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Clio Engine Turns But Wont Fire - Brummig
I have a B-reg Renault Clio 1.2 Authentique, 19k miles. Normally I turn the ignition key to the point where the dash lights come on, wait for most of them to go out, turn the key another notch, and the engine fires almost instantly. Sometimes when I turn the key the extra notch the engine just turns and turns but wont fire. If I'm lucky then turning the ignition off and repeating the starting procedure will cause the engine to fire normally. Sometimes I have to try this several times and eventually the car will start as soon as I turn the key that extra notch. If I'm unlucky (which has happened about four times since I bought the car), the engine simply will not fire and I have to find alternative transport. However, if I then try the car an hour or two later, then it will start immediately as if nothing had ever happened. Cranking the engine continuously does not get the engine started - I have to turn the ignition off and try again. I've tried both keys, pressing the blip with the key in the ignition to resync the immobiliser, and locking an unlocking the doors, with no effect. It makes no difference if the engine is hot or cold.

My first thought was the immobiliser, but (a) the big round red dash light goes out every time as normal (it flashes rapidly if the key isn't recognised) and (b) the immobiliser wont allow the engine to turn when immobilised (I've checked). However, once the car starts there are no running problems at all, so it must be something that only affects starting.

The garage can't find anything. Anyone got any ideas?
Clio Engine Turns But Wont Fire - mfarrow
How old is this B-reg clio exactly? 1984??
Clio Engine Turns But Wont Fire - Peter D
B reg aagh that will be a private plate will it or is this a 98 model, mind tou with 19k on the closk it isn't going very far. Firstly let me ask, when it does this and you eventually get it to start does it start without coughing and sluttering and not smarll of excess fuel. If so then the ointers are. Immobiliser, i.e try the spare key, remove the key and turn it though 180 degrees and try it again, fuel pump relay or fuel pump not starting i.e lean out of the car and turn the igniton on you should here the pump whine up then stop its only quite so listen. Then next time it fails to sart leave the car 5mins then lean out listen and turn the ignition on, if no whine then suspect fuel pump, relay or fuse. Now if the pump is working then you need to check for a spark by removing one of the leads and pushing in a peice of wire and placing it within 3 mm of an earth point like the head and cranking the car at the same time as you can see the spark ( you may need help with this one.) Now if no spare but you heard the pump then the pointer is the flywheel sensor. This relative cheap part £17 or so can often do what you describe. Some times you can bump start the car and it is fine but it will not start on the starter, this is due to the speed the flywheel is doing. Remember if it does not start you need to get back to you drive. Also when cranking the car get someone to smell the exhaust to see if they can detect quite strong pertol fumes. Try these and come back with more info. Regards Peter
Clio Engine Turns But Wont Fire - Peter D
Forgot, I have had one of these with a fauly ignition switch and in the start mode there was no power to the management system but was when you stopped cranking, this was proven by bumpstarting the car when it was in the no start mode. Regards Peter
Clio Engine Turns But Wont Fire - Brummig
Apologies for the brain-dead "B-reg" - of course this is pretty meaningless now. I should have said "April 2002".

There's no coughing and spluttering once it does start, it just runs normally (and indeed starts as if I hadn't just spent the last few minutes trying and retrying), and I haven't noticed a strong smell of petrol (I did check for this). The fuel pump appears to run up, however (there's a "wonnnnng" from the engine compartment). I would have expected the engine to flood and the engine compartment to stink of petrol, but it doesn't seem to. Is there a clue there? Checking the exhaust is tricky since the problem would need to occur when I have someone with me, but if that happens I'll report back. Similarly with the spark plug suggestion. The flywheel sensor and ECU power sound like prime candidates given what you say - thanks very much.
Clio Engine Turns But Wont Fire - elekie&a/c doctor
Intermittent starting on most Renault models can be a fault with the flywheel sensor,but can also be a problem with the 2- pin connector that plugs into it.The metal pins in this plug have a habit of "opening up " & causing a bad connection,especially when the engine is cranking & thus moving more.Suggest get pins tightened up & retest.
Clio Engine Turns But Wont Fire - Tim Selwyn
Did you find out what was wrong in the end?

Girlfriend has exact same problem...

Thanks!
Clio Engine Turns But Wont Fire - Dynamic Dave
Did you find out what was wrong in the end?


See my reply to your other post.

www.honestjohn.co.uk/forum/post/index.htm?t=33035
Clio Engine Turns But Wont Fire - Brummig
By a weird coincidence I just happened to be looking this up again two days after new posts on it! Apologies for not posting the results, but the very nature of the problem meant I couldn't post the result quickly.

The answer is yes and no. The car was under warranty, so I just printed out this thread and asked the garage to replace the crank shaft sensor. So far all has been OK, but I've no idea if it it was a connector fault, a sensor fault, or a sensor which was not mounted correctly. However, it looks easy to replace and I understand it is a relatively cheap component, so it's worth trying. Moreover, although I don't know what technology this sensor uses, I do know what was used when I used to work in the automotive business. In the case of that technology the output voltage is proportional to speed (though it is frequency that is measured), so a dicky sensor may well work perfectly as soon as the engine starts and there is sufficient voltage to allow the ECU to measure its frequency.