Running problem
Discussion
I took the S3 out yesterday afternoon for a jaunt around the south with some other owners. I'd been driving for about 3 hours or so when the engine started to intermittently cut out, causing the car to kangeroo down the road. It got progressively worse, the engine being off far more than it was on until eventually it would die completely.
If the car was left for a few minutes, it would usually start up again and I could progress for few hundred yards before it became undrivable again.
I was forced to abandon the car in a pub car park :cry:. An RAC patrol, who by chance happened to be in the pub, had a look and suggested it might be running to lean due to a faulty sensor on the air intake. Just before it cut out, he could hear a sucking noise coming from the intake as if it was drawing too much air in.
Anyway, I returned to the car about 4 hours later and managed to drive it the 15 or so miles home without a problem.
Does anyone have any suggestions? The problem didn't seem to be speed or rev related, but did seem to be temperature related as when the engine cooled down a bit it would improve and I didn't have any problems in the evening when the ambient temperature was lowerr. The engine temperature was normal (both during the day and later in the evening when I drove it home), reading around about the 90 mark, but it was an exceptionally hot day yesterday, the hottest I've driven it in.
Any pointers would be greatly appreciated!
If the car was left for a few minutes, it would usually start up again and I could progress for few hundred yards before it became undrivable again.
I was forced to abandon the car in a pub car park :cry:. An RAC patrol, who by chance happened to be in the pub, had a look and suggested it might be running to lean due to a faulty sensor on the air intake. Just before it cut out, he could hear a sucking noise coming from the intake as if it was drawing too much air in.
Anyway, I returned to the car about 4 hours later and managed to drive it the 15 or so miles home without a problem.
Does anyone have any suggestions? The problem didn't seem to be speed or rev related, but did seem to be temperature related as when the engine cooled down a bit it would improve and I didn't have any problems in the evening when the ambient temperature was lowerr. The engine temperature was normal (both during the day and later in the evening when I drove it home), reading around about the 90 mark, but it was an exceptionally hot day yesterday, the hottest I've driven it in.
Any pointers would be greatly appreciated!
Hi Jon
Could be the coil?? But I don't think so as it is only around 6 months old. Take the plugs out and check the colour, see if they are sooting up or if they are going white and corroding. This would indicate a faulty mixture. Black Plugs indicate a too rich mixture and white too lean. Only as rough guide though. If they are one extreme then it would indicate a wrong mixture.
Could be the coil?? But I don't think so as it is only around 6 months old. Take the plugs out and check the colour, see if they are sooting up or if they are going white and corroding. This would indicate a faulty mixture. Black Plugs indicate a too rich mixture and white too lean. Only as rough guide though. If they are one extreme then it would indicate a wrong mixture.
Jon,
It didn't occur to me yesterday, but could the problem be due to fuel starvation cause by a vapor lock in the fuel tank?
There was no smell of excess fuel from your exhaust which points to a lack of fuel rather than an excess of fuel - which may be the case if you had an ignition problem.
Andrew.
It didn't occur to me yesterday, but could the problem be due to fuel starvation cause by a vapor lock in the fuel tank?
There was no smell of excess fuel from your exhaust which points to a lack of fuel rather than an excess of fuel - which may be the case if you had an ignition problem.
Andrew.
Andrew,
My Dad suggested that it might be a fuel problem too - fuel evaporation due to the heat of the engine combined with the midday sun beating down on the bonnet could have caused a vapour lock. It was certainly running as if I'd just run out of fuel! I've had a quick search of the forums and apparently you can buy lagging for the fuel rail so I might give that a go.
Thanks for the advice! Unfortunately it seems to be one of those intermittent problems that you can never recreate when you need to!
My Dad suggested that it might be a fuel problem too - fuel evaporation due to the heat of the engine combined with the midday sun beating down on the bonnet could have caused a vapour lock. It was certainly running as if I'd just run out of fuel! I've had a quick search of the forums and apparently you can buy lagging for the fuel rail so I might give that a go.
Thanks for the advice! Unfortunately it seems to be one of those intermittent problems that you can never recreate when you need to!
Agreed,open the cap and that should relieve the problem if thats what it was,though I rather doubt it.
The pressure is such when driving even at low speeds that I would be surprised is evaporation at the fuel rail was an explanation.
TP? but thay don't usually cure themselves again,unless it was the wiring getting too hot on top of the engine which might return to continuity once cooled down.Jiggle it about with the engine hot,that to all the front sensors and injectors.
Does sound to me as something electrical was sending a false signal to the ecu which changed the mixture to compensate and it didn't need changing.
Like Chris says, check the plugs whilst you check the electrics at the front end.
Also that legendary ignition plug under the dash...is that getting too hot?
Good luck.
The pressure is such when driving even at low speeds that I would be surprised is evaporation at the fuel rail was an explanation.
TP? but thay don't usually cure themselves again,unless it was the wiring getting too hot on top of the engine which might return to continuity once cooled down.Jiggle it about with the engine hot,that to all the front sensors and injectors.
Does sound to me as something electrical was sending a false signal to the ecu which changed the mixture to compensate and it didn't need changing.
Like Chris says, check the plugs whilst you check the electrics at the front end.
Also that legendary ignition plug under the dash...is that getting too hot?
Good luck.
Don't think it would be the TP, the car never ate TPs, and the one on there is less than 6 months old or so. Shouldn't think it is a fuel issue, unless the pump or filter is faulty, as most people know I drove the car every da in all kinds of weather and from what jon describes this weekend should be easy picking sfor it. Mind you thngs can change and it's worth exploring all avenues.
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