Technical multijet sometimes not starting. Low voltage at solenoid trigger.

[Paul Jaggard]

After 190k miles in 17 years, finally a serious problem.
A few weeks ago, catastrophic clutch failure...required a new gearbox too.
A severe thumping, using a solid towing-bar, resulting in the towing hook tearing off the metal mounting, and plastic bumper.
Usual garage too busy, so neighbour replaced clutch and box.
Everything seemed ok, (although there was a very small thumping sound just as the engine caught)
OK for a time, then after a long hot journey, wouldn't start.
The fault has recurred sometimes since. After waiting a few hours it starts again.

I've since added a secondary earth from battery to engine, and thought that this had solved my problem

Now, usually it starts fine, but sometimes it acts as if there is only a low voltage getting to the solenoid trigger.
I've noticed that the tank fuel pump doesn't turn off after a few seconds like it should.

I've had 1 blown 20a ignition switch, fuse a week or two ago. (maybe I left the ignition switch on too long when the engine wouldn't start?)
Today, I've discovered that if I put on the interior light, then turn the ignition switch to its second position, if it dims slightly then the engine will start.
However if it dims a lot (to around 6v) and the solenoid sounds feeble, then it won't start.
I've had the starter off, and it always works fine on the bench (though I have to push the interior solenoid button with something harder than my finger to give continuity at the main contacts.
My Haynes circuit diagram takes 2 wires from the second position of the switch. One via engine compartment fusebox, and "short circuit coupling" (whatever that is), to the ECU.
And the other via passenger fusebox to Body Control Unit.
The interior light seems to get its power from the body control unit.

Why would my ignition switch give this low voltage, and will I have to dismantle the steering wheel to get at it?
Or is the problem elsewhere? ECU? BCU? Relay?
I noticed that my neighbour was much rougher manhandling the ECU cables than I would dare be, but unplugging, and reinserting them didn't help.

After 17 years virtually trouble free, it has come as a bit of a shock to have these problems all at once!

Has anyone else experienced anything similar, or have any suggestions?

 

[Paul Jaggard]

Dog bone pic

 

[koalar]

That looks like the arrow end

It should have holes around it

If you push the ends up and down an there is very little movement then it's fine

 

[koalar]

While it's failing can measure a few thing

What are the revs, we know that 1 and 3/4 marks on the rev counter is fine

If it's not up to speed we can check

Voltage going to the solenoid, is it constant, or is it intetmitant.

Voltage drop, from the battery positive lead to starter post,

Obviously if it's spinning fine but not firing up we need to be looking elsewhere

 

[Paul Jaggard]

I eventually got it to almost fail to start. Battery voltage is a bit low at 12.4v
Voltage drop negative terminal to engine block was still around 0.1v
Voltage drop positive terminal to solenoid post, while cranking 0.1v
I hung a wire from the solenoid so that I could check the voltage to the primary when cranking.
It was cranking rather poorly, but did start, however I held the ignition on for a few more seconds (hopefully the one way clutch in the starter worked ok),to see what the voltage got up to. about 8v only. but of course it was still cranking.
It blew the ignition fuse again.

Maybe it is time to re-order that starter motor, and try fitting that...maybe another £60 ....?
Once I've decided to do that, I think I'll take the solenoid off, and cut it open, to see what the contacts are like.

 

[The Panda Nut]

My recent failed battery usefully appeared to have 12.9v but was as dead as a door nail. The indicators on oyur seemto suggest the battery....
Has the starter ver been changed after 17 years it is probably on borrowed time. Glow plugs always come on as fer as I am aware they just have less to do if its much warmer.When our battery went we had a little trouble and odd occasions when it wouldnt start before it ided totally. There is no rhyme or reason to batteries failing, Mostly they do the job for a number of years and then fail but some fail much earlier than others and in an odd way. If you get the sort of readings I did its difficult to believe. I swapped batteries from our other car and the second one failed too so I thought it was the car to blame. It was just both batteries failed in the same week. Multicell 5 Barrow Close Norwich offer free battery testing. (near Wickes)

 

[koalar]

We substituted the battery so it's not that

We test the alternator as much as easily check so it's unlikely

I eventually got it to almost fail to start. Battery voltage is a bit low at 12.4v

When the battery gets this low it will struggle to start Anyhow, it needs good crank speed to build the fuel pressure properly

Voltage drop negative terminal to engine block was still around 0.1v

A good result, negative lead is okay

Voltage drop positive terminal to solenoid post, while cranking 0.1v

Great result the positive lead is okay

I hung a wire from the solenoid so that I could check the voltage to the primary when cranking.
It was cranking rather poorly, but did start, however I held the ignition on for a few more seconds (hopefully the one way clutch in the starter worked ok),to see what the voltage got up to. about 8v only. but of course it was still cranking.
It blew the ignition fuse again.

