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Discussion Starter #1
Hi,

On Sunday our 2004 Automatic Scenic 2 1.6 vvt developed the not uncommon 'won't idle after starting' problem but there's something a bit odd going on.

1) After starting the engine (hot or cold) it idles low and then dies after about 10 seconds.

2) Hold the revs at 2k it has a slight misfire, drop it back to idle and a few seconds later it stalls.

3) Restart engine, repeat above but this time blip the throttle past about 4k. When the idle drops back it's (usually but not quite always) fine. Turn off the engine, immediately restart and the problem has returned but a quick blast of high revs sorts it out again. This seems crazy but I'm sure it's taking the revs beyond a certain point that fixes it.

Here's what I've tried:
- There's no dash warning and no OBD codes.
- I've changed cam sensor, cleaned crank sensor and cleaned throttle body - no change.
- removed and tested the dephaser solenoid which is fine and there's no rattles from dephaser pulley.
- OBD 'live data' readings for advance look fine (0 degrees at idle, 20 - 30 at higher revs, I presume this is what it is doing rather than what the ECU thinks it's doing?).
- Unplugging solenoid makes no difference apart from 'check ignition' warning.
- All coils are Beru, swapped each one out with another - no change.
- Temperature readings via OBD look good.

I'm at a bit of loss now. Does any of the above look familiar to anyone?

Thanks in advance,
James.
 

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You make no mention of Spark Plugs, what do they look like & have you changed them? For £10 that would be my first change.
 

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Discussion Starter #3
Hi Tim,

I'd thought about plugs but discounted them as the problem goes away completely after driving down the road (if you can pull away of course, being an auto) or after blipping the throttle. If it was a plug I'd expect it to idle badly for the whole journey, not just for the first minute or so?

I'll happily change them if they could be at fault?
 

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Hi Noel,

I wondered about temp sensors - maybe the ECU is in 'cold start mode' and overfueling etc. The OBD 'Live data' Engine Temperature looks about right, the inlet air temperature looked high (~50c) but google says that's just residual heat and normal until you're actually driving so I'm guessing both ok.

MAP - that's manifold air pressure? I'll have a look at the readings coming back from it.

It does seem like a few minutes after starting (or triggered by high revs) a condition is met that causes the ECU to change 'mode' or change some setting.

If it's helpful there is sometimes a fuel smell when it stalls, and when it does stall there's a big judder of the engine - no idea if anything can be read into that though.
 

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Discussion Starter #7
I've had another look at the car tonight. The MAP sensor looks ok - it reads about 40kPa at idle, rising to 70ish under a big load. Plugs are ok too.

I have had another look at the dephaser solenoid however and am 99% sure that that or something related is the culprit. I wrongly said before that disconnecting the solenoid made no difference but it does - the engine is running fine without it and consistently stalls when it's reconnected. I've found another post which described pretty much bang on what I have, including blipping the throttle to resolve it.

So next question - the solenoid is receiving 11v as soon as the engine starts. Is that normal? I suspect so but not sure. If it is, then how do I test the mechanical action of the solenoid beyond checking it moves when powered up (which it does)? I presume it must be advancing the dephaser prematurely so maybe an ecu fault rather than a mechanical one? Any suggestions gratefully accepted and tomorrow I'll run the car without the solenoid which I gather is perfectly safe.

Thanks all,
James.
 

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Hi did you manage to cure the fault as mine is doing exactly the same like yours runs fine with the solenoid disconnected
 
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