M275 will not start (but does turn over)

[pillow]

Hi all,

I have recently (3 days ago) bought a 2007 CL600 with the M275 biturbo V12. A couple of days ago I had an issue arise where the car would not start following a drive. After leaving it for about 10 minutes it started fine. Same issue happened again yesterday - drove for about 5 minutes just down the road. Parked up for a few minutes and when I got back into the car it would not start. About 15 minutes later it started and I made my way home.

At this point there wasn't an obvious check engine light (that stayed lit). Then comes this morning. It took several goes and about 10 minutes to get it started this morning - from cold. It did get going and I drove for about 20 minutes down the motorway to pickup a new Crankshaft Position Sensor (as I suspected this was the problem). At the parts place I was again stranded with a cranking engine. Eventually (after about 40 minutes) the car started - but this time with an illuminated orange engine light. I carried on home and parked up. Swapped out the crankshaft sensor and it started right up straight away. 2 minutes later and it's back to just cranking and not starting - so I'm guessing this isn't a CPS problem.

I have ordered an iCarsoft MB v2 reader so I can hopefully pull off the codes but want to diagnose as much as possible now before it arrives.

- I have pulled up the rear seats and can hear the pump humming on turning the key - and also while the car is cranking so I'm guess pump + relay are ok.

At this point I'm thinking it could be either an immobilizer issue (although the keyless entry/start seems to work fine). Potentially the camshaft position sensors. Coils (although the O/S coils were replaced 18 months ago) or the voltage transformer.

Despite all of this when the car starts and runs (and even when the engine light was illuminated this morning) runs and idles perfectly smoothly. No stutters, rumbles or anything. Pulls really well without any missing power or hesitation.

Any suggestions of what to check and how would be greatly appreciated. Thanks!

 

[Old spanners]

Hi all,

I have recently (3 days ago) bought a 2007 CL600 with the M275 biturbo V12. A couple of days ago I had an issue arise where the car would not start following a drive. After leaving it for about 10 minutes it started fine. Same issue happened again yesterday - drove for about 5 minutes just down the road. Parked up for a few minutes and when I got back into the car it would not start. About 15 minutes later it started and I made my way home.

At this point there wasn't an obvious check engine light (that stayed lit). Then comes this morning. It took several goes and about 10 minutes to get it started this morning - from cold. It did get going and I drove for about 20 minutes down the motorway to pickup a new Crankshaft Position Sensor (as I suspected this was the problem). At the parts place I was again stranded with a cranking engine. Eventually (after about 40 minutes) the car started - but this time with an illuminated orange engine light. I carried on home and parked up. Swapped out the crankshaft sensor and it started right up straight away. 2 minutes later and it's back to just cranking and not starting - so I'm guessing this isn't a CPS problem.

I have ordered an iCarsoft MB v2 reader so I can hopefully pull off the codes but want to diagnose as much as possible now before it arrives.

- I have pulled up the rear seats and can hear the pump humming on turning the key - and also while the car is cranking so I'm guess pump + relay are ok.

At this point I'm thinking it could be either an immobilizer issue (although the keyless entry/start seems to work fine). Potentially the camshaft position sensors. Coils (although the O/S coils were replaced 18 months ago) or the voltage transformer.

Despite all of this when the car starts and runs (and even when the engine light was illuminated this morning) runs and idles perfectly smoothly. No stutters, rumbles or anything. Pulls really well without any missing power or hesitation.

Any suggestions of what to check and how would be greatly appreciated. Thanks!

Certainly has all the classic symptoms of CPS failure.
Did you get a genuine part, and was the connector clean?
Apart from that you'll certainly need some sort of codes to point you in the right direction.

 

[alabbasi]

I think that you're in the money with your assessment. Get it scanned as the cam sensor and possibly the voltage transformer will store codes. If you need a voltage transformer. I have one on eBay for $300 right now.

FYI, forget about smoothness. It's a V12, it will be perfectly smooth even if you lose all 6 cylinders in one bank.

Thanks and good luck.

 

[pillow]

I'm hoping the scanner will arrive tomorrow and reveal all .

The Crankshaft Position Sensor was an 'OE quality' part. Hella brand which should be ok if have thought. The fact it made no difference suggests it's likely something else.

Having just come home from work I've had a go starting it and it started first go. Turned it off after 10 seconds and gave it another go and it started fine again. The engine light is still on though so I'm sure there's at least something stored. Can a duff cam sensor cause these issues without any of the other symptoms? (No cutting out, roughness etc.)

 

[Old spanners]

I'm hoping the scanner will arrive tomorrow and reveal all .

The Crankshaft Position Sensor was an 'OE quality' part. Hella brand which should be ok if have thought. The fact it made no difference suggests it's likely something else.

Having just come home from work I've had a go starting it and it started first go. Turned it off after 10 seconds and gave it another go and it started fine again. The engine light is still on though so I'm sure there's at least something stored. Can a duff cam sensor cause these issues without any of the other symptoms? (No cutting out, roughness etc.)

Apparently a cam sensor can as it is only used at start up, so you may see that when you get the codes read.
Have a look at the connector.

 

[grober]

I don't like saying it but does that vintage of M275 have these dodgy ignition cassettes?
M275 ignition coil packs, supplier in Europe?

 

[pillow]

Apparently a cam sensor can as it is only used at start up, so you may see that when you get the codes read.
Have a look at the connector.

Thanks. Before I pull off the intercoolers to tackle the cam sensors I will see what the diagnostics return. If I find cam errors then I'll check connectors and replace if necessary.

I don't like saying it but does that vintage of M275 have these dodgy ignition cassettes?
M275 ignition coil packs, supplier in Europe?

It does but the car had a new set only 18 months ago. Even if a cylinder or two were to fail surely it would still start?

 

[grober]

There is a transformer [ power supply] associated with these ignition cassettes which might be overheating?? They can go bad as result of driving [ electrically] faulty cassettes for a while. Latest part no for these is A0001500258
HERE'S A VIDEO

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[Ginger55k]

I see your in Hampshire, get the car to PCS, the m275 needs star and more importantly the knowledge to understand what its saying, ollie jack and graham know them inside out, looked after mine till i decided to down grade back to an AMG

 

[pillow]

I see your in Hampshire, get the car to PCS, the m275 needs star and more importantly the knowledge to understand what its saying, ollie jack and graham know them inside out, looked after mine till i decided to down grade back to an AMG

I may well need to if I cannot manage to sort it out myself. thanks

 

[pillow]

Ok, an update.
Got the iCarsoft reader today - seems a nifty bit of kit and not bad for the price.

Now there were a number of error codes some of which may have been historical but the most interesting were fuel injector 1-6 injector circuit malfunctions.

What is also interesting is when I was monitoring the live data values the B6/3 camshaft hall sensor, right bank of cylinders) result was "implausible". Possibly a duff cam sensor on the drivers side causing all of this?

Having said this it started absolutely fine first time when I tried it, went for a 40 minute drive (spirited in places) got home, waited a couple of minutes and she started up first time again.

 

[pillow]

So an update for anyone that stumbles upon this thread.

New batteries didn't appear to cure it and sent my abs/esp crazy. But after pulling fuses out on modules and putting them back, double checking all front ECU and front SAM connections and replacing the Terminal 87 relay, engine relay she appears to be firing up just fine now. Hopefully this isn't just some coincidence.