Thanks DD and Adam for the input. My son has taken the car to a local independent chap who is pretty good from past experience. The CTS seems to be working OK - he says it has the right resistance (?). What appears to be happening is that the stepper motor (Idle control motor?) may not be working as required. Whether this is a problem with the motor or with the signal from the computer to the motor is a moot point. I gather that the stepper motor is not cheap (£130?) so replacing that may be an expensive way of finding out that there is nothing wrong with the old one. It seems to me that the solution may be to take the car to a main Renault dealer (those last 3 words were difficult to type!!) for a diagnostic check. Haynes says "no meaningful testing is possible on the idle speed motor".
I have used my usual technique for mending these things and given the piston on the stepper motor a good spray with WD40!!
Don't know if you can add any other help to what you have already contributed. Thanks for pointing us in the right direction - I've learnt some new terms - CTS, stepper motor etc! Would you still replace the CTS or is the resistance a goood indicator that it is working correctly?
PhilW
PhilW
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Hi Phil,
I have had several where the CTS resistance, checked at several points through the temp range, has appeared OK, but replacement has effected a cure, so at £12.18 + p&p, + VAT from Webcon (Southern Carbs & Injection 020 8540 2723) I replace the sensor at first report of starting problems.
The stepper motor can give problems, but would NOT usually account for the engine dying when you try to accelerate. If you replace the CTS and it is still the same my next port of call would be the MAP (inlet vacuum) Sensor function, looking at output voltage against applied vacuum.
Regards, Adam
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Adam,
Thanks again for excellent advice. As you say, at that price it is worth a try - it does eliminate one potential source of the problem.
Much appreciate the time you have spent replying. I will keep you informed. Don't suppose you are located anywhere in the Midlands or West Yorks are you?
Phil
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Sorry Phil, a West Sussex boy me !!
If you want a local independent expert to look at it I suggest you trawl Yellow Pages under Car Engine Tuning or Engine Tuning, but have to say that degrees of expertise do vary, as in any trade. Try asking friends and colleagues if they have used anyone they would recommend.
Do keep us posted !
Regards, Adam
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Dear Adam and All,
Sorry for the delay in up-dating you on this problem but with my son being in the U.S.A. and due back in 10 days I took the Clio to a Renault bloke (independent but experienced ex-Renault mechanic with computer analysis thingy who I do trust!). He reckons that the CTS is OK but there is a problem with the sensors in the carburettor body. He also says that these sensors are not made separately but require the replacement of the whole carb. Renault apparently charge £600 (yes £600 for this body - cheaper to replace whole car???) and has suggested that I try for a second - hand/reconditioned one on the internet or somewhere and he will fit it.
Three questions
1) Is his diagnosis likely to be correct? (I realise that without testing the car it is difficult to say - but does it sound reasonable/is it a likely fault/does this happen to Clios?)
2) Anyone know of a reliable source for a carb. body that is MUCH cheaper
3) Am I likely to find a good one at the scrappies??
Thanks in advance for any advice - it's likely to be my wallet rather than my son's which feels the pinch!!
PhilW
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Hi Phil.
As I have said before, I have seen several CTS that check out OK when resistance is checked through temp range, but somewhere there is a \"glitch\" that causes a problem, and replacing solves the problem. Obviously it MAY not be the problem, but at the prices mentioned, and bearing in mind that I personally have replaced at least a dozen over the years, and NEVER replaced the throttle body on this engine, I would always go for the CTS first.
FIRST, CHEAPEST, EASIEST !!
Incidentally, did this chap call it a carburettor ? If so I begin to doubt his experise, as this is a throttle body, NOT a carburettor.
Regards again, Adam
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Thanks again Adam - cause for thought there. I think I will follow your advice this weekend. Haven't had much time recently what with work, dark, cold evenings and lack of a warm, dry garage!
I'm sure he said "carburettor" body but then again maybe it's me - ain't had much experience of either those or throttle bodies for a long time!
