Saxo will not start

merlin617 · Post by **merlin617** » 09 Nov 2010, 15:13

Other half has a 1999 1.0 Saxo that intermitantly will not start after a run that includes getting stuck in traffic. Suspected overheating.

So far this has had a new head gasket, spark plugs and TDC sensor. A recent RAC call out put diag equipment on and said it was defo the engine temp sensor so changed that. The fan did cut in so I thought it must been the problem solved but its back again. Wondering if it could be the coil pack.

Any help please.

spider · Post by **spider** » 09 Nov 2010, 15:17

I was going to suggest coil pack.

The temp sensor if faulty will usually read higher (so it will cause a poor cold start) , if the signal is missing all together it will usually substitute a default mid range value (so you can drive like that but hot and cold starting will be not perfect, think of this as having a carb's choke about 1/4 the way out)

Be aware the sensor for the radiator fan is not the same as for the ECU (apart from some of the ultra rare models with A/C, not sold here)

Coil packs can break down intermittently, although I would half expect a misfire when hot in that case, substitution is the only really sensible test unfortunately.

merlin617 · Post by **merlin617** » 12 Dec 2010, 09:29

forgot to thank you Andy

spider · Post by **spider** » 12 Dec 2010, 10:58

You're welcome.

What was it in the end ? , was it the coil pack ?

falling-out-with-my-car · Post by **falling-out-with-my-car** » 14 Dec 2010, 12:54

there is a test that can be done for a coil pack breaking down but only if the car is able to run unfortunately.

using a piece of plastic 1.5 inch sink drain pipe like a telescope held on top of the coil pack rev the engine in the dark and look for flashes of light /sparks within the electronic coil pack apparently this is a sure sign of the coil breaking down.

we had a similar problem with a pug diesel a while ago and although there is no coil on a diesel the diagnosis we were told by peugeot was the map sensor, unfortunately the owner could be bothered to replace it and auctioned the car as it would start and run then stall and not start again whilst it was hot, once cooled it would run again but not perfectly if a bit juddery.

a long time ago I had a BX 1.4 I dont know if an old engine like this would give any clues in those days these engines had a coil with a chip on the side of the coil this engine had similar symptoms as your car I went to Lucas and bought a new ignition amplifier chip problem solved, with the old chip once hot the engine just wouldnt start again until it had cooled. it was also stalling comming off motorway sliproads and again wouldnt start until the engine had cooled. the chip came with a special paste that had to be used very sparingly, a bit like the kind of paste you seat a processor chip with in a computer.