Mercedes Sluggish Starting

My MB has always started quickly in a second or so. Picked up the van from storage 2 days ago, started fine, filled with fuel, started fine, drove home and parked. Put onto EHU to top upp the engine battery as had been stood for 5 weeks. Today when I tried to start for my trip to Wharfedale, churned over at normal speed but would not fire, step buzzer going though step was retracted. After 20 seconds or so, engine started and runs ok, buzzer off. I drove 80 miles and stopped for coffee/loo, same happened, slow to start with buzzer. Next stop didn't extend step but same action. Once started no warning lights are showing.

Any ideas? Appears engine module not recieving step retracted signal? Step works fine manually extending and retracting on the button.

Hi
  I always wait until the ignition lights have gone out to engage the starter,I am presuming the glow plugs have warmed the engine and it then starts,could it be the glowplugs have stopped working does it restart easily when hot
regards
Alan

Doen't seem to make any difference, hot or cold. Same problem having driven 100 miles, stop and restart with in a few minutes, still sluggish.

gemdeco wrote:Hi
  I always wait until the ignition lights have gone out to engage the starter,I am presuming the glow plugs have warmed the engine and it then starts,could it be the glowplugs have stopped working does it restart easily when hot
regards
Alan

One of those lights are the glow plugs they all go off together(ignition lights) like a Christmas tree when you turn on the ignition.

I belong to a sprinter forum part of MB forum might be worth looking on there if you don't get the answer here

Update:

Parked up in Wharfedale CMC site. Gave the grey relay, referred to by Peter #1, a wiggle in its seating. Vehicle battery on charge through EHU overnight, next day engine started first thing, no problems. Tried another couple of times over 4 days, starts fine. Started this morning, and drove to Meathop CMC site, stopped once onway, starting problem returned. Voltage checked whilst travelling was 14.1v through cig lighter socket, so alternator seems OK.

Parked up and volts reading 12.5v after 2 hours, but drops rapidly to 12.1v if headlights put on, and back to 12.5v when switched off, so I think the battery is the culprit. It is not the OEM battery but a Platinum Prestige Plus 100AH, must have been changed before I bought in 2014. Any comments in confirmation?

Can any body confirm the dimensions of battery required. This looks about right but..https://www.tayna.co.uk/019-Enduroline-Car-Battery-P8385.html

Thanks Peter, knew you would come up trumps. Do you agree that the battery is the culprit?

Coming rather late to this discussion; firstly, the leisure battery has nothing to do with your problem; have you replaced the 2011 main battery on your van? If not, you have done well! These things are not like car batteries... or even commercial vehicle batteries, which tend to get bashed every day and get used and topped up, whereas we olde-hippy folks might have ours sitting dormant for days/weeks/months.

After a life-time in motor-sports/camping/boating/running old bangers at college there is no finer feeling than fitting a new battery- after all, the cost is a fraction of the pleasure. ;-)

Peter Brown wrote:I do wish that people would read the thread before making redundant comments.

Does this mean that once a staff member has commented all further comments are redundant !! ??

Update. Fitted new Yuasa battery as suggested by Peter B. https://www.tayna.co.uk/YBX5019-Yuasa-Silver-High-Performance-Car-Battery-HSB019-P10713.html
Engine now starts as normal after standing, so hopefully problem solved.