Technical Ducato starting problem - not the usual

[Googlebot]

i have only ever put the clips on to the battery terminals, but, also worth noting, the noco is not a big one for a moho, ie. a large diesel engine, so perhaps if the vehicle battery was a little low on juice, the noco may not have enough umph to fire it up?

If the battery is good, the Noco will help it along regardless.

Not sure if using the jump start points would help eliminate poor connections to the battery. Suppose you might need to connect the negative directly to the engine.

You risk frying stuff though.

I am sure others will know more to advise.

 

[Blueywr1]

I would replace the earth straps, the test won’t replicate starter current trying to pass through them and it’s cheap and easy.

Alternatively use a jump lead to create a temporary one and see if that works.

Sounds like an electrical problem to me and the bumping of the engine is sorting it.

the vehicle is currently at my home and before i put it back in to storage until the new year - when i agreed with the garage that they could keep it indefinitely - i am beginning to think i may attempt to replace these. i am no mechanic, but i am a property handyman, so have some skills and plenty of tools. it may be above my pay grade, but i'm willing to have a look .
does anyone have a link to the suitable earth leads i would need please? all i seem to find are really short.
thanks

 

[Googlebot]

Here you go.

Build your Battery Cable

Speeding - Performance parts - We supply Europés leading fuel systems, The widest range of AN-fittings, AN-hose, Turbos and accessories

www.speedingparts.co.uk

 

[Blueywr1]

Here you go.

Build your Battery Cable

Speeding - Performance parts - We supply Europés leading fuel systems, The widest range of AN-fittings, AN-hose, Turbos and accessories

www.speedingparts.co.uk

10mm i assume, or is this just a personal preference?
i'll obviously need to measure the length quite precisely if i am to purchase with the lug pre-fitted.

 

[Googlebot]

10mm i assume, or is this just a personal preference?
i'll obviously need to measure the length quite precisely if i am to purchase with the lug pre-fitted.

I would go for at least 25mm.

Some would say that’s overkill, I like to have plenty of spare capacity.

 

[Blueywr1]

I would go for at least 25mm.

Some would say that’s overkill, I like to have plenty of spare capacity.

ah ok.
the site you sent sell 10, 16, 35 and 50 by the meter.

 

[Blueywr1]

ah but, there's one link that is labelled 16 and it lists 25mm cables, so it looks like they have a problem!

 

[Googlebot]

Bigger isn’t always better, but with cable, it usually is.

 

[Communicator]

Crank turned slowly will enable all of starter ring gear to be examined , slow turning enables any compression to leak past piston / rings

Though if ring gear damaged I would expect to hear starter just spinning rather than a click

I am ready to defer to greater experience, but in my own encounters with pre-engaged starters the pinion has to engage, to allow the solenoid to complete its travel, and close the contacts. This is what I interpret pre-engaged to mean. The motor should not just spin.

 

[jackwhoo]

I am ready to defer to greater experience, but in my own encounters with pre-engaged starters the pinion has to engage, to allow the solenoid to complete its travel, and close the contacts. This is what I interpret pre-engaged to mean. The motor should not just spin.

I totally agree with you , but if the ring gear is damaged/missing tooth the pinion will travel fully out engaging the motor contacts but the pinion will have nothing to push against and so soon freely

Perhaps the ring gear is damaged so the pinion will not travel out fully? No one currently knows.

 

[Communicator]

10mm i assume, or is this just a personal preference?
i'll obviously need to measure the length quite precisely if i am to purchase with the lug pre-fitted.

Fiat eLearn gives 35 sq mm for the positive lead to the starter motor, and 50 sq mm for the battery negative connection, though from inspection of my own 2006 2,8jtd, i think that the negative could be 35 sq mm.

Handling such large cables is not a simple task. If the cables have been examined and there is no visible damage or corrosion, I would not rush headlong into changing the cables .

