Starting problem

Hi there, I am new to the forum, I have owned Hijets and more recently Piaggio porters for the last 7 years and think they are fab!
I currently have 7 on the road and 2 for donor parts, and use them for my business, as cheap to run, insure and generally much more reliable than any other micro vans I have come into contact with.
I have a new problem, which my garage haven't been able to diagnose unfortunately as it never happens when its with them!
2 of my Piaggio's, both started over last few weeks when you turn the ignition just get a dull click, then mostly start normally after the 2nd attempt, however the problem is intermittent and can happen some days on multiple starts, and on other days nothing!
I don't think the atmospheric temperature has anything to do with it as can happen early in the morning or midday heat.
Fuel isn't an issue as not from same petrol station.
Twice changed starter motors from my donor vehicles, and electrics replaced from battery to starter, still the problem persists. My father in law has just come in for dinner, weirdly today his Piaggio has started doing the exact same thing.
None of them over heat, all regularly serviced etc.
Am reluctant to drive the 40 miles to put on diagnostic machine as will only show up a problem if happens there, and it could be having a good day, so I am wondering if anyone on here has had the same issue and found a solution?
Thanks for you help in advance.

My Guess is Key switch, you can use one off the doner, you don't need to change the key barrel just the unplug the loom under the dash and undo the tiny screw that holds the plug into the barrel

Welcome LTD, and respect for your fleet! Could be that switch - I'd test by removing it from the barrel and turning with a screwdriver. Usually more of a connection problem, it's weird you have it on several vehicles at the same time. I have 4 vans and never experienced tbis without battery or wiring trouble so suspect it somehow related to your servicing regime - but can't think what

Where in the country are you?.

Welcome to the forum. The thinner wires on the positive battery terminal corrode, its worth checking those. Give them a good pull to see if one breaks.

I would go for the two wires on the live battery terminal too.

Welcome to the forum.

Not so sure a diagnostic machine would pick this up anyway.

Where abouts are you?

HighlyJetted wrote:I would go for the two wires on the live battery terminal too.

Possible, but on 3 at similar time sounds fishy - especially as they start 2nd (or so) time and no total fails as yet. I'm wondering if there's a common denominator in whoever services them, or something they use. Plus the OP stated electrics replaced from battery to starter - surely the small wire would have broken/been discovered by now?

Hi Guys, thank you so much for the advise, after which I asked the mechanic to change the ignition switch on one of them then ran it around for a week and hey presto it worked! A 10 minute job on them, thank god for the donor vehicles yet again, and we are reliably back on the road.
We are in Wiltshire, I think the problem although weird all happened at the same time, is because we do so many short journeys in a day, normally only cover 8 miles but may include 5 starts, we had just worn the buggars out, however the good old trusty Hijets even the oldest 1 being 14 years old, have never suffered this problem.
Thanks again

thanx for the update/aftermath
that makes this topic more helpfull if people post the endresult to