I'd say the dephaser is broken. Common on the 1.6 VVT engine.

You're looking at getting the cambelt done too while the dephaser is being replaced.

Depending on age, Renault may help with costs here, but you need to ask first, not after the work is done.

 

Thanks for that

He's due a cambelt service. How much approx would you imagine it is for the cambelt service plus the fix

 

Assuming it's the VVti engine I would suspect a faulty dephaser pulley.

If it is the dephaser I would estimate repair costs at around £500 but it would be best to phone around for quotes.

 

Wow, this is gonna make him miserable lol

Thanks guys!

 

I think the dephaser is a Renault only part, so you can't get it cheaper elsewhere. It's about £160.

I paid £324 for a belt change at an independant, not including the water pump as that was deemed to be fine.

So, as noel says, it's going to be around £500.

The dephaser can be hobbled, so the rattle is silenced by the internal bits being fixed in place, there are threads on here about this. You still need to get it off to do that, so not really a cost saver unless you can do all that yourself and it's debatable whether it is a good thing to do.

 

The dephaser can be hobbled, so the rattle is silenced by the internal bits being fixed in place, there are threads on here about this. You still need to get it off to do that, so not really a cost saver unless you can do all that yourself and it's debatable whether it is a good thing to do.

The 1.6 dephaser pulley isn't the same design as the F4R & F4P dephaser pulleys. The 1.6 ones I've seen have 4 large chambers unlike the larger engines which have 8 chambers which makes them easier to do

 

Aaaaah I see so it can be fitted with a cambelt change at no extra labour cost? Just additional cost of the dephaser itself.

Thanks

 

Well, that depends on the garage.:d

 

I didn't know that RS, but I question the whole idea of messing with the dephaser. These cars don't even like the wind in the wrong direction, let alone having part of the engine hobbled.:d

 

Not all engines have VVT so based on this I make the assumption rightly or wrongly that it's of no detriment to an engine not to have it.

In the photos a 1.4 K4J / 1.6 K4M cylinder head form a 2003 1.4 Scenic and a 2.0 F4R cylinder head circa 1999 I belive. They both use exactly the same pulleys having the same part number. The 2.0 cylinder head is only very slightly wider and longer than the 1.4

I have a 1.4 Scenic as a run and it's pretty gutless, you have to keep the revs up and use the gearbox to keep it moving at a reasonable rate of knots so I wonder why VVT isn't used on the smaller engine which would benefit from a bit more oomph?

From what I read even after having a dephaser changed they can still eventually start to rattle again and IMO the benefit of it isn't noticable then why bother spending money on new dephaser ?

Though my experince is limited to the MK1 Phase 2 Scenic. Maybe on the MK2 Scenic like yours it is of greater benefit ?

I have recently bought another dead Scenic a 2001 2.0 Monaco on removing the engine cover I found the dephaser pulley was missing and the end of the inlet camshaft snapped off! I wonder if the cause of this was a badly rattling dephaser pulley?

In the photo the broken inlet cam shaft and at the side of it a non VVT 2.0 inlet cam shaft which has only 2 cross holes through it. The broken cam shaft would have been 6mm longer and have extra oil grooves in it which might mean it's not as strong?

 

You have to consider on VVTi engines that not only will the valve timing alter but also at the same time when the throttle is opened the ignition timing will also change.
I suspect the ECU mapping would be different on the VVTi engine. In other words the ignition timing advance or retard sequence may be different.

 

Hmm, is it possible for mapping to be corrupt? I'm just guessing, but in my ongoing fight to get my car running smoothly, I'll consider all options.
Assuming the mechanical advance is working, how would I know if the ignition timing sequence was matching it?
Would an ECU reset override it?
Would it show up any codes at diagnostics?
The car idles fine, starts fine, revs fine at standstill, it just runs bad.

 

I'm not suggesting the mapping is corrupt just that the mapping for the VVTi engine may be different to that of the non-VVTi variety.
If that was the case and the dephaser was removed then the mapping may not be compatible.
As the ignition timing is influenced by the map sensor particularly when the engine is under load I would think the mapping would need to be different on engines where the valve timing can be altered.

 

I didn't think that you suggesting that, but it made me think that if the mapping was not correct, for whatever reason, it could explain why all the mechanics that have looked at my car just scratch their heads, saying that no faults come up so it must be alright.

Regards the MAP sensor, I disconnected it the other day and the car went like a rocket, but still had slight hesitation as before. The cabin resonated more than usual too, on idle.

Still, proved that there is some power there somewhere.:d

I understand that MAP sensors have specific values that can be tested and measured to determine correct operation of the sensor.
No luck googling this though?

 

With VVT the inlet valve timing gets advanced so the valves open sooner than they would with static valve timing when the engine is set to TDC.

If the valves are opening sooner then I would have thought the injectors have to open sooner too, to deliver fuel sooner ? Otherwise whats the point of the valves opening earlier if no fuel is entering the cylinders?

I see, but what makes the injector fire? How does it know the valve is open?

 

WTF? The last few posts on this thread have gone. Whats happened?

 

Mr Lagdti has intervened trying to de-confuse things

I see, but what makes the injector fire? How does it know the valve is open?

The injectors don't fire they just deliver fuel on the induction stroke. The spark plugs ignite the mixture on the compression stroke. with static valve timing then the injectors will always open at the same time which is one of the functions of the TDC sensor I would imagine.

 

So, the fuel is drawn into the chamber by the vacuum?

Before that, is the fuel pumped to the injector rail and the pressure regulator makes sure it doesn't over supply it?

 

So, the fuel is drawn into the chamber by the vacuum?

The action of the piston going down the bore will create a vacuum and draw the fuel in

Before that, is the fuel pumped to the injector rail and the pressure regulator makes sure it doesn't over supply it?

The pressure in the fuel rail should remain fairly constant which the job of the pressure regulator as you say.

The supply of fuel to the cylinders is controlled by the injectors which need to have a constant stable supply of fuel to them. They deliver precise quantities of fuel I should think they will have a fuel flow rated in something like millilitres of fuel per second.


The quantity of fuel delivered is dependant on how long the injectors are left open. The O2 sensors also play their part by monitoring the oxygen levels in the exhaust so that the ECU can control the injectors accordingly

 

We're going to get told off for being in the wrong thread.

I'm looking for possible cause of my hesitation, the O2 sensors have not been checked, but would show up on a diagnostic I guess.

Another culprit could be the fuel pressure regulator, wonder how I can check that?

 

I've not had an electronic slapping for a while !:d

I would think both those things should show up on a diagnostic scan

 

In which case my car is in perfect health as nothing shows up on diagnostics.

 

And so is mine with its erratic/lumpy tickover..

 

Ain't technological progress great eh?

All in the name of alleged fuel efficiency and anti pollution requirements.

 

Aaah well at least it gives us something to moan about :d

 

The older I get, the more I find though.

 

THanks for everyones help on this, most useful

Well I rang Renault and they quoted £1000 + VAT for a cambelt + service + dephaser pulley.

I am guessing this is the usual main dealer rip off. Does anyone know any trust worthy garages or Renault specialists in the Stoke-on-Trent area that could possible offer me a better price?

Thanks for your help

 

I just had a cambelt, full kit, and water pump replaced on my sons 1999 scenic at Halfords autocentre (in Rayleigh. Essex) for £309.00 inc. vat

 

Hi. I had this problem with my 1.6 vvt modus. it was under 4 years old with a full service history and only 19k miles. I contacted Renault UK and they paid in FULL for everything to be replaced.
try these phone numbers: 0800 0723372 or
01923 895000. Good Luck.