Where's the spark gone?
Discussion
Morning all,
Last weekend’s drive resulted in a visit from the AA man. He managed to get my S3 sparking again, by wiggling the coil LT connectors, but I think that something more sinister might be the cause. Here’s what happened:
Quite difficult to start the car on Saturday morning – The first time this has happened, and needed two attempts. Thirty minutes into the drive, there was a large ‘cough’, followed by a complete cut out (luckily there was a lay by!). The car wouldn’t start again (although did turnover), and there was the smell of unburnt fuel, so I called the AA. The man diagnosed a lack of spark, and traced the issue to the LT wires coming from the coil. As I said, after wiggling these around, including the spade connectors, the car started again and we drove off. Throughout the weekend two more breakdowns occurred when up to temperature, which were fixed by ‘wiggling’ and leaving to cool for ten minutes.
I thought that the problem might be related to the ignition module – is this a common occurrence? The HT leads are fairly new, but the coil looks pretty original. Haven't checked the condition of the ig module yet.
Alex
Ps, thanks to the grey Tamora driver who beeped and waved!
Last weekend’s drive resulted in a visit from the AA man. He managed to get my S3 sparking again, by wiggling the coil LT connectors, but I think that something more sinister might be the cause. Here’s what happened:
Quite difficult to start the car on Saturday morning – The first time this has happened, and needed two attempts. Thirty minutes into the drive, there was a large ‘cough’, followed by a complete cut out (luckily there was a lay by!). The car wouldn’t start again (although did turnover), and there was the smell of unburnt fuel, so I called the AA. The man diagnosed a lack of spark, and traced the issue to the LT wires coming from the coil. As I said, after wiggling these around, including the spade connectors, the car started again and we drove off. Throughout the weekend two more breakdowns occurred when up to temperature, which were fixed by ‘wiggling’ and leaving to cool for ten minutes.
I thought that the problem might be related to the ignition module – is this a common occurrence? The HT leads are fairly new, but the coil looks pretty original. Haven't checked the condition of the ig module yet.
Alex
Ps, thanks to the grey Tamora driver who beeped and waved!
awep said:
I thought that the problem might be related to the ignition module
Could be but why not try the quick and easy fix first and sort out the coil connections?Coil could be "breaking down" (you mentioned 10 minute cool down), is it leaking are there any signs of oil around it?
Some people have moved the coil to get it away from being sat above all the engine heat.
The back of the ignition module has heat sink paste spread on it before being screwed onto the distributor, 25 years later this paste was more like a powder on mine. I wasn't having a problem but replaced it as a preventative measure...... clicky
Don't try to over complicate the issue. If it stops and wiggling the wires makes it go again, then, more than likely a break in the wire.
The "big cough" before stopping could also be a symptom of the same problem. If the spark is intermittent you can get unburnt fuel in the exhaust, when this ignites in the exhaust, "big cough".
As Mike said, sort those wire first then see if you still have issues.
Carl.
The "big cough" before stopping could also be a symptom of the same problem. If the spark is intermittent you can get unburnt fuel in the exhaust, when this ignites in the exhaust, "big cough".
As Mike said, sort those wire first then see if you still have issues.
Carl.
Edited by Ceejay73 on Tuesday 16th August 17:42
For intermittent problems like this I find that tally lights are a very useful way to see what's happening. In this case a small lamp connected to the coil +ve and placed where the driver can see it will tell you whether the coil is actually getting power. Do be careful not to shock yourself though - even the low tension side can get some significant voltages on it when the engine is running. I've lost count of the number of weird fuel pump problems I've tracked down like this.
I am going to the Revival, but in the newly acquired diseasel C-max daily. Purely for expediency and modesty when changing into period costume ( difficult in an S ). Look out for an eccentric fellow in mismatched tweeds covorting with the charladies .... 
Greymrj ( WWII Merchant Marine Chief Engineer Officer ) and family will also be attending.
Greymrj ( WWII Merchant Marine Chief Engineer Officer ) and family will also be attending.
awep said:
I'll take a look at replacing the LT wires - the car has to be ready for Goodwood on the 9th! Is anyone else going?
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