Bit of a head scratcher?

[Deleted member 37751]

I have a 638 Vito that randomly will not start.

I can cover for example 50 miles, pull up, turn the engine off, go to turn the engine back on and it wont start, although it will try to turn over...
Other times it can be stood for days it will fire up first time like a brand new van

I've had the battery & alternator checked, but they came back fine? It has a hands-free kit attached that has power to it but doesn't work and it also has a towbar. Could one of these be draining the battery? Also, when I check the alternator and battery, the van will have been warmed up, will this give the effect of a false reading?

Any help would be appreciated, the problem is starting to grate...

 

[corned]

You flag the electrical system as a potential problem, but you haven't said anything about why you suspect this!

What we need to know is that when it doesn't start, does it crank over properly, or is it very sluggish and won't turn over properly?

If the starter turns properly, then there is no reason to suspect the battery/alternator. We would then be looking at fuelling or possibly glowplugs.

 

[A140driver]

Sounds like it may be flooding itself by getting too much fuel through possibly.

 

[Deleted member 37751]

You flag the electrical system as a potential problem, but you haven't said anything about why you suspect this!

What we need to know is that when it doesn't start, does it crank over properly, or is it very sluggish and won't turn over properly?

If the starter turns properly, then there is no reason to suspect the battery/alternator. We would then be looking at fuelling or possibly glowplugs.

I presumed electrical because of how random the starting problem is? Like I say, it's got me stumped..
It turns over very sluggish when it's having one of its fits...

 

[corned]

OK - thanks. So it does turn over slowly when this happens.

Does the V have the cluster info like other MB models? The reason I ask is that in the C, E and S classes (and more models I don't doubt) there is a reading in the instrument cluster which gives the battery voltage. If it has this, you may be able to monitor the voltage and see if there is any anomaly there when the starting problem happens?

Having said all that, my first port of call would be to check the engine earth strapping web(s). If not anchored very firmly at both ends this could cause starting issues, and could also provide the randomness you are experiencing.

 

[trapperjohn]

Maybe if you disconnected all the wires to the tow bar and all the wires to the handsfree set up and ran the van for a bit it could eliminate a though process

 

[jonathanc]

Personally I'd suspect the starter motor or the battery, if you can leave it for days and it will fire up that suggests that it isn't a (consistent) battery drain. When it is playing up, can you jump start it? If so that points to a battery issue in which case I'd replace the battery - sometimes they test fine but are really duff. My sister in law had a honda that would sometimes loose charge, battery checked OK when tested but then the car wouldn't start. They changed the battery and it has been fine since.

 

[Deleted member 37751]

It jump starts fine.
I think I'll start with the battery and see how we go from there

 

[camerafodder]

Possibly starter motor or dicky earth.