I appreciate your advice. Will keep you informed
PhilW
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OOPS ! A throttle body it definitely IS, but \"single point\" just crept in there somewhere - I think the car inquestion is multi point, but it makes no difference to advice given !!
[I removed your \"single point\" error to avoid confusion. M.]
Regards, Adam
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Adam, I totally agree - change the CTS. I have looked at a few of these, and it seems that Renault use inferior antifreeze, which causes the business end of the CTS to corrode. Although the thermistor element still checks out OK, the circuit now leaks (electrically) to earth. I have been told that this can damage the ECU, but have not experienced this. It certainly causes running difficulties. Replace CTS and flush cooling system, filling with PSA 5 year antifreeze (Procor 3000).
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Thanks chaps,
Will do as you suggest ( but give me a couple of days more!)
Actually, having bought a Haynes manual, i know know where the CTS is located and I think you are right anyway - it is a single point ingection system, on a 1390 cc (EJ7) engine, and I also think that "my man" also knows that since he mentioned the stepper motor and the potentiometer which the carburettor model doesn't have(?). Perhaps he said carburettor because I'm an old git who wouldn't understand throttle bodies (he's right!). In a couple of days I will post you as to whether the replacement of the CTS works (and whether I need further advice on stepper motors and potentiometers!!)
Thanks again.
Phil
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Adam,
Well done, Your advice to Phil, unambiguous, considered and helpful.
My well cared for but ageing Astra SRI has also experienced temperature sensor problems, primarily the result of connector oxidation in the socket.
I live in West Sussex, North of Chichester. Do you trade in this area?
Regards,
Julian Lindley
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Adam,
Brilliant! Have finally got off my lazy backside, been to Renault and bought a CTS (£22.50 inc vat) and fitted it (about half hour after taking off various hoses, dizzy cap etc to ease access). Apprehensively turned the key and hey presto it sprang into life on the first turn, smooth tickover and pick up even when cold!!
Really appreciate your advice and I make it that I owe you about 300 (virtual?) pints!!
Thanks again,
PhilW
P.S. Thanks also to 659FBE for input
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Phil, Excellent news. Remember my comments about the antifreeze, and that this site is "infested" with people having problems with Renault heater matrices. I believe there is a link, and that Renault fit the same lousy Valeo components that PSA use. The survival rate in PSA applications is higher because they have the good sense to specify the very best antifreeze. Renault are too mean.
Bon voyage.
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659,
Will do.
thanks for your help,
PhilW
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Just bought 2000W Clio from small friendly Renault dealer. Asked him why Renault didn't specify coolant changes in Clios (or at least didn't a few years ago). He said no problem - modern coolant lasts for years. Better not to believe this, I think.
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Phil,
Glad to hear the good news - AT LAST !! Seriously, I was quietly confident all along, but the proof of the pudding is in the eating. Happy to hold the pints in credit until you visit this part of the country !
Julian,
I am based in Worthing, and quite honestly Chichester is about as far as it is economical for me to travel for work, but if you need some help sometime we could always arrange a rendezvous soemwhere halfway. For contact numbers see "www.uktuneup.co.uk"
Regards, Adam.
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Hi
I know I've posted about my problem seperately, but i was wondering if these cercumstances could be applicable to my 106 (K with Bosch monopoint injection). I was always a little scepticle about the garages diagnosis of it being the pot. track that was faulty when it stalls just as it's taken off idle with the engine warm and just started; but is fine after a few minutes and when the engine's started cold.
I might be clutching at straws here, but could it be the temp. sensor as with this chaps clio, being as the occurance of my problem is dependant on engine temperature?
cheers
M Farrow
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Certainly a possibility, although on the 106 I would also check the vacuum pipe from the inlet manifold to the MAP sensor - this suffers both from perishing at the manifold end (but this would give problems all the time) and can also get internally fould with oily slidge. When warm this thins out and vacuum response is quick, but cold it delays the vacuum signal to the sensor.
