Independent Renault Forums banner
1 - 17 of 17 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
Hi, I’ve got a 2002 Renault scenic which has developed an intermittent starting fault. Engine turns over fine, plugs ok, ignition coils ok. Any ideas please? Thanks
 

·
Registered
Joined
·
584 Posts
Hello
I wonder if you could give some more information to help diagnosis.
When you say intermittent, how often, and how many times do you need to try it to get it to fire, that sort of thing.
I assume it's a petrol model as you've mentioned plugs and coils.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #3 ·
Hi, thanks for responding. Typically it’s fine for a few days and starts first time. Engine always turns over nicely. Then for no reason it just won’t start. Usually I leave it a few days and it starts. I have bump started it once when it wouldn’t start normally. Currently in the drive with a load for the tip refusing to start. Not sure what else to say. I do wonder if there’s a problem with the fuel supply although when this happened a few years ago it turned out to be a fuse but I can see that the major ones in the engine compartment are all good. Happy to answer and questions if you’ve got any ideas. Thanks
 

·
Registered
Joined
·
584 Posts
Ok, thanks for the information.
My opinion on the most likely causes, in no particular order:-
.. Damp in the electrics
.. Fuel pump electrics problem
.. Crankshaft sensor dirty, or on the way out.
(It could be lots of other things too - any codes in the OBD? And does the EML go out?)
Very hard to be more specific from a distance, I'm sure you understand. Your possibility of the fuel supply problem could well be in there. A fuse gone would mean it would never start until the fuse was replaced, but it could be a dodgy connection to the fuel pump, or water in the fuse box.
Crank sensor is worth a try if you can do it yourself, so no labour charge. Cleaning it is free, and a new one isn't too expensive, I did one on our Clio 1.6.
Which engine do you have?
If you have just tried starting it then it's a good idea to take out the spark plugs and see if they smell of petrol. If they do then the fuel supply is good, but the spark isn't.
If there's no fuel on the plugs then the fuel isn't getting through.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #5 ·
Ok, thanks for the information.
My opinion on the most likely causes, in no particular order:-
.. Damp in the electrics
.. Fuel pump electrics problem
.. Crankshaft sensor dirty, or on the way out.
(It could be lots of other things too - any codes in the OBD? And does the EML go out?)
Very hard to be more specific from a distance, I'm sure you understand. Your possibility of the fuel supply problem could well be in there. A fuse gone would mean it would never start until the fuse was replaced, but it could be a dodgy connection to the fuel pump, or water in the fuse box.
Crank sensor is worth a try if you can do it yourself, so no labour charge. Cleaning it is free, and a new one isn't too expensive, I did one on our Clio 1.6.
Which engine do you have?
If you have just tried starting it then it's a good idea to take out the spark plugs and see if they smell of petrol. If they do then the fuel supply is good, but the spark isn't.
If there's no fuel on the plugs then the fuel isn't getting through.
Thanks for that. It’s a 1.6. I’ll take the plugs out as a start and see if petrol is getting through and take it from there. Much appreciated.
 

·
Super Moderator Technical Supremo Platinum Member
Joined
·
22,330 Posts
What's the immobilisr light doing when it refuses to start?
Tried spare key when wont start?
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #8 ·
Thanks, I’ll try that when I get home tomorrow
Hi, apologies for delay in responding. Immobiliser light goes out with both keys. Blooming thing started yesterday and today so I’m thinking damp might be the problem. What do you think?
 

