common rail fuel pump help

[bembo449]

ive recently bought a deisel ghibli as a non runner and after much head scratching i think ive found the issue , there simply isnt any fuel coming out of the Bosch HP pump on the engine , its fed off the camshaft so no electrical assistance so has anyone experience of these pumps ?? is my diagnosis sound ??

 

[mersum1es]

So it is either OM611,612 or 613 engine... (W203,W210,W220)?

It depends, latest W203 does have pump in tank, other don't. So other models you can first check if aux pump is running, remove hose from aux pump to hp pump, and put friend crank the engine (spill hose to bucket). Also if I would know age of the car, I would know if there is a shut down valve in hp intake line. Check wires of valve, if it exists.

Has anyone tried to some 'repair' to engine? Hoses are easily put in wrong direction on hp pump connections.

 

[bembo449]

no pal its a MV30 deisel , 2015 , yes it looks like its been apart , i will go check the fuel connectors now

 

[mersum1es]

What is MV30???

So beeing 2015 it must be either OM642 or OM651.

So no chance mixing hoses in them. BUT they DO have electric pump in tank. Should be priming when ignition is turned on. Same applies, remove hose from filter, put ignition on and...

 

[bembo449]

you were right , they had the fuel pipes on the wrong way round and havent torque down 3 of the injectors properly but it still wont start

 

[bembo449]

What is MV30???

So beeing 2015 it must be either OM642 or OM651.

So no chance mixing hoses in them. BUT they DO have electric pump in tank. Should be priming when ignition is turned on. Same applies, remove hose from filter, put ignition on and...

maserati use a venturi motor 3.0 derv now , not an MB unit also found in the grand cherokee

 

[bembo449]

So my ghibli still isnt running , in a nut shell , there no power to the injectors, im thinking its not getting the signal to fire , just need to figure out why not , any suggestions very welcome , only code is U1424 but i dont believe this code stops the car from running

 

[V6Matty]

Search of the net on that code would indicate torque signal not received, so would sound like there is either a sensor or wiring fault to work through, I think your only option will now be a diag with live data to see if you can spot which sensor is either way out on its signals or giving nothing at all

 

[supernoodle]

Not sure how you're checking signal to injector, but both high and low side are switched by the PCM. So you won't just see a supply on one pin. Current clamp around one of the injector wires(not the pair) and oscilloscope is the best way of monitoring these.
Common rail injectors typically won't operate before 120~150 bar, so if rail pressure is below this, PCM will not energise the injectors.
Engine speed needs to be seen by PCM too, so you need to check in diag tool this is reading sensible values too.

 

[Doug1234]

Clear the code and put a good battery on it and go from there and see what happens

 

[bembo449]

Search of the net on that code would indicate torque signal not received, so would sound like there is either a sensor or wiring fault to work through, I think your only option will now be a diag with live data to see if you can spot which sensor is either way out on its signals or giving nothing at all

Well matty , funny you should say that but i think the crank sensor isn't the correct one for the car ! After much research and head scratching, my car has stop / start and apparently has a different crank sensor whos part number is different to the 2 i got with the car , only issue is it doesn't look anything different to the ones i have SO can i be a different spec ?? No one seems to know

 

[supernoodle]

U codes are for comms errors, so things that communicate over a bus, CAN, LIN etc. A crank sensor is hard wired to the PCM so it won't be cause of the U1424 code.
Stop start vehicles use bi directional crank sensors, ie they can distinguish which direction the engine is rotating. Important for stop start, just as the engine comes to a rest it is likely to reverse rotate a few degrees. Keeping track of the exact position means the PCM doesn't have to resynchronise with the cam sensor again at the next start which would take too long.
Externally the sensors usually look the same, the difference is the signal generated, the pulse width is different for a forward and reverse rotation.

 

[bembo449]

U codes are for comms errors, so things that communicate over a bus, CAN, LIN etc. A crank sensor is hard wired to the PCM so it won't be cause of the U1424 code.
Stop start vehicles use bi directional crank sensors, ie they can distinguish which direction the engine is rotating. Important for stop start, just as the engine comes to a rest it is likely to reverse rotate a few degrees. Keeping track of the exact position means the PCM doesn't have to resynchronise with the cam sensor again at the next start which would take too long.
Externally the sensors usually look the same, the difference is the signal generated, the pulse width is different for a forward and reverse rotation.

Thats precisely the info i was looking fir sir , thankyou

 

[bembo449]

So , fitted a new crank sensor , car still wont fire up , fuel pressure 300bar but no power to the injectors, there is the issue just unsure what to look at next ???
Any suggestions welcome at this point

 

[V6Matty]

Not undone any fuel lines doing other things?, possible that you might have caught a wire, I’m guessing really now but worth checking I guess

 

[bembo449]

No pal , fuel is getting to the rail no problem at all , ive scoured all over but not found anything amiss , a broken wire would surely bring up a code eh ?

 

[bembo449]

There are known issues with intank fuel pump on these engines causing a non start but as i have 300bar at the rail ive pretty much ruled that out

 

[Doug1234]

supernoodle mentioned engine speed, I have read before the om642 for instance will not fire injectors if cranking speed is below 200rpm. Does this engine operate in such a way ?

 

[bembo449]

supernoodle mentioned engine speed, I have read before the om642 for instance will not fire injectors if cranking speed is below 200rpm. Does this engine operate in such a way ?

Im not positive but i have made sure the battery voltage is supported by running jump leads off my other car , a friend who has a ghibli too , his starts literally on the first crank so it appears engine speed may not be critical!?

 

[supernoodle]

The speed itself isn't critical, but for a normal start the PCM needs to have syncronised the cam and crank signal. That means it's happy with the pattern and the phase has been detemined.
The diag tool should show you this, or at the very least you need to confirm there is an engine speed reported by the tool. That would imply this is OK.

How have you determined there is no injection request? A decent diag tool would show an injector energising time if you can't physically measure on a scope.

If you've got an energising time, does the engine use Piezo injectors? Piezo injectors have a hydraulic amplifier that if allowed to empty will result in no injection.