Regards, Adam
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Wotcher Adam,
I realise I'm replying to a pretty old series of messages here, but I just wanted to thank you for the advice you gave another guy on his Clio starting problem. I found the site having searched Google for 'Clio starting problems' and found your advice about changing the Coolant Temperature Sensor. Bought one. Fitted it. Car now starts first time every time! £27 the CTS cost me from Renault - a sight less than they would have charged if they'd diagnosed it themselves!! So well done, mate! If anyone else is having this kind of problem (intermittent no start, regardless of engine temperature, otherwise engine runs fine) go for the CTS!
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Do you think this will help my problem - I have an 02 reg Clio.
Sometimes the engine will not even turn - all the ligths are on but the start motor does not activate. Seems to be totally intermittent - all I do is keep trying the key in the lock, rocking the car or walking away for a few minutes and then it works.
Could be a sensor, or the ingition lock or anything?? But which sensor?
Or could it be the key fob?
I've checked the battery connections and they are ok.
Anyone got any ideas? Because it is intermittent its difficult to diagnose.
Thanks
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hello adam just a quick query regarding the temp sensor, ive been told there is a temp switch and sensor, which do you mean? i assume dont mean the sensor as this just controls the gauge?? as im having a start up problem on my n reg 1.4 clio. cheers mate
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Adam, have you had experience of MAP sensor problems?
I ask as my sons Clio 1.2 has developed an unusual fault. Starts first time but revs at high speed (guess 3,000rpm+) but drives fine - after slipping clutch to pull away!
Only way to bring the tickover revs down is to disconnect the vacuum line to the MAP sensor - then engine ticks over at normal speed if a little rough. However after doing this the vacuum line can be reconnected to MAP sensor and the engine continues to run as normal!
Just looking for some moral support before I spend £100 on a new sensor. Any thoughts?
Regards, Bill
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Hi Bill,
Very strange !! Have had one MAP sensor down on Clio a long time ago, and several where the vacuum pipe was blocked or perished, usually at the manifold end. BUT, would not expect a MAP sensor fault to produce these symptoms. MAP's primary function is to control mixture according to load - by pulling vac pipe off you are making it run full rich, and I suspect this is dragging the revs down (by co-incidence) to about the normal level.
To rev this high the throttle must be being held open (stepper motor) or there is an air leak (unlikely as it seems to go away again). My primary suspicion would be the stepper motor, which, (if it is the system I think it is !!!) incorporates a micro-switch to tell the ECU the accelerator is released. When micro switch contacts get dirty ECU becomes confused. Only test is resistance accross switch contacts, usually the bottom two of four. Should be CONSISTENLY below 5 ohms with throttle shut, open circuit with throttle open. Bad readings can vary anything between 5 and 500 ohms, different every time throttle is released. If bad only cure is new stepper motor assembly.
HTH, Adam
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Adam, thanks for your advice ? I was feeling very uneasy with my quick diagnosis.
I have now investigated the MAP sensor a little more at it appears to be working OK (close to 5V output with engine stopped and reducing to 1.5V as vacuum increases at high revs no load).
So off with the air intake hose and, as you suspected, the idle speed control valve is remaining fully open and air whistles through the idle venturi. A thumb blocking off 95% of venturi brings smooth low speed idle. Interestingly, again as you suggested, removing the MAP sensor tube does not change the idle speed control valve ? it remains open ? but the ECU must adjust some fuel setting to get idle down, but not smooth.
Unfortunately I do not seem to have an idle switch. The vehicle is an N reg 1.2 RL (early phase 3 ? I am told), with a D7F A 730 engine and multipoint injection. The Solex throttle body has throttle position sensor (3 wire pot, no switch) mounted on throttle flap and a separate idle speed control valve (4 wire stepper motor) mounted at top of the body.
I would now like to establish that the idle stepper motor is at definitely at fault and NOT some other sensor (eg throttle position, engine speed, ..) causing the ECU to hold the idle speed control valve open. Your suggestions would be welcomed!
