Engine 850: B5254S/2.4/20v: Intermittent cut-out

[benali]

C70 2.4t auto 110k.
Occasionally cuts with engine slowing as you approach a junction; but then always starts back up no problem. (maybe once a week)
Anyway, wouldn’t start back up this morning, well not until 10mins later when I went back to it for another try.
What would be the first most likely things that may be the cause?
Give me a clue please?

[volvo again]

With faults like this it is always difficult to find the problem, is the eml on? are there any fault codes stored?
Could be fuel or ignition related, maybe idle control valve, there are a host of sensors that may be causing the engine to stop, the fact that it starts straight away seem to imply there is no major problem
Sorry if this is a bit vague...

[Volvofreak2]

Hej,

got the same Problem with my 850. So far couldn´t find out what it is, because it rests on my liftingplatform for already 2 month now!
But the first, what I would try, is, to change the fuelfilter and messure the fuelpressure in the rail.

Hej Gernot

[Simon J]

I had a very similar problem with my C70 auto although it didn’t actually cut out - it just seemed that some relays dropped out and the radio would momentarily cut and there’d be a dreadful 'clunk' in the transmission. My local auto sparks traced it to a bad connection on the main battery charging cable. They replaced both it and the main earth cable connection some months ago and so far (touch wood) everything has been fine. Worth checking out.

P.S. Starting could also be problematic and sometimes the battery would just go flat. All good now.

[Volvofreak2]

Oh, yes, groundconnection is always something to have an eye on. To clean them and put some batteriegrease on is always a good idea! After purchase of my 850 I found the main earth cable in the contition, shown on the picture. To me it is a miracle, that the engine still run, but it did. But after fixing it, the engine had reasonable more power and his 170 hp back!

Hej Gernot