Shouldn't blow so quickly looks to me the problem may be here

panda 1.2 diesel | FIAT Panda (Mk3)

ignition switch fuse f23 blows sometimes all instuments dont display :mad: have to replace it to start car recently after changing fuse again noticed clicking and no starter working after a few turns of key it starts please can anyone help

www.fiatforum.com

Maybe it is time to re-order that starter motor, and try fitting that...maybe another £60 ....?
Once I've decided to do that, I think I'll take the solenoid off, and cut it open, to see what the contacts are like.

Possibly

But it would be a big coincidence it went at the same time at other work was done

 

[Paul Jaggard]

I tried something new. And don't understand what's happening. Just before this test, the car was starting, but rather erratically, after a short drive.
I have that cable dangling from the trigger point on the solenoid. Disconnected the braided cable between the solenoid and motor, and put a multimeter across the battery, and another between battery -ve, and the solenoid trigger. When turning the ignition on, the battery voltage drops from 12.5 to 11.8, then after 16secs, when the fuel pump cuts out, 12.4v. Turn the key to start and voltage drops to 12.22. At this point the voltage at the trigger jumps from 0 to 11.22v
This all seems normal, but the solenoid does not click in.... however many times I turn the key. I thought that it would, 11 volts to one side of the coil, and earth to the other?
Reconnect the braided wire, and the engine turns over again...

 

[Paul Jaggard]

Has anyone any idea as to why the solenoid doesn't click?
Looking at the circuit diagram, the only EXTRA circuit made, when the ignition is set to start, is the solenoid coil. So presumably it must be this, or its wiring that is causing the fuse to blow, when holding the starter on for a long time.

 

[koalar]

Has anyone any idea as to why the solenoid doesn't click?
Looking at the circuit diagram, the only EXTRA circuit made, when the ignition is set to start, is the solenoid coil. So presumably it must be this, or its wiring that is causing the fuse to blow, when holding the starter on for a long time.

The pull in winding high amperage is normally connected to the motor

Disconnected it will not work

The hold winding lower amperage is normally connected to the starter case

I say normally as I haven't taken a panda diesel starter apart

The wiring diagrams are simplified

It does not show everything that goes on inside a module just the wiring to and from them

As soon as contacts to the motor close the high amp windings are disconnected automaticly as both sides are now 12v no potential difference

 

[Paul Jaggard]

Thanks for that, I didn't realise that it wasn't just a simple coil pulling in a copper bar. I've looked it up, and found a simple wiring diagram, which together with your description helps me now understand how it works, and why it doesn't click in, when not connected to the motor.
Maybe a LITTLE knowledge is a dangerous thing!
Looking at the diagram, maybe if there was an intermittent fault on the hold in winding, that would explain the symptoms?

Our Ukrainian lady is going to need her car back in a few days, if we can't get it sorted, we'll have to buy another car.
As a last throw of the dice, I'll order a new starter tomorrow.
Unless you have any other suggestions as to what to try?
It is so difficult to get anyone to sort it, promptly when it is such an intermittent fault.

Thanks again for your patient help.

 

[koalar]

A quick summery

We have tested the earth under load

We have tested the postitve lead under load

We have substuted the battery

We have tested the alternator under load

We know the car suffered a catastrophic clutch which resulted in needing a new gearbox as well

F23 has blown twice

We can hear the pinion gear intermittently disingaging and rengaging while cranking

Works fine when cold on a fully charged battery, but fails when hot fully charged battery

Unfortunately I have never had this exact fault, so don't have of a definitive way to diagnose the problem

I wouldn't have a problem fitting a second hand starter my local breakers charged me £15 about 5 years ago

The diesel is not the same as the 1.1 or 1.2, but it's likely to be the same as other fiat 1.3 of the same age, I took one off a punto grande

We have come to a stage where I can't think of any more simple safe easy tests

I know what I do but it's a bit sketchy. With a fully charged battery and a hot engine failing to turn over properly, I would directly apply battery voltage to the solenoid via a lead with a 20A fuse in it.

