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Mike
Mike, Mechanic
Category: Car
Satisfied Customers: 38802
Experience:  Hi, I have been a Car/vehicle mechanic 34 years. 29of -running my own repair/diagnostic business.
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Renault Megane Classic sedan: megane 2000 1.6 16 valve Car

Resolved Question:

megane 2000 1.6 16 valve Car was running perfectly until mid Dec when crank pulley inner and outer came apart causing aircon belt to snap.This resulted in belt particles getting into the cambelt gears.This caused cambelt to slip a gear resulting in bent valves. Head has been redone , valves replaced, the idle control valve as well as the ignition sensor have also been replaced. The mechanic cannot get the ideling to stabilise at correct revs, it just continues going up (2000 - 2500 revs) Its 2 months later, we cant use the car and the mechanic & auto electrician canot get it right!! PLEASE HELP!!!


How long will we wait for an answer?

Submitted: 1 year ago.
Category: Car
Expert:  Mike replied 1 year ago.
Hello and Welcome to justanswer...

My name isXXXXX happy to help you with this...

Please tell me at this stage, exactly what fault codes have been retrieved ?

Rgds, MIKE................................


Customer: replied 1 year ago.


I think it indicated the ECU. That was then taken out and sent to JHB for checking and has come back, been fitted and they say the readings are all correct.


 

Customer: replied 1 year ago.


Is it normal for so many things to go wrong following the aircon belt snapping?

Customer: replied 1 year ago.


Any idea how much longer this will be ?

Expert:  Mike replied 1 year ago.
Hello again Les...

Our posts crossed im afraid.

It takes me to time to give thought to your situation and then to type out your reply...so sorry about that. My reply that I had typed put is as follows :


There's a few things to consider here. You say this has gone on for some two months now... One would have thought the cause would have by now been seriously narrowed down..

It's not so much that the ac belt broke, in line with you asking is it normal for so many things to go wrong...of course this was the root cause of your trouble...anything that cases the timing chain to come off / jump will cause this. What you basically have though is a running fault now but this CNN b for several reasons /several causes ...which you need to trace down.

I'm assuming that they decided that it must be an ecu fault because they couldn't find the cause but as I say, there are several things that can cause what you describe on these.

For example, it can be an air leak...induction air leak into the engine, unmetered air will cause this for sure. Following on from that, a faulty air meter / system will Los ...so that system needs checking - as does the circuit controlling it.

The same applies to the idle control circuit .. It's no good replacing the idle valve for example if the engine has unmetered air ingress or the air meter or idle valve has a fault such as no electrical circuit to the components, so those things need checking thoroughly.

If the fault light is on on the dash when're engine is running, then as mentioned at th outset, it needs fault code reading to get an idea of what's wrong.
It would be very unlikely that the ecu had failed...but again, go off the codes nod importantly, check its CIRCUIT before condemning or even bothering to send the ecu for test. As iit's come back tested ok, then for sure you are back to code reading and circuit testing now.

So given what you have told me so far, those are the ways forward now... Let me know how you get on or if you need anything else..

Best rgds, MIKE.

Please do click on the OK - Excellent Service ratings for me now, Thank You in advance for that.

Again then if you do need to get back to me at anytime on this, you can do...just come back to this post and re reply to me.

Rgds, MIKE.

Customer: replied 1 year ago.


Hi Mike, I certainly hope you are on line tonight!


 


I consulted with the mechanic and auto electrician today regarding the info you supplied. They advise that this vehicle does not have an air meter. They say their next step on Monday will be to recheck the electric circuits that control the idling and to compare it to a vehicle with a similar engine to see if they get the same readings.


 


I must mention that when you first start the car the idling is fine but after driving for about 10 minutes it just starts rising.


I spoke to someone today who suggested that they should replace the O ring of the throttle body where it attaches to the engine.


 


Can you give me any other advice? We are really desperate to get this car right now... after all its been with the Mechanic for two months!


 


 


 


Regards


Les

Expert:  Mike replied 1 year ago.
Hello again Les..

Thank you for your message... Im afraid I wasn't on yesterday, it was my time off Im afraid.

There are many differing versions on the engine management system on these - I only mentioned "air meter" as one option - obviously if it doesn't have that then it has the Map system which they should know to check / deal with. All the other things things I mentioned to need checking with this issue you have... Too, the Map system is vacuum controlled , again they should know to check this. Also , you mention the throttle body mount -yes, this would all come under "checking for air / vacuum leaks etc " - as I mentioned above.

Too - specifically with the engine revs raising as you describe, they need to get the engine hot when testing - seals, "o" rings , ( on injectors etc ) and so on tend to expand with the heat , they can then lose their seal and you get the air ingress - hence the revs raise. Thats a common cause of this - again, all needs to be checked as I mentioned above.

Only when all possibilities of un metered air are ruled out should one then move on to checking the engine management system ( with no fault lights on that is ).. as the EMS will always attempt to compensate for the problem - so you can be going round in circles if its not checked correctly. A plug in diagnostic on Live Data mode should be used to check the working of the o2 sensor etc as well.... this helps to trace if there are intake leaks. Too, the vacuum should be checked on the engine - this should be between 18-22 mg.. ( on a mercury vac gauge )... major deviations - usually low, indicate a leak.

