and she having probs with that ) Sorry

 

[Joderest]

That would explain that then, phew, chose ML270 because it had no DPF.

 

[catrin2468]

Lol sorry

 

[91dm]

How long was it left after doing the 10miles? Has it ever been hard started before?
Is there diesel at the injectors?

 

[Gbrowncls55]

All the symptoms say CPS. Every Mercedes I have had has had a failed CPS at some point.

 

[Tuercas viejas]

You don't necessarily need what you folks like to call STAR!
Any decent scanner will read what is going on.
The system is made and conceived by Bosch. MB use it like most manufacturers do with tweaks to suit their applications.
Ostensibly the crank sensor excites the ECM (PCM) to come to life. If an input signal from the crank sensor (which is square waved) cannot be seen it simply won't start--the whole system acts as if dead. Should the signal failure take place when under higher engine speed it will sometimes flag a CPS code. If the engine stall is a CPS failure at say a stop lamp intersection , often there will be NO CODE stored to give you a clue as to "wot happend mate!".
The clue is to use the scanner oscilloscope feature or a separate unit to "read " the waveform and its integers .
In any case working in consort to the CPS is the cam position sensor. When everything is working as it should the scanner on a MB dedicated program will show "synchronized"once the vehicle has fired and is up 'n running.

The precursor to this all is a sudden random hiccough by the engine (often goes unnoticed) before the thing falls on its face at the roadside! Then its tow truck time called "Grua" in Spanish!--I like that word! It sounds like saying "buggah" wots gone wrong now!!

For a trained tech this fundamental basic stuff, understanding & fixing no code faults. My apprentice VM students have to study this stuff at length in Tech schools.

This can be head scratcher at times. My brother who has a shop in Gloucestershire shared with me a situation where on an Audi A4 (Bosch system) the thing would start and run for a few seconds then hiccup and die.
Wouldn't start until the input fault had decayed. The fault once we shared a waveform and compared it to my US sourced waveform library, the read out from the crank sensor showed that the signal was clipped.
An aftermarket sensor installed (Made in China) the culprit ! A genuine Bosch part fitted and it ran as it should!

As a footnote you may notice I wrote hiccough in two ways!
As a piece of useless information I write it normally as hiccough being a "bit trad" and remembering a formal strict English "edumacation"! Hiccup being more American or Transatlantic.
In today's times most of the languages and their spellings are twisted or changed as per usage and sometimes as per it sounds, which is why we have the confusion of hiccup and hiccough... However modern spelling first recorded 1788; An Old English word for it was ælfsogoða, so called because hiccups were thought to be caused by elves hiccough 1620s, variant of hiccup by mistaken association with cough.
Some might think there are evil elves at work in your dead MB but they are only to be found in Father Christmas' (Santa's) sleigh.
Cheers Tuercas viejas