Rado77 said:

Have you also checked main relay? By some reason main relay still gets signal to run engine (ignition and fuel pump). I dont know dependency with opening doors, but main relay is main thing to check, directly atfer key housing

Click to expand...

Hi,

When you say the "main relay", exactly which relay are you referring to?

Thanks,

Anthony

I think it should be in engine fuses box location. There's relay for fuel pump for example (black cubic thing...) and there are also some similar "cubes". On the bottom side of fuses box cover should be some fuses description (but on mine isn't :-( )

What would happen if you turn the key off and let the engine run for a while ? Would it eventually "die" by lack of fuel or not ?

BRs, Bernie

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Rado77 said:

I think it should be in engine fuses box location. There's relay for fuel pump for example (black cubic thing...) and there are also some similar "cubes". On the bottom side of fuses box cover should be some fuses description (but on mine isn't :-( )

Click to expand...

Ok I tested the following like-for-like relays:

(1) Fuel Pump relay was swapped with the Horn Relay.
(2) Engine Control relay was swapped with the Front Electric Window relay.
(3) Ignition Main Circuits relay was swapped with the Starter Motor relay.

It made no difference, symptoms are the same.

Bernievarian said:

What would happen if you turn the key off and let the engine run for a while ? Would it eventually "die" by lack of fuel or not ?

BRs, Bernie

Click to expand...

The engine continues to run on for a short while before cutting out. It can be anything from 10 to 60 seconds. The exception to this is when either front door is opened; this immediately causes the engine to shutdown.

Nice problem! I really like it Sorry.... :-( Maybe you can consider this behavior as "feature" and not a bug...? Imagine - I stop the car near my house, turn off key and remove it, and engine stops (and lights go off) when I open doors - thats perfect!!! :slayer:

OK so this went on the back burner thanks to Covid-19 but I'm back on the case.

So to recap, with all the doors closed if I turn off the ignition the instrument cluster, lights, radio, etc. switch off but the engine runs on until I open either front door. If either front door happens to be open when the the ignition is turned off, the engine stops as normal. Door electricals such as electric windows and speakers operate as normal.

I disconnected the front door wiring connectors from the A-pillars and, hey presto, the problem disappears. The engine no longer runs on, either with the doors open or closed. As soon as I reconnect the door wiring connectors, the problem reappears. So there seems to be an electrical problem whereby the door electrics affects the ignition's ability to turn off the engine.

I examined the wiring in the concertina hoses in each door. There were no broken wires on either side (which didn't surprise me as the electric windows and speakers function as expected). However, on the drivers side there were some nicks in the cable sleeves. As the wires themselves were not broken the best I could do was tape each individual cable to ensure no wire was exposed. I then re-tested but the problem persists.

I'm going to remove the door cards and perform a more thorough examination of the wiring looms across the circuit. In the meantime can anyone shed any light on what possible connection there could be with the wiring in the doors and the ignition? Could there be a short circuit that feeds back to the ignition and affects its ability to turn off the engine? Could other electrical components in the doors be culpable or should I focus on wiring? Are there further tests that I could conduct over and beyond examining the loom?

Thanks in advance.

Consider taking it to a garage. Good luck.

When you open a door with ign off it cuts out the window winder that allows
you to close the drivers window just after you switch off maybe there is some connection
to your problem there, I think there is also a timer that does the same without opening
the door, if there is a timer try switching it off and let it tick over see what happens when
the timer times out.

Just notice this is a old thread.

eeeno said:

Consider taking it to a garage. Good luck.

Click to expand...

Thank you for your wise words. The car belongs to a 77-year-old lady who, thanks to Covid-19, has been isolating for a year and a half. She can't afford a garage so I'm trying to fix it for her so she can have her freedom back.

RalphM said:

When you open a door with ign off it cuts out the window winder that allows
you to close the drivers window just after you switch off maybe there is some connection
to your problem there, I think there is also a timer that does the same without opening
the door, if there is a timer try switching it off and let it tick over see what happens when
the timer times out.

Just notice this is a old thread.

Click to expand...

Thanks, that's a good shout.

The strange thing is with the door wiring disconnected, the engine switches on and off as normal. Reconnecting the door wiring introduces the issues so it appears that door electricals are interfering with ignition.