A common issue ion these models is wiring faults - chaffed / rubbed through wiring on the EMS.. if this happens you get the Ems Ecu not able to communicate with the sensors and so on - and likely the Idle control side of things...so that should be checked for also- again - a very common issue on these. If there is not a signal - or an erratic one to the idle control -but the ecu is ok, the fault is in the wiring - to be traced / found and fixed.

Working through as above will get this sorted for you one way or the other..

Let me know if you need anything else -

Best Rgds, MIKE.

...... Please do click on one of the OK~ Excellent service ratings for now please - as that is how I am credited for helping you... Thank you for that ....and you are Welcome back anytime..

Rgds - MIKE..
Mike, Mechanic
Category: Car
Satisfied Customers: 38802
Experience: Hi, I have been a Car/vehicle mechanic 34 years. 29of -running my own repair/diagnostic business.
Mike and other Car Specialists are ready to help you
Customer: replied 1 year ago.


Thanks Mike. I will discuss this with them on Monday and see how far we get now.


 


Regards


Les


 


 


 


 

Expert:  Mike replied 1 year ago.
You are very welcome Les..

I hope that they get it sorted for you...

Im always here... if I can help anymore at all, let me know.

All the best - MIKE.
Customer: replied 1 year ago.

Hi Mike

The car is still at the auto electician who is now checking the wiring.

I have discussed your last info with the mechanic who advises us to let you know all that he has done thus far:

vacuum leak test - tested for air leaks

scoped map sensor - pass

scoped idle air control - fail

tested IAC (brand new) pins A & D 50 and pins B & C 50 (omes)

scoped pin out at ECU

Engine idling

ECM pin 41 - no signal

pin 12 - no signal

pin 42 - no signal

pin 72 - no signal

 

IGNITION ON ....................Book Values

ecm pin 12 - 12.46 v ..........Battery voltage

41 - 0.03 v.......................... Battery Voltage

42 - 0.03 v.......................... 0.3 v

72 - 0.03v............................ 0.27v

 

Two fault codes on ECM that will not clear no number for codes only description:

***idle control mal function.

 

 

If you are able to look through this info, we would appreciate any further suggestions.

 

Thanks so much

Les

 

 

 

Customer: replied 1 year ago.

 


Hi Mike


The car is still at the auto electician who is now checking the wiring.


I have discussed your last info with the mechanic who advises us to let you know all that he has done thus far:


vacuum leak test - tested for air leaks


scoped map sensor - pass


scoped idle air control - fail


tested IAC (brand new) pins A & D 50 and pins B & C 50 (ohms)


scoped pin out at ECU


Engine idling


ECM pin 41 - no signal


pin 12 - no signal


pin 42 - no signal


pin 72 - no signal


 


IGNITION ON ....................Book Values


ecm pin 12 - 12.46 v ..........Battery voltage


41 - 0.03 v.......................... Battery Voltage


42 - 0.03 v.......................... 0.3 v


72 - 0.03v............................ 0.27v


 


Two fault codes on ECM that will not clear no number for codes only description:


***idle control mal function.


 


 


If you are able to look through this info, we would appreciate any further suggestions.


 


Thanks so much


Les

Expert:  Mike replied 1 year ago.
Hello again Les..

Im sorry I could not get back to you earlier -

There are two things that stand out here Les.. Either a faulty Ecu ..or wiring / connections..

If you are saying that he cannot get anything out of the ecu at the ecu pins, this would indicate Ecu - While I know its been tested - that would indicate it needs to be sent..I would say, elsewhere. I have a suggestion in that case.. to send the ecu to for "re" test... give this company a call on 0 1 6 3 4 ... 6 8 7 2 2 2 ..

If I have not understood you correctly, let me know, otherwise...its as above on this one Les..

Best Rgds, MIKE..
Customer: replied 1 year ago.


Hi Mike


 


Please give me more info on the company I should contact regarding the ecu.. I tried calling the number you gave me and it just said it doesnt exist.


I am in East London, South Africa.


 


Thanks


Les

Expert:  Mike replied 1 year ago.
Hello again Les...

If you are outside the UK..- If thats right - you need to use the +44 ... in place of the initial zero on the phone number..

If you still have trouble let me know - I wasn't aware you were not in the UK though - if thats the case -you may be better locating such a company nearer you Les...

Rgds, MIKE..
Customer: replied 1 year ago.


Hi Mike


 


The auto elecrician resorted to fixing the idle air control in a permanent position by glueing it.


This allows the car to idle at 1100 rpm and when the aircon is on it drops to 900rpm. This has enabled us to use the motorcarsince yesterday. I am however concerned about the long term effects on the engine. Could this have an adverse effect on the cars performance?


 


Kindly let me hae your view on this.


 


Regards


Les

Expert:  Mike replied 1 year ago.
Hello again Les..

There wont be any long term effects on the engine on itself or performance ..other than of course its idle..

Its obviously not ideal - but it will be ok in that sense...

Rgds, MIKE.
Customer: replied 1 year ago.


Thanks so much!

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