Technical Ducato starting problem - not the usual

[Blueywr1]

I mentioned it in my first post.
At that point I had disconnected the sigma and fiat immobiliser, but as this made no difference, I reconnected them.

 

[bugsymike]

Doh! I do not remember previous mention of an immobiliser, but this could well be the cause of the problem, as some alarm systems used to interrupt the solenoid circuit. If you have to key a code into the alarm, in order to allow the engine to crank, then the alarm has contacts in the solenoid circuit.

I agree with @Communicator re "Sigma" , over the years I have had loads of aftermarket alarm systems cause problems, they seem to fail even more than genuine factory versions.

 

[Blueywr1]

With the 12V power being disconnected from it though, at the actual control box I found buried under the dash, I would have thought this would have disabled it.
It certainly kills the keypad, so it'll start - when it wants to - without entering the code.
With it connected, after entering the correct code, we can hear a click from its location in the dash, followed by the fuel pump prime.

 

[Anthony489]

Hi again

I have been pondering this, and apologies if this conjecture is wrong. The current you have measured into the starter solenoid (about 30 Amps) is at first sight reasonably high. However, should the immobiliser have been connected somewhere in series with this circuit, it's possible that the extra wiring and a set of closed relay contacts (immobiliser not powered, immobiliser relay not energised) could be introducing a bit of unwanted extra resistance. If so, the 30 Amps might be borderline for operating the solenoid. Some of the examples of so-called professional immobiliser installation we have seen on this forum over the years have been a bit eyebrow raising.

I suggest you trace the solenoid wiring back from the solenoid to determine once and for all if the wiring is standard or modified as above. Alternatively, take a heavy gauge wire direct from the battery positive and carefully apply it to the solenoid terminal with the ammeter clamped round it. You may find that the current is more than 30 Amps in that instance.

 

[Communicator]

Hi again

I have been pondering this, and apologies if this conjecture is wrong. The current you have measured into the starter solenoid (about 30 Amps) is at first sight reasonably high. However, should the immobiliser have been connected somewhere in series with this circuit, it's possible that the extra wiring and a set of closed relay contacts (immobiliser not powered, immobiliser relay not energised) could be introducing a bit of unwanted extra resistance. If so, the 30 Amps might be borderline for operating the solenoid. Some of the examples of so-called professional immobiliser installation we have seen on this forum over the years have been a bit eyebrow raising.

I suggest you trace the solenoid wiring back from the solenoid to determine once and for all if the wiring is standard or modified as above. Alternatively, take a heavy gauge wire direct from the battery positive and carefully apply it to the solenoid terminal with the ammeter clamped round it. You may find that the current is more than 30 Amps in that instance.

I can relate that statement to the alarm installation on my own 2.8jtd.

The second paragraph above is again similar to my modified "pliers" method proposed in #76, excepting that I was careful to suggest a method that did not include any possibility of creating sparks close to the battery, which may have been gassing.

I am also considering how to confirm the presence or abscence an alarm relay contact in the solenoid circuit on my own similar vehicle, which I believe had 3 failures to crank. On my vehicle the alarm links into the central locking, so it is always unset when trying to activate the starter via the key, Perhaps if I run a test wire via the door seal, I could test the connection from the ignition switch connector to the starter solenoid terminal, with alarm set. For me this may be easier than wire tracing.

May I also repeat my experience with a Talbot Express many years ago. I added an alarm system, and a hidden switch into the solenoid circuit. All functioned OK until I started getting just a clunk from the starter but only when the engine was hot. I reasoned that increase of the solenoid resistance with temperature was the problem. (The starter was above the turbo, and had a heat shield.) The cure was a starter solenoid relay, which was easy to fit. I subsequently read of others experiencing identical problems.

 

[Mike1alike]

That's a very specific problem you have there and you were left with it after you replaced all those parts. None of them was the fix, putting those new parts just masked the problem, but it is still there and it's the same.
So... what could it be?!
The starter works by having 3 lines connected. One is the (-) connection made through the casing and that is definitely ok at yours, by what you said, and there are 2 (+) 12 V connections. One is that little wire that is fed when you turn te key on and with your new ignition and measured amps that sounds to be ok and the other one is the permanently connected 12 V, the line that also connects the alternator with the battery. So you have to check that line, the wiring inside cable migh be broken or oxidized contacts.

When it wouldn't start, whilst trying to watch the reading on the meter, the click I could hear is much higher up in the engine bay and I would guess at saying from the fuse box.

So it's possible there might be a starting relay. If there is, there's where it sits, in that fuse box and they do click when activated.

 

[Blueywr1]

I should say, the click we hear from the sigma unit is much less severe / loud than the click we hear from the engine bay, when it won't start. It's a very much a gentler click, then immediately we hear the fuel pump. The click from the Sigma unit can always be heard - after entering the code correctly - whether the vehicle starts or not.
The, "none starting problem" is not temperature related. It happens both when stone cold and when warm.
We do not have central locking - the vehicle has only one entrance door.

I clearly need to do the, "pliers / similar" test. I'll use @Anthony489 quote for reference, but I would like to clarify so to do it correctly........

