Megane II 1.6VVT - Cutoff problem, drive-by-wire

[MaRaNtZ]

This is my first post here, sorry in advance for my weak english.

My megane is a 04' model, equipped with K4M 16v-VVT engine and uses a SAGEM S3000 ECU (euro-3).

My problem is the stability of the drive-by-wire throttle at low angles.

Every time the pedal is completely released (and the engine enter in cut-off mode) the car BUMPS a bit like there was a speed-bump on the road, the same occurs when i hit the throttle a little (exiting from cut-off mode).

It is simply sluggish, non-linear, with an irritating bump at low throttle angle (not just low rpm).

I can't get really used to, it is simply horrible drive handling and the car feels "nervous" even to passengers.

Does anyone experience the same ?

Also, when in lower gears, it appear that the clutch need to be used VEEERY smooth, otherwise the torque bounce back and forth until it stabilize to the desired level.

No, i've replaced almost anything except ECU.
Both coilpack and sparks replaced, without effect.
ECU resetted to default with small improvements.
Seem like a design fault of the injection controller.

I've tested other models and i experienced the same behaviour, just a bit less severe, including some throttle lag that any drive-by-wire system unfortunately include.

I've started a poll about this.

Really, an opinion on what could be the cause is really appreciated.

[darel]

This is my first post here, sorry in advance for my weak english.

Also, when in lower gears, it appear that the clutch need to be used VEEERY smooth, otherwise the torque bounce back and forth until it stabilize to the desired level.

Hi MaRaNtZ,
Your English is pretty good! Better than my Italian anyway...

I have the 2.0 Megane (F4R) with six gears, and I don't really notice the first problem you talk about, but the second one definitely, and it is really annoying. It doesn't only happen in lower gears either, if you rev really high in say second or third the next change up causes the car to bounce also. Maybe they got the gear ratios wrong..

Anyway I just learn to live with it..

[soterman]

I voted for the last one.

My throttle is working as gently as any other car I have driven, i.e. I do not experience the cut-off feeling that you describe when you lift your foot off the gas pedal.

I admit the clutch has a 'narrow' engaging point, but I must say I prefer it that way.

[MaRaNtZ]

I voted for the last one.

My throttle is working as gently as any other car I have driven, i.e. I do not experience the cut-off feeling that you describe when you lift your foot off the gas pedal.

I admit the clutch has a 'narrow' engaging point, but I must say I prefer it that way.

I suspect that 05' plate megII have considerably improved on engine management (euro4), mine is unfortunately an earlier 04', and this can definitely make differences. (how to push RT$ for an ECU upgrade??)

The cut-off bouncing effect is mostly noticeable in 4th gear, the shift does not move very much forward so i assume that the engine is firmly mounted.
That's why i believe could be an injection management problem and not a mechanical failure, but who knows... it is driving me nuts, i hope to fix it in the warranty timeframe or i'll have to resell this fancy dizzy car.

Last time i've shown this to the dealer he told me that it's a common problem and that i must get used to and accept this as a "normal" behaviour... weird!

[soterman]

A slight clarification... I ordered the car on Dec 2004, and it was delivered on Jan 2005. So it's a 2004 'tunerlist' Euro 3 car. Late 2004, but nontheless 2004.

Could it be that your bottom engine mount is failing? Get it checked at your dealer...

[omar]

Lol - you've managed to express the problem I've had with the car for the last 3 years better than I ever have! I've got used to it but other people really struggle to drive the car - does worry me that I'll struggle to sell it privately as a result.

There is definitely a lag on the throttle, as much as half a second I reckon. I think my foot co-ordination has adapted to it but I have noticed that if I'm tired or in traffic for a long time it does get very tiresome.

Dealers never found any faults despite querying it 3 or 4 times. Will be very interested to hear if you find out the cause.

[silencer51]

Omar, we can rule out the dephaser pulley in your case.

That leaves two things to check:

1)The throttle potentiometer (which is part of the throttle pedal assembly)

2)The electronic throttle body

I think candidate no. 1 is the culprit... This is one of the things that doesn't show up on a diagnostic check...

[omar]

Any idea how much the part and labour might cost? Would hope to get some sort of contribution out of RUK as only been out of warranty a month or so.

Thanks

[STEVIE]

Hi ive got a 1.4 and mine is the same make's you feel like a right tw*t when you have some one in with you.ive drove a lot of cars in my time ferrari's to robin reliants and iam an advanced driver and it still make's me feel like i cant drive

steve

[Mr T]

Hi I own a 2004 1.6 Cabriolet & have had the problem described from new but with clutch & throttle control have reduced it.
Took the car into Renualt dealer (2 years ago) was told it was a known characteristic & could not be cured.
My brother-in -law has the same problem with his megane 1.6 (now out of warranty)
A few weeks ago the car started to make a noise on startup, for a few seconds, back to dealer who booked it in for a dephasor.
Noise now gone but the big bonus is ! the original problem is now cured as well, the engine has no dead spot & pulls away very smoothly.
The work done according to the invoice
Replace Timing Belt
Remove Refit/Refit Camshaft Pulley
Basic Road Test
Pulley Dephasor
Distib Kit ME3
Fanbelt
Core Plug
Plug
If the dephasor was for the noise at startup which has only just happened it is possible the distibuter kit (or possiblythe dephasor) cured the original problem
Hope this helps

[Mick]

Very Interesting, Renault warranty fixed the dephaser pulley and solenoid on my 2004 megane 1.6 VVT but I still encounter a flat spot at 1800 RPM when engine is half cold so what's a Distib Kit ME3, [/b] Will this fix the Flat spot

[MaRaNtZ]

Very Interesting, Renault warranty fixed the dephaser pulley and solenoid on my 2004 megane 1.6 VVT but I still encounter a flat spot at 1800 RPM when engine is half cold so what's a Distib Kit ME3, [/b] Will this fix the Flat spot

Is the flat spot problem you are talking about related to the cutoff problem ?

I don't have any flat spot, except at initial 1th gear jumpstart, when i release the clutch a bit fast it seem often that the torque have an hole of some fraction of secs, then it return back ... it's like the engine is changing the controlling algorithm when exiting from idle, with a little hesitation. I don't know if this can be considered a flat spot or not, as it occurs only when starting from 0 speed.

[Mick]

Ok that sounds a bit different to what I experience, I'm just curious to find out what a

Distib Kit ME3 is (what components are in the Kit and it's function) .. does anyone in the forum know

[MaRaNtZ]

Anyone else having this cutoff problem ?
It's hard for me to believe that is a potentiometer problem,
but if the fault cannot be investigated using the clip, how to convince the dealer to replace the potentiometer ??

[walibe]

My problems have almost entirely disappeared since it went to renault and had the camshaft sesnor replaced? I dunno if anything else was done software wise.