Electrical problem

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Ricky
Posts: 7
Joined: 6th July 2005 - 2:42pm

Electrical problem

Post by Ricky » 24th April 2018 - 10:50pm

Hi
I had trouble with starting my square, spark and fuel there, but no lights on the gauges. It was trying to turn over, but not firing. After spending time checking relays and connections (all good) I tapped the fuel gauge & the warning lights lit up and then next try the engine fired. What was the cause, ignition switch? Any ideas
Appreciate any clues
Cheers

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broady_6
Posts: 1747
Joined: 13th January 2009 - 9:55pm

Re: Electrical problem

Post by broady_6 » 25th April 2018 - 7:52am

have a look behind the dash and check all the brown wires are ok, (not crispy and/or melted) in turn disconnect and reconnect each one. It could just be bad earths. Check both ends, at the instruments and the earth posts behind the dash.
The sultan of swing

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937carrera
Posts: 741
Joined: 7th June 2013 - 11:54pm
Location: North Yorkshire

Re: Electrical problem

Post by 937carrera » 25th April 2018 - 7:25pm

Check the feed /connections to the ignition switch too - you could have been right.

Intermittent problems are a pain to diagnose :(
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon

Ricky
Posts: 7
Joined: 6th July 2005 - 2:42pm

Re: Electrical problem

Post by Ricky » 25th April 2018 - 8:50pm

Cheers for your help, all the wiring seems to be in good fettle behind the dash, so poss the ignition switch.. will recheck it

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Kai
Posts: 370
Joined: 3rd June 2007 - 12:40pm
Location: Surrey

Re: Electrical problem

Post by Kai » 26th April 2018 - 11:10pm

I’m no mechanic, but if you have spark and fuel, no reason apart from timing that your engine wouldn’t start. Perhaps if it was cold enough the electronic choke isn’t working. Compression even??

The fact that you have spark, confirms that the ignition is sending power to the coil. Now a weak spark is another thing....

The fact remains though, nothing up behind the dash board electronically is related to your engine electronics and running the engine, apart from the ignition switch which, sends power to your fuse box which directs power to your coil via one single wire.

Purchase a multimeter, start at the coil and trace the power supply back to the fuse box and confirm the connection.

Could also be the other end so check the condition of the gearbox earth.

Now I’m assuming your car is a manual gearbox with a carved engine.

Next time it doesn’t start, bypass the the ignition and fuse box by putting (fused of course ) 12v onto the coil and try starting it. In theory it’ll start as you already have confirmed a spark at the plug which would lead me to a compression test, checking valve clearances and vacumb leaks.

Who knows....

Best of luck.

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broady_6
Posts: 1747
Joined: 13th January 2009 - 9:55pm

Re: Electrical problem

Post by broady_6 » 27th April 2018 - 7:50am

Kai wrote:
26th April 2018 - 11:10pm
I’m no mechanic, but if you have spark and fuel, no reason apart from timing that your engine wouldn’t start. Perhaps if it was cold enough the electronic choke isn’t working. Compression even??

The fact that you have spark, confirms that the ignition is sending power to the coil. Now a weak spark is another thing....

The fact remains though, nothing up behind the dash board electronically is related to your engine electronics and running the engine, apart from the ignition switch which, sends power to your fuse box which directs power to your coil via one single wire.

Purchase a multimeter, start at the coil and trace the power supply back to the fuse box and confirm the connection.

Could also be the other end so check the condition of the gearbox earth.

Now I’m assuming your car is a manual gearbox with a carved engine.

Next time it doesn’t start, bypass the the ignition and fuse box by putting (fused of course ) 12v onto the coil and try starting it. In theory it’ll start as you already have confirmed a spark at the plug which would lead me to a compression test, checking valve clearances and vacumb leaks.

Who knows....

Best of luck.
Sorry im such a picky bugger. These cars have electrics and not electronics thankfully. :D Electronics refers to digital nonsense

You have got a good point regarding the ignition timing, also have you removed all the fuses and cleaned them and the terminals with some scotch bright. I cant see this helping the starting problem. But may help your gauge problem. And as kia described the power supply to the coil. trace that wire and at every join, make and break it a few times, also give the connections a clean.
The sultan of swing

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937carrera
Posts: 741
Joined: 7th June 2013 - 11:54pm
Location: North Yorkshire

Re: Electrical problem

Post by 937carrera » 27th April 2018 - 8:13am

If the car started and ran fine after the tap on the gauge, I wouldn't go messing with anything other than the wiring.

Very much sounds like a poor/intermittent connection problem. It might be worth measuring voltage at the battery, ignition switch and coil to see what sort of voltage drop you have. Use a good chassis earth when measuring.

If you have not got a multimeter, buy one or borrow one, you will use it.
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon

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