Alternatively, take a heavy gauge wire direct from the battery positive and carefully apply it to the solenoid terminal with the ammeter clamped round it. You may find that the current is more than 30 Amps in that instance.

1) Disconnect neg battery terminal
2) Attach wire from pos battery terminal and connect to thin wire on starter motor
3) Reconnect the neg battery terminal

Question:
Will it attempt to start after doing 2, or does sigma immobiliser code need entering and the key need to be turned?

Depending on the answer, for me to clamp around the wire, I will require wifey.

Thanks guys

 

[Blueywr1]

Worth also informing you............

Yesterday I checked the voltage of:
1) battery - across pos and neg terminals
2) pos battery to earth flag

Engine was off.

I got the same voltage reading. If my test leads are long enough to get to the starter motor, I will do this with wifey next weekend.


With engine on, battery voltage was 14+V, so alternator appears good.

I also tested resistance:
1) neg battery terminal to earth flag

No difference.
Again, if leads long enough, I will try to get to the starter motor next weekend.

 

[Communicator]

That's a very specific problem you have there and you were left with it after you replaced all those parts. None of them was the fix, putting those new parts just masked the problem, but it is still there and it's the same.
So... what could it be?!
The starter works by having 3 lines connected. One is the (-) connection made through the casing and that is definitely ok at yours, by what you said, and there are 2 (+) 12 V connections. One is that little wire that is fed when you turn te key on and with your new ignition and measured amps that sounds to be ok and the other one is the permanently connected 12 V, the line that also connects the alternator with the battery. So you have to check that line, the wiring inside cable migh be broken or oxidized contacts.

So it's possible there might be a starting relay. If there is, there's where it sits, in that fuse box and they do click when activated.

A starting relay is not shown in the standard wiring diagram. The only spare location in the engine bay fusebox is allocated to the starter interlock for automatic transmission. The solenoid connection is routed via the engine bay fusebox. I have often wondered............

 

[Communicator]

I should say, the click we hear from the sigma unit is much less severe / loud than the click we hear from the engine bay, when it won't start. It's a very much a gentler click, then immediately we hear the fuel pump. The click from the Sigma unit can always be heard - after entering the code correctly - whether the vehicle starts or not.
The, "none starting problem" is not temperature related. It happens both when stone cold and when warm.
We do not have central locking - the vehicle has only one entrance door.

I clearly need to do the, "pliers / similar" test. I'll use @Anthony489 quote for reference, but I would like to clarify so to do it correctly........


1) Disconnect neg battery terminal
2) Attach wire from pos battery terminal and connect to thin wire on starter motor
3) Reconnect the neg battery terminal

Question:
Will it attempt to start after doing 2, or does sigma immobiliser code need entering and the key need to be turned?

Depending on the answer, for me to clamp around the wire, I will require wifey.

Thanks guys

To answer the question, the starter motor should operate as soon as the connection is made at the battery negative terminal.

The only way to sop the starter would then be by discnnecting the battery negative.

The test wire needs to secured to the small (M5) solenoid terminal. The original wire does not need to be connected. to the terminal for the test.

I would not crawl under the vehicle with a live 12V wire. My method outlined in post #76 was designed to be as safe as possible, and does not require assistance, provided that a secure connection can be made to the small terminal on the solenoid.

 

[Communicator]

Worth also informing you............

Yesterday I checked the voltage of:
1) battery - across pos and neg terminals
2) pos battery to earth flag

Engine was off.

I got the same voltage reading. If my test leads are long enough to get to the starter motor, I will do this with wifey next weekend.


With engine on, battery voltage was 14+V, so alternator appears good.

I also tested resistance:
1) neg battery terminal to earth flag

No difference.
Again, if leads long enough, I will try to get to the starter motor next weekend.

It is not possible to measure this resistance with a standard multimeter. The reistance is too low, and any residual current will affect the reading.

 

[Blueywr1]

To answer the question, the starter motor should operate as soon as the connection is made at the battery negative terminal.

The only way to sop the starter would then be by discnnecting the battery negative.

The test wire needs to secured to the small (M5) solenoid terminal. The original wire does not need to be connected. to the terminal for the test.

I would not crawl under the vehicle with a live 12V wire. My method outlined in post #76 was designed to be as safe as possible, and does not require assistance, provided that a secure connection can be made to the small terminal on the solenoid.

I will try this method this week then.
A suitable wire would be mains 240V socket wire?

 

[Mike1alike]

Question:
Will it attempt to start after doing 2

If you disconnect the negative terminal it won't try to start.
This is the test you should do

Unlike in the video, probably the tension dropping is not up there on the nut, but somewhere down the line of that constant 12 V line.

A starting relay is not shown in the standard wiring diagram.

Ok, so there's no starting relay, but what @Blueywr1 described he heard sounds definitely like a relay in the fuse box and it's probably the fuel pump relay. That means the starter solenoid did nothing although the key line 12 V was fed, meaning the cause of it is the constant 12 V line.

 

[Communicator]

I will try this method this week then.
A suitable wire would be mains 240V socket wire?