Bernievarian said:

Both front and left front doors are interconnected (windows lifters) so I wouldn't be surprised an issue on one of them would reflect on the other...

This being said, I can hardly think about any relation between door's status and ignition's one. But lots of things can happen with electronic devices and it's well known that they are quite sensitive to noise and parasistic currents (bad earthing). So ONCE you will have discovered the root cause, we WILL have a rational explanation of what happened, but before you do it it's almost impossible to tell what's wrong ...

Hope I had better answer, cheers, Bernie

Click to expand...

Hi Bernie, I was wondering whether you could lend some wisdom to the matter.

I've established a connection between door electricals and ignition. When the door wiring is disconnected, the engine switches on and off as normal. Reconnecting the door wiring introduces engine run-on when ignition is turned off. I checked the door looms in the concertina hoses and no broken wires.

Check any earths on the door wiring if it as a bad
earth maybe it is finding a earth back through the
ignition.

Sometimes it takes courage to just give up. The problem's been there for two years without solution.

It's just a matter of taking a multimeter and measuring the continuity of each wire from the door connector to the BCM connector. If there is high resistance values or open circuit then that's a suspect number one. So far you've been able to isolate the issue to the door wiring. Great! Just continue. The problem as previously suggested may be the wiring or the bcm itself. Multiecuscan is able to scan the can bus for errors. :idea:

eeeno said:

Sometimes it takes courage to just give up. The problem's been there for two years without solution.

It's just a matter of taking a multimeter and measuring the continuity of each wire from the door connector to the BCM connector. If there is high resistance values or open circuit then that's a suspect number one. So far you've been able to isolate the issue to the door wiring. Great! Just continue. The problem as previously suggested may be the wiring or the bcm itself. Multiecuscan is able to scan the can bus for errors. :idea:

Click to expand...

Don't be fooled by the age of the thread. This is the first time I've looked at the car since 2019. Thanks to the pandemic, the owner began self-isolating in January 2020 and the car was locked away in her garage until this week. These are strange times we're living in so normal logic doesn't apply! I'm trying to do a good thing for a vulnerable pensioner on a budget so any positive assistance or advice is gratefully received.

So to be clear, you're suggesting that I measure continuity of the wires that run from the A-pillar to the BCM? Do I have to test both sides?

RalphM said:

Check any earths on the door wiring if it as a bad
earth maybe it is finding a earth back through the
ignition.

Click to expand...

Thanks. I'll remove the door cards and give that a shot.

The multimeter is a must-have tool when troubleshooting electronics. The wires may appear to be fine upon visual inspection and still have a problem.

Google knows everything on this. But basically I'd just disconnect both wiring ends and measure the resistance of each pin on both ends at the same time. High resistance means a short-circuit on that wire. You should be able to find wiring diagram online for this.

RalphM said:

Check any earths on the door wiring if it as a bad
earth maybe it is finding a earth back through the
ignition.

Click to expand...

OK, I stripped the door cards on the front doors and tested the ignition after disconnecting one component at a time (Tweeter, mid-range speaker, electric window switches, electric window motor). No difference, the problem persists. Indeed, disconnecting all door components on both sides makes no difference. It's only when you disconnect the main connector from the A-pillar that the ignition starts behaving normally.

I checked the wires in the concertina hoses and in both doors and there was no obvious visual signs of degradation. Same with wiring under the dashboard. All earths are present and correct. Time to get the multi-meter out.

eeeno said:

The multimeter is a must-have tool when troubleshooting electronics. The wires may appear to be fine upon visual inspection and still have a problem.

Google knows everything on this. But basically I'd just disconnect both wiring ends and measure the resistance of each pin on both ends at the same time. High resistance means a short-circuit on that wire. You should be able to find wiring diagram online for this.

Click to expand...

Yep, from what I can see visually the wires look ok (albeit some looms are difficult to check). Time to get the multi-meter out. Given I only have one multi-meter, how would I go about testing each pin on both ends at the same time?

There is a post on here with the same problem it was water getting in the fuse box,
maybe it's worth having a good look there for any damp corrosion and so on.

https://www.fiatforum.com/grande-punto/299503-engine-wont-turn-off-wet-engine.html

https://www.fiatforum.com/grande-punto/323880-grande-punto-wont-turn-off-key.html