Thanks again, Bill
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Hi again Bill,
Bit tricky, as I can't find any specs on the engine you quote, but here goes !
First it would seem that you have an Idle Speed Control Valve (ISCV) rather than a Stepper Motor, although some manuals refer to both as Stepper Motor - really helpful ! Your suspected suggestions of ISCV or TPS (Throttle Position Sensor) are top of my list too. The TPS should have a 5.0v supply, an earth, and an output signal voltage that should rise and fall smoothly as throttle is opened and closed (best tested with oscilloscope).
The only tests I can find on the ISCV for multi-point system(although reffered to as Stepper Motor !) refers to pins 3 + 2, and 20 + 21 at the ECU, but obviously the represents two pairs of two pins at the valve, both values being 50 Ohms. Even if these readings are to spec, the ISCV may be mechanically sticky - having started the engine and let it go to 3K try tapping the side of the valve. If revs drop it it likely that it is sticking, and you may have some success by removing and cleaning it (carb cleaner), but replacement likely in long term. If revs do not drop it may still be ISCV, but could be ECU instructing it incorrectly. In this case you may consider having the ECU tested before comitting to major expense - call ATP on
01543 879788 / 467466.
BOL, Adam
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Hi Adam, hopefully a final update ?..
I had previously removed the throttle body and cleaned the idle air control valve but thought I?d give your ?tap with a screwdriver handle? a try ? no joy.
So after checking the remaining sensor outputs (throttle position and inlet air temp), which both looked OK, I was back to a fault with the idle air control valve or the ECU. What I really wanted to do was get the idle valve to move, at least a little, proving that the ECU was providing the right output. I had seen some instructions on the web to ?initialise? a new IAC on another model Renault ? thought I?d give it a go (couldn?t hurt) :-
1) Turn ignition (do not start engine) wait 10 secs then remove IAC connector
2) Turn ignition off, wait 10 secs then replace IAC connector
3) Repeat once more
For info ? checking the connector immediately after it was unplugged showed that the ECU continues to pulse the IAC for several seconds after ignition off, which presumably is the reason for a 10 second wait.
After this procedure the IAC was fully closed! ? in fact on first starting the engine it would not tick-over without some throttle. Well this was progress ? but as I had obviously managed to persuade the ECU to close the valve how did I now get it to normal operations. After stopping the engine I then left the ignition on for a while before starting again ? only on the basis that the ECU does seem to talk to all this kit before starting and for some seconds after the engine has been turned off ? and eureka she idled and drove beautifully.
So it appears that the IAC was motored into the fully open position and either physically stuck there or stuck there by the ECU ? it would appear to be the latter. If so, time will tell if this was a result of a flat battery (just before the fault appeared) or some other obscure fault that will cause this to happen again. In the mean time my son is happy to be mobile once again.
Many thanks for your helpful advice, which kept me on track.
Regards, Bill
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Hi Bill,
Certainly hope your persistence has paid off. If so, well done.
As you say, you now have to give it a few days to see if improvement is maintained. Please do come back and lets us know if it is. Or isn't !!
Regards, Adam
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Dear Adam, your advice was excellent, My local garage cleaned out various bits of the engine, of my renault clio, but still would n't start from cold without a lot of chugging and smoke. I though I would try the internet for advice, couldn't believe my luck really, I typed in 'renault clio starting problems', and found your reply. Phoned Webcon to get CTS, took sometime to find out were it was located, but after replacing old one it now starts well.
So Thank you very much!
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Adam,
Had a problem starting a 1993 Clio 1.2, engine turned over but would not fire from cold, so surfed the net for any ideas. Turned out your advice to Phil in Oct 2002 to replace the Coolant Temperature Sensor was spot on. New one cost me just over £10 from my local Renault dealer, removed the distributor cap & rotor arm to aid access, job done in about 20 minutes. Car also over revs on idle from time to time so hoping a new CTS may have solved that too. Thanks.
Rob
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