If the means the cable that connects to the rear of a 13A socket, then that is about the minimum. Expect it to get warm with repeated use. If you leave the ignition off, engine will not start. All that you are looking for is for the starter to engage and start cranking the engine. If you do it too many times without starting the engine, you will of course dischsrge the battery. Not a good thing to do.

 

[Blueywr1]

If the means the cable that connects to the rear of a 13A socket, then that is about the minimum. Expect it to get warm with repeated use. If you leave the ignition off, engine will not start. All that you are looking for is for the starter to engage and start cranking the engine. If you do it too many times without starting the engine, you will of course dischsrge the battery. Not a good thing to do.

Ok, perhaps cooker wire is a better suggestion

 

[Communicator]

Ok, perhaps cooker wire is a better suggestion

That's getting rather beefy, you would struggle to terminate at starter small stud without using cable lug or crimp.

 

[Blueywr1]

Afternoon

With battery negative disconnected, securely attach a length of perhaps 2.5mm insulated wire to the small starter solenoid terminal. Expose a very short length of the conductor at the remote end of the wire.
Remove cover from engine bay fusbox to expose the M6 input connection. Restore battery negative. Ensure neutral selected, and handbrake on.
With ignition off, dab exposed wire end onto fusebox feed cable lug. Starter should operate reliably, and no need to start the engine

@Communicator
Great instructions - thanks.
Indeed, this does start the vehicle.
Where does this leave me?

Before doing the above procedure, I tried starting it normally with the key and it wouldn't start; I just got the loud, single click.

Appreciate your help/guidance.

 

[Communicator]

Afternoon

@Communicator
Great instructions - thanks.
Indeed, this does start the vehicle.
Where does this leave me?

Before doing the above procedure, I tried starting it normally with the key and it wouldn't start; I just got the loud, single click.

Appreciate your help/guidance.

Please check/confirm that it starts, or at least sthe starter every time, to your satisfaction. Given recent history, perhaps three times in succession would eliminate any chance event.

I am suspicious that the Sigma alarm has a relay contact in the solenoid connection from the ignition switch. The presence of this hypothetical contact can be proved either by physical wire tracing, or continuity testing. If presen,t connections are most likely to be behind the RHS lower dashboard, eLearn diagram does not show any connectors between switch, and engine bay fusebox, which functions as a junction box, and again shows a straight through connection to the solenoid. This means that if relay contact exists, the wire will most probably been physically cut. An alternative would have been to extract the wire from the ignition switch connector, connect to Sigma unit, then run new wire to ignition switch. The wire tracing method has previously suggested by @Anthony489.
The alternative method that I am considering, is to carry out continuity tests between solenoid wire, and ignition switch connector. It does need at least one long test lead run out of cab via door seal, and perhaps a second lead to extend from the starter terminal. Test with alarm powered down, alarm off, alarm set, and alarm triggered. However having proved presence of contact, the point of insertion would still have to be located.

For convenience I am attaching my annoted copy of Fiat eLearn diagram E5010. Starter motor is at LHS of drawing, and ignition switch is at bottom.
Relevant wire is colour coded RN for red/black. It starts at contact A3 of the ignition switch, and eventually arrives at the M5 starter stud (B1).

Access to the wiring is facilitated by removing the lower dash.

 

[Blueywr1]

Thanks again.
Perhaps with my excitement of the test starting the vehicle, I failed to add the following, which may / may not be relevant:

1) I tested it 4 times & it started immediately on every occasion.
2) To get it it to start though, I had to turn the key to stage 2 and then enter the code in to the sigma keypad. It would not start without doing this.
3) I had disconnected the thin (red/black) wire at the starter motor (and replaced it with my "made-up wire").
4) I reconnected the thin wire and the neg battery terminal and attempted to start with the key - no joy.
5) I have now put the vehicle battery on charge overnight and plan to return tomorrow AM to repeat the test a few more times.
6) Whilst I was there and before I did this procedure, I tried the jump lead from neg battery to engine lifting bracket - it didn't start and just heard the single click.

 

[Communicator]

Thanks again.
Perhaps with my excitement of the test starting the vehicle, I failed to add the following, which may / may not be relevant:

1) I tested it 4 times & it started immediately on every occasion.
2) To get it it to start though, I had to turn the key to stage 2 and then enter the code in to the sigma keypad. It would not start without doing this.
3) I had disconnected the thin (red/black) wire at the starter motor (and replaced it with my "made-up wire").
4) I reconnected the thin wire and the neg battery terminal and attempted to start with the key - no joy.
5) I have now put the vehicle battery on charge overnight and plan to return tomorrow AM to repeat the test a few more times.
6) Whilst I was there and before I did this procedure, I tried the jump lead from neg battery to engine lifting bracket - it didn't start and just heard the single click.

1. That sounds OK. No electrical or mechanical problems with starter motor assembly.
2. Suggests that Sigma unit is also interrupting the ignition services (A2), orange wire output of the ignition switch, but is not causing problems.
3. Yes that would make connection easier. Wire is only live with key in start position.
4. Thin wire is for solenoid. This confirms connection problem somewhere.
5. I expect it to be OK. I think that you could now start wire tracing.
6. As no improvement with jump lead, suggests no problem inside flag terminal.