Ideas please. Renault Scenic 2002 16v petrol not starting.

[Agile]

This is a second car of the same model that I have recently bought.

Lower mileage and generally in good condition.

Two days ago it did not immediately start. I put that down to operating the starter too quickly after turning on the ignition. Started next time and ran fine for the journey.

But yesterday, even pausing when starting it totally refused to start. Turns over fast and no sign of any firing at all. Even with different accelerator position.

Had to leave it and use the old car. Today still the same.

For a previously always working fine car, what possibilities are there for it to totally refuse to fire up?

 

[Burnerman]

I guess this is a diesel vehicle, and I'd be looking at the crankshaft and camshaft position sensors - particularly the former.
Assuming the immobiliser is behaving ( lock the car with the key fob, open it and immediately try for a start) - the fuel supply is being closed down.
John

 

[DaveHerns]

Turning over fast and not firing doesn't sound good. How fast? Low compression/ cam belt slipped?

 

[Mottie]

A lot of Renaults suffer with water entering the fusebox and causing corrosion. Do you have access to a code reader? We had an old works Clio run-around that every now and then refused to start. We'd read the codes, find absolutely no fault but 'clear' the faults anyway. It would then start and run fine....until the next time! We never got to find out why.

 

[DaveHerns]

Don't Renaults suffer from the wires in the loom corroding away? Still this one is 15 years old and well beyond it's intended life. Years ago that would have made it a classic car!

 

[Mikefromlondon]

Don't know too much about diesels, a friend with a Merc, had just changed diesel filter on his and afterwards it refused to start, so i looked on web for him, things were pointing towards air trapped in the filter so filter needed priming manually. Soon after it started, may be a one way valve to stop diesel flowing back into the tank could cause such like problems?????

Glow plugs? timing issues etc like with the belt slipping covered above.

 

[DaveHerns]

I wouldn't have thought it was cold enough in the London area at the moment to have the glow plugs operate on start up.

 

[Agile]

Sorry, I totally forgot to say that they are both petrol cars.

Odd thing that a few days ago when it initially did not start, when it did it all ran fine.

Just in case it gives any ideas, I had borrowed the battery. But was OK for two days until now.

Does anyone know what could be blocking the emu from allowing it to start?

But there are no faults indicated on the control panel.

The weather is fairly warm and it is dry.

Usually I am pretty good with cars but in this case feel I just don't know where to start.

 

[Mottie]

Sounds like it could be the same as our old Clio - see my post #4 above. We never got to the bottom of that either!

 

[Burnerman]

Can you hear a buzz from the fuel pump, as the ignition is switched on?
Expose the fuse / relay panel, and wobble each relay in turn, listening for clicking.
John

 

[Mikefromlondon]

If it is petrol, then you can split diagnoses into two or three parts: (General diagnostics that applies to most petrol engines and is not Renault specific)
1, Ignition, this includes immobiliser problem, chip in the key (Transponder chip) may not be communicating with the ignition switch sensing collar, most cars would show some kind of indication indication (flashing light in dashboard) or fault code for immobiliser/alarm issue

Check for spark - pull HT lead and check for a strong spark at all 4 plugs if it uses individual spark modules on top of each plug, check for lose connectors to modules, some cars can even stop firing if one spark module is disconnected, get someone to crank engine, no spark can be immobiliser or electrical sensor failure, ignition/fuel pump relay, fuses etc. check connectors throughout especially for crankshaft angle sensor, cam sensor, these are key sensors in starting an engine, others like temp and pressure sensors are not a major issue.

2. Fuel system, Switch on Ignition, see if you can hear fuel pump whirring, you may need someone to do that whilst you try to hear the whirring noise near the fuel filler cap or fuel tank, or under the car. On switch on the pump should run briefly for a few seconds and stop if engine is not cranked.
Check if your engine has a facility to see if fuel injector rail has a test nipple for checking fuel pressure, Vauxhalls have one., otherwise check to see if you can diusconnect one of the fuel hoses with care and pull it out to see if there is pressure, fuel may squirt with force, if not hold the pipe steady and get someone to switch on ignition, for a very brief time like 1 or 2 seconds, does it squirt fuel?

If not issues can be sticking fuel pump, wiring or electrical issues to FP.

3. Other things can be the MAF flow sensor, that can stop a car from starting, but usually these sensors failing generate a fault code.

And of course as Motman said check for corrosion in fuse box, poor corroded connections.

 

[DaveHerns]

When was it last serviced? Mileage? Have a look at the spark plugs. Wet? Sooty? Get the fault codes read.

 

[Agile]

I tried it again yesterday.

Failed to start twice.

Not sure why but tried it a third time and it started immediately and so ran it for 20 min to recharge the battery.

Odd thing is it runs very well when it has started and at MOT a couple of weeks the emissions where pretty good/normal.


I did wonder about the fuel supply. But plenty in tank and its parked on a bit of a slope to the front.

Anyone know what kind of fuel pump and where it is? Never heard anything I thought was a fuel pump!

 

[Mikefromlondon]

google is your best friend, or join a Renault Forum, members owning similar cars would be able to help you better,

 

[Mottie]

The crank sensor (fitted to a bracket in a recess at the top of the bell housing) is a known fault on these too. Can you get it plugged into a diagnostic sensor?