·
Registered
Joined
·
584 Posts
Hi, apologies for delay in responding. Immobiliser light goes out with both keys. Blooming thing started yesterday and today so I’m thinking damp might be the problem. What do you think?
Damp is a common problem with Renaults. The issue often is working out where the damp is!
Next time it won't go it may be worth pulling out the coils and plugs and seeing if they are damp.
It can also be the wiring in various water-prone bits.
But I'd also check the crank sensor on a car of that age, if it hasn't had a new one yet.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #10 ·
Damp is a common problem with Renaults. The issue often is working out where the damp is!
Next time it won't go it may be worth pulling out the coils and plugs and seeing if they are damp.
It can also be the wiring in various water-prone bits.
But I'd also check the crank sensor on a car of that age, if it hasn't had a new one yet.
Thanks, will do
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #11 ·
Damp is a common problem with Renaults. The issue often is working out where the damp is!
Next time it won't go it may be worth pulling out the coils and plugs and seeing if they are damp.
It can also be the wiring in various water-prone bits.
But I'd also check the crank sensor on a car of that age, if it hasn't had a new one yet.
Thanks I’ll do that. Much appreciated. Seems to be starting ok now it’s stopped raining but I need to get to bottom of it. Thanks again.
 

·
Registered
Joined
·
602 Posts
You can use an old spark plug, connect it to any of the coils, lean it against car body and try to start.
If there is spark on the plug and the engine does not start, it means that you are not getting fuel to the engine.

Most common problem is crank sensor. Crystal inside it cracks and you sometimes have loss a of contact, possibly worse when it's raining. When there is no contact, engine can be cranking but the computer does not "see" that the engine is turning (dead crank sensor does not send any signals) and computer does not inject any fuel into the engine.
Crank sensor is cheap, it is located on the clutch housing screwed by only one bolt, you can change it yourself. Connector of, new sensor, connector on, no need for anything else.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #13 ·
You can use an old spark plug, connect it to any of the coils, lean it against car body and try to start.
If there is spark on the plug and the engine does not start, it means that you are not getting fuel to the engine.

Most common problem is crank sensor. Crystal inside it cracks and you sometimes have loss a of contact, possibly worse when it's raining. When there is no contact, engine can be cranking but the computer does not "see" that the engine is turning (dead crank sensor does not send any signals) and computer does not inject any fuel into the engine.
Crank sensor is cheap, it is located on the clutch housing screwed by only one bolt, you can change it yourself. Connector of, new sensor, connector on, no need for anything else.
Thanks for that. I’ll change it as you suggest.
 

·
Premium Member
Grand Scenic 1.6 2007
Joined
·
5,604 Posts
Before buying anything I would get in at the wiper scuttle drains and make sure they are clear.
I shove a garden hose down the drain and let fly looking for the runoff at the back of the wheel arches.
Leaves and stuff collects there and if the water is held up it has lots of time to find ways to mess with electrics in the days after rain or a carwash.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #15 ·
Before buying anything I would get in at the wiper scuttle drains and make sure they are clear.
I shove a garden hose down the drain and let fly looking for the runoff at the back of the wheel arches.
Leaves and stuff collects there and if the water is held up it has lots of time to find ways to mess with electrics in the days after rain or a carwash.
I’ll check that but did it a while ago. Thanks
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #16 ·
Thanks for that. I’ll change it as you suggest.
Ok, thanks for the information.
My opinion on the most likely causes, in no particular order:-
.. Damp in the electrics
.. Fuel pump electrics problem
.. Crankshaft sensor dirty, or on the way out.
(It could be lots of other things too - any codes in the OBD? And does the EML go out?)
Very hard to be more specific from a distance, I'm sure you understand. Your possibility of the fuel supply problem could well be in there. A fuse gone would mean it would never start until the fuse was replaced, but it could be a dodgy connection to the fuel pump, or water in the fuse box.
Crank sensor is worth a try if you can do it yourself, so no labour charge. Cleaning it is free, and a new one isn't too expensive, I did one on our Clio 1.6.
Which engine do you have?
If you have just tried starting it then it's a good idea to take out the spark plugs and see if they smell of petrol. If they do then the fuel supply is good, but the spark isn't.
If there's no fuel on the plugs then the fuel isn't getting through.
Thanks for your help. It was the crank sensor. All sorted now. Thanks again.
 
1 - 17 of 17 Posts
Top