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Discussion Starter #1
My Megane (2005 16v 1.6l) stalls at idle in couple of seconds after starting cold if I don't keep the rpm around 2000. I began investigating for the cause and found out that bad camshaft position sensor could cause this behaviour. But to my surprise the sensor's wires seem to be faulty. I checked the voltage on the 12V line and I got only 5mV when ignition power on and 1mV when off.

Is it possible to bypass the 12V supply line safely straigth from battery or something similar without destroying the ECU?


I know the right way would be to check the continuity but I have no idea where the cables go behind the engine.
 

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Technical Supremo, Platinum, I let the Dogs out
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one way to think about it is as a light bulb, you have the power going in and the earth coming out , if power goes in the light comes on, if not it remains dark, now think of this as a sensor you get the power going in and a return leg, a full circuit will make the light come on ( or sensor working) and no power no light ( or sensor not working) - so in essence you could run a 12vDC wire to the power side and you would have power to the sensor, but what also you have to think about is the return leg runs right next to the power leg on the loom, so there is a very high possibility that what is causing the problem on the power in line is also happening to the return line, your best bet is to trace the wires, find where they are damaged and repair them.
 

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I have had 2x camshaft sensors fail on 2 different 1.6 vvt's, both my cars idle fine..... but the throttle becomes like a off/on switch, to my mind there should NOT be Direct LIVE 12v from battery (more a controlled power from ecu) to a camshaft sensor as it ONLY sends a pulse with cam rotation so is a trigger wire as in open circuit / close circuit.



Have you had any fault codes read ?


Also its known that a faulty dephaser pulley can cause stalling upon a cold start, do you get a rattle when 1st started that goes away after a few seconds?
 

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Technical Supremo, Platinum, I let the Dogs out
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yes which is how I figured the sensor worked, it had a +12vDC supply down one leg, the sensor open and closed a circuit for the +12vDC to be sent down the signal wire. It would be a post ignition +12vDC as it would need the signal for starting, but if the wire is damaged and not giving the required voltage then there is a good chance the signal wire that runs along with it is damaged too
 

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Discussion Starter #5
Thanks! OK, I'll leave the bypass power connection for now and try looking for a faulty wiring :). Any idea where the wires run behind the engine so I could find the end point or joint?


Answers to your questions:



- I don't have the engine light on but I read with a cheap elm327-reader and got P0010 - "A" Camshaft Position Actuator Circuit (Bank 1)


- Haven't heard any rattling sounds though, few months back once for a few days during colder winter days there was weird muffled rattling sound which I could hear while driving but stopped by itself later on. Sounds didn't stop even though I drove pretty long trip, maybe the cold and wet weather was jamming something as it never came back again.



And some weird behaviours:


- Car has this weird intermittent vibration on idle, like 4 times a minute it makes a gentle shake that can be felt on the seat. Also if I keep the rpm high when I start the car, those vibrations are more powerful and happen more frequently.

- Car stays on idle nicely after I've driven few miles BUT sometimes flicks the lights when I press the clutch down and rpm does a small dip way under 800 rpm and comes back up to around 900.


That's pretty much all I've noticed.
 

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p0010 is for the VVT solenoid not the camshaft sensor - although closely linked - the VVT solenoid is near no.4 spark plug hole in cam cover (cambelt end) as no.1 spark plug is gearbox end (french dont ask why...) this is retained by 1x 10mm head bolt and has a 2 pin plug (electrical) you could remove it and clean the mesh carefully on end. Normally this should i believe put on the EML if faulty.


As for other problems could be several things spark plugs worn or gaps too large or idle control valve needs a clean but ignore these until you fix main problem or they become a constant vault.
 

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Discussion Starter #7
p0010 is for the VVT solenoid not the camshaft sensor - although closely linked - the VVT solenoid is near no.4 spark plug hole in cam cover (cambelt end) as no.1 spark plug is gearbox end (french dont ask why...) this is retained by 1x 10mm head bolt and has a 2 pin plug (electrical) you could remove it and clean the mesh carefully on end. Normally this should i believe puts on EML if faulty.


As for other problems could be several things spark plugs worn or gaps too large or idle control valve needs a clean but ignore these until you fix main problem or the become a constant vault.

This advice is pure perfection, thank you! I'll dig in to the VVT solenoid first and then also check the sparkplugs and idle control valve too.


Sorry for being a pain but I tried looking for the valve before but I didn't find it, any pointers where it might be located and what it looks like?
 

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its the thing in his hand
 

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Apt and to the point, thanks! I feel a little wiser now:smile2:

that may not be same as yours as your is a mk.2 meg not a mk.1 phase 2 - but there will be other youtube videos if you look
 

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Discussion Starter #15
I've got a bottle of CRC 5-56, would that be good for cleaning the solenoid? I saw someone use a brake cleaner and carburator cleaner too but don't have those at hand right now.
 

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Super fantastic Mod Technical Supremo Nice Guy
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WD40 would work, you want something to clean the mesh, and something that will allow oil to pass back through the mesh, So any solvent that wont melt or distort the seals will be ok...

Not a clue what CRC is, ... so cannot comment on that
 

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Discussion Starter #17
WD40 would work, you want something to clean the mesh, and something that will allow oil to pass back through the mesh, So any solvent that wont melt or distort the seals will be ok...

Not a clue what CRC is, ... so cannot comment on that

OK, I googled and found out that WD40 and CRC 5-56 are pretty much the same with same applications (rust removal, moisture removal, lubrication etc etc). They are just competing products and CRC is just more common here. Thanks, I'll have to give it a try!
 

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Discussion Starter #19
OK, took the vvt solenoid off today and gave it a good cleaning with the CRC (same as wd 40). I sprayed it, soaked it and let it dry and put back. So far didn't break anything :D. I tried to shake the solenoid with my hands and it gave a click -sound before and after cleaning but it was from an cold engine so I guess that doesn't give much info on how stuck it could be? I guess I can try clear the engine code P0010 for now to see if it did anything?


By the way, is it possible to safely dismantle the whole solenoid and get all the possible dirt off inside?
 
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