 

[Communicator]

I totally agree with you , but if the ring gear is damaged/missing tooth the pinion will travel fully out engaging the motor contacts but the pinion will have nothing to push against

Perhaps the ring gear is damaged so the pinion will not travel out fully? No one currently knows.

That was my thinking.

Another possibility to eliminate is a broken, or otherwise faulty battery positive clamp. There are a few reported instances of cracked positive clamps, which are integral with the battery fuseboard.

 

[jackwhoo]

Or there could be a problem with the positive wire connection at the starter motor end , or under the insulation

 

[Communicator]

Or there could be a problem with the positive wire connection at the starter motor end , or under the insulation

Or marginal high resistance connection to solenoid. I had something similar years ago. Would just click when engine hot, no problem when cold. Eventually decided it was due to increased resistance of solenoid when hot, coupled with other factors.

 

[jackwhoo]

this one has already had two new starters and fault remains.
Jump lead test needs to be done and all the other suggestions

 

[jackwhoo]

Interesting thought that it could be dodgy trigger wire / connection allowing some current flow to cause click but insufficient to operate the high current switch built in to starter

 

[Anthony489]

I think all this talk about main starter connections, earth straps and booster packs may be barking up the wrong tree.

If I have understood the situation correctly, the starter solenoid clicks but the starter motor doesn't turn. If this is the case, there is no heavy starter current flowing, so the state of the main starter feed wire and the earth return is not of great importance. If the engine turns over fine on at least some occasions it suggests there isn't much wrong with this circuit.

As I suggested earlier, Step 1 is to test the solenoid initial current to see if it is normal, i.e. 20 to 30 Amps. If it's low there is an electrical problem in the solenoid or its feed circuit which needs to be investigated. If it's normal it suggests a mechanical problem preventing full pinion engagement.

 

[Blueywr1]

Is "step 1" something I could attempt with a multimeter? If so, how? Thanks

 

[Anthony489]

Hi. Most multimeters only handle up to 10 Amps on their highest DC current range, but if you can find one with a high enough rating you need to connect it in series with the solenoid feed cable. This needs removal of the feed cable at the solenoid and connecting the meter "across the gap". A garage would use a "clamp-on" type current meter, as their jaws just go around the cable without undoing anything which is a lot less hassle.

The alternative is a partial test of the wiring to the solenoid by checking the voltage at the solenoid terminal. This is not a conclusive test as it doesnt test the solenoid itself, but it can show if there is excessive resistance in the solenoid feed circuit. Wire a multimeter on a suitable DC voltage range between the solenoid feed terminal (right at the solenoid body) and the engine block. You should see something near battery voltage when the key is turned to the start position. If you see too low a voltage it indicates excessive resistance (poor connection etc) somewhere along the line or even in the ignition switch itself.

 

[The Panda Nut]

Generally they stop in one of two positions, as in two pistons up and two down.
So to prove if starter ring gear worn in either of those positions you may need only move the crank a small amount to check.
Way back in the old days it was not unheard of for someone to remove the ring gear and move it to a different spot
I have fitted many new ring gears in the past , however it was in the days of inertia starters rather than the modern pre engaged design which generally doesn't cause that wear, as it engages and then turns, rather than spining and "smashing" it's way in to engagement.
I see from OPs original comments it was mentioned putting vehicle into 4th gear and slightly moving had the affect of permitting engine to start, so although unusual it may be possible ring gear is damaged in one spot.
The only time I have seen that was where a S/H engine that had been standing in a yard rusting and was fitted without care re ring gear.

I will say that back on 1990 we had a similar issue with our Uno. It was only when I went and bought a genuine Fiat starter motor it stopped. I was never aware of why it did this. I never entirely trust new bits until they prove themselves and if I get a faulty part or battery now, I go somewhere else for a 2nd replacement so I dont get caught by bad batches.

I like your suggestion of turning the ring gear. A bit outside my range of ability digging the flywheel out now and back then I didnt have the time.