 

[Paul Jaggard]

That is a good summary. thank you for putting it so succinctly.
I ordered a new starter for delivery tomorrow...fingers crossed.
I have been loathe to connect a lead straight to the solenoid, because I didn't know if it was safe to do so with just the ignition switched on, though I can see no reason why not. I would like to try that though!

 

[koalar]

Thought I would post this slowed down video, mainly it shows a different approach

There is still good cranking speed and voltage

You can hear the clunk of the pinion hitting the ring gear several times and hear a pause, while seeing the volts rise and revs fall

I myself don't like using a jumper in to what could be a faulty circuit,

All a waste of time as the gun us already pulled on a replacement starter

Fingers crossed and good luck

 

[Paul Jaggard]

My fingers ache from being crossed.
Having done it before, it only took me 11/4 hrs to replace the starter.
The new starter seems to have solved the problem.
We've not been on any journeys over 20 miles, and the weather is now colder, but it has so far started promptly every time.

My sincere thanks to all who have left helpful comments, especially Koalar. I've learned a lot. Previously, with no real problems, I'd become complacent!

My thoughts are that we had an intermittent temperature related problem with the hold in coil of the solenoid (which I didn't even know existed).
When it was not connected properly, the pull in coil would connect the main terminals of the solenoid, which immediately stopped the pull in coil working, leading to the main terminals disconnecting. This oscillation would mean that while there was current getting to the starter, it was intermittent, and behaved as if it was a flat battery.......?

I'm tempted to put the old starter in a low oven, and see if it fails!...it was always cold when I bench tested it, probably 40 times.

Koalar, this thread has got very long, and for most, probably boring. I had some difficulty, as an amateur, learning how to change the starter motor. Would it be useful to anyone for me to give a few pointers on it? Should I start a new thread "changing a panda multijet starter motor"

I still don't quite understand why we had the first problem with it not starting. A hot day in France. 100+miles towing250kg @ 50mph. Stop for 20 minutes. Car cranks fine, but won't start. Try several times. 2 hours later and starts ok.
After that the symptoms were poor cranking speed, leading to not starting.
I don't know how the ECU works, but is it possible that when stopping, the water pump stops cooling the engine, which then means the water temperature rises, and temperature sensor somewhere causes the ecu to stop supplying fuel.....?

 

[koalar]

My fingers ache from being crossed.
Having done it before, it only took me 11/4 hrs to replace the starter.

Its not too bad, just awkward, I have changed the petrol ones from the top at the road side. It a bit iffy as you have to undo the cables while it's out and balanced, if it drops there is a chance to damage the smaller wire

The new starter seems to have solved the problem.
We've not been on any journeys over 20 miles, and the weather is now colder, but it has so far started promptly every time.

Fingers crossed

My thoughts are that we had an intermittent temperature related problem with the hold in coil of the solenoid (which I didn't even know existed).

Does sound like it's disingaging for a fraction of a second

When it was not connected properly, the pull in coil would connect the main terminals of the solenoid, which immediately stopped the pull in coil working, leading to the main terminals disconnecting. This oscillation would mean that while there was current getting to the starter, it was intermittent, and behaved as if it was a flat battery.......?

Sounds possible to me

I'm tempted to put the old starter in a low oven, and see if it fails!...it was always cold when I bench tested it, probably 40 times.

Koalar, this thread has got very long, and for most, probably boring. I had some difficulty, as an amateur, learning how to change the starter motor. Would it be useful to anyone for me to give a few pointers on it? Should I start a new thread "changing a panda multijet starter motor"

Not boring, interesting, the starters rarely fail on the Panda, I have seen poor starting on a deisel due to it getting lazy, and not turning quick enough, I have never heard the pinion coming out of mesh while it's spinning before. Yes if you have tips on changing the starter post them.

I still don't quite understand why we had the first problem with it not starting. A hot day in France. 100+miles towing250kg @ 50mph. Stop for 20 minutes. Car cranks fine, but won't start. Try several times. 2 hours later and starts ok.

Without the data from the sensors we will probably never know

After that the symptoms were poor cranking speed, leading to not starting.
I don't know how the ECU works, but is it possible that when stopping, the water pump stops cooling the engine, which then means the water temperature rises, and temperature sensor somewhere causes the ecu to stop supplying fuel.....?

I'd be interested in what the Crank speed is now, the original videos show just over one and a half marks on the rev counter

Around 160-170 RPM does the new starter alter this