R129 280 Hesitation and cutout

[CraigRoyK]

Hi all,

Mt recently acquired R129 SL 280 has cut out on me 3 times (in the c. 300 miles I've done) and has a hesitation on pulling away. Of the 3 cut outs, one was while pulling away,the others were just after starting.

This appears more pronounced when cold, as I didn't notice it on the long trip home.

Based on trawling these forums, this appears that it could be the crank position sensor.

How would I go about verifying this? The car currently has 101,000 miles on it, and I have invoices with the service history which shows the CPS was renewed at 73,000 miles.

Is it common for this part to fail at such notice? As the first lasted almost 3 times as long, I am concerned that this is another problem.

Thanks in advance for any advice.

Thanks,
Craig

 

[CraigRoyK]

Hi again,

I was hoping for some input or confirmation of my theory?

I know some will say "search the forum". I have, as mentioned, I would however like confirmation before I go off and spent realtime & money on the wrong thing.

So to repeat:
Does the above sound like the CPS?
How do I confirm this?
Is it reasonable that is fails after circa 28,000 miles?
Who nearby (in Surrey) might I get to do this work? Or is it a relatively easy DIY job? (I am experienced at mechanical repairs, but on older vehicles, I.e. Pre fault codes, etc)

Thanks
Craig

 

[grober]

The intermittent crank position sensor problem usually first appears when the engine is hot. Heat transfer from the engine causes a internal electrical connection break . This is often reversed in the initial stages of the fault by allowing the unit/engine to cool when function is restored. Eventually the unit fails completely and the engine is dead till its replaced. I have to say your problem doesn't seem to fit the normal symptoms- doesn't rule it out entirely but makes less likely.

 

[CraigRoyK]

The intermittent crank position sensor problem usually first appears when the engine is hot. Heat transfer from the engine causes a internal electrical connection break . This is often reversed in the initial stages of the fault by allowing the unit/engine to cool when function is restored. Eventually the unit fails completely and the engine is dead till its replaced. I have to say your problem doesn't seem to fit the normal symptoms- doesn't rule it out entirely but makes less likely.

Thanks,

I'll keep monitoring to see if I can clarify the details. I guess I should get it in to someone who can check for fault codes.

 

[CraigRoyK]

I've got it booked in with Ollie @ PCS.

I'm looking forward to resolving this issue as it's spoiling the fun.

I'll post back here when we've figured it out in case someone else experiences the same thing.

 

[BTB 500]

Good luck, I'm sure Ollie will get to the bottom of it

 

[CraigRoyK]

All,

Sorry about the delay, but I can confirm that Ollie sorted the problem as expected. It was the air mass sensor. He also took to time to go over the vehicle as requested and point out what else needs doing.

In terms of the repair, the car now goes so much better, I was happy it before, now I really love it. I'm not an out and out performance guy (I wouldn't have bought a 280 if I was), but it great now.

Cheers,
Craig