Ducato voltage drop

[pike]

Hi, my 2013 Fiat Ducato based motorhome currently has a problem starting. Despite the battery being fully charged (checked with a multimeter, and the control panel also shows this) when I put the key in the ignition, the control panel shows the voltage dropping to around 11v before slowly recovering to the 12.6/12.8v shown before the ignition was on (just ignition, not engine running).

 

If I try to start it, it won't, unless I wait a couple of minutes for the voltage to come back up again. The actual battery voltage isn't dropping and recovering though, it remains full, just what is shown on the control panel.

 

I have tried a different battery and this still happens: could it be an earth fault or any other ideas?

 

When the engine is running, the battery shows 14.4v so the alternator seems ok.

 

I would say it is an intermittent fault (as in it usually does start), however perhaps I don't usually try to start the engine immediately after turning on the ignition - taking time to strap in the kids etc. Maybe it always does this and I don't notice: it was only today when I looked at the control panel that I saw the voltage drop then rise again.

 

The other day I had driven around 50 miles and stopped for fuel. When I tried to start, there was no power at all - even the dashboard didn't light. I don't know if it really helped as I disconnected the negative battery lead and reconnected and the van started first time....

[Tracker]

Poo quality and badly connecting earth straps are a known issue with Sevel vans and can provoke all manner of strange effects, and there have been several threads on this.

The generally accepted cure is to add a second earth strap from a clean and paint free point on the engine block to a clean and paint free point on the chassis.

There are many options for a suitable lead but I used a black Halfords - or any other motor store - 24" battery lead which was easily obtainable and came with ring terminals each end for easy fitting under existing bolts/nuts/washers.

This may or may not be your issue but it would at least be one variable less to worry about!

[tonyishuk]

Maybe something as simple as the battery connectors not being as tight as they should be.

 

I have a range of experiences where the car started ok with the connector loose, but stopped after going over a bump when the connector bounced off the pillar, to a battery that showed on various tests to be ok, just failed to muster enough amps to turn the engine over. The latter being A four litre diesel.

 

But changing the battery should show up faults like loose clips.

 

Any change in behaviour if you use the jump start as a test ? This may overcome the earth strap problem.

 

Disconnect the habitation battery before a jump start, as the charging electronics may suffer.

 

Cou ld be a lost winding on the starter motor ?

 

Rgds

 

 

[aandncaravan]

It is unlikely to be the battery, as they tend to be poor or good. They won't be dead one minute and start the vehicle the next.

 

To have no lights at all on the Dashboard one minute and the engine start the next also pretty much rules out a Starter issue, unless you have two problems.

 

So the most likely culprits are Poor connections : battery clamps, Earths or Ignition switch/key issues.

 

Like Tracker says, I would start with Earth strap as by design they tend to have a limited life and it is the cheapest to address.

 

If that doesn't fix it and all other connections look good, then get the Ignition switch checked.

 

Earthing is the most likely issue and you will find lots of help here :

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Ducato-X250-2-3-Multijet-Earth-Strap/48885/

 

.

[laimeduck]

Test the earth by connecting a jump lead from the battery -ve terminal to the engine or gearbox. 

If the earth is the issue then the symptoms should disappear.