Rough on Idle dropping below 1000 revs running Bad

[bryera]

Hay guy need your help my 172 cup seems to be relly rough on idle and keep droping below 1000 revs on the rev counter. It is running like it just wunts to cut out the smell of petrol is relly strong i no i have a D Cat on it but its a littel to strong to say its the D Cat.i have cleand the throtle body thinking that would do it but still no joy. i have had one of my good mates from cliosports on here sit in with me and try to identify the problem i will upload a video of what its doing but untill then dose any one Know.

Thanks Adam:approve:

 

[bryera]

https://www.youtube.com/watch?v=vtBh1JhlA2Q&feature=youtube_gdata_player

 

[JoshE93]

i have the exact same problem on my 1.2 16v but its missfiring on cyliner 2 ive changed all spark plugs but no change took it to a garage today they said its possibly a fuel injector or at the worst a cracked head

 

[bryera]

Yer but at top end its fine so would I not see power loss if it was the fuel injectors thinking and hoping it just the spark plugs if that a big job and costly ??

 

[Nyall]

Spark plugs aren't expensive mate, and it's not a big job, you could do it yourself, it's pretty straight forward.

I have this exact problem with my 1.4, the rev needle drops dangerously low and sometimes it will cut out. I changed the spark plugs but this had no effect. When I start her up I just hold the revs at 1k-1.5k for a few seconds while i put my seatbelt and specs on lol it helps a little. I've just learned to live with it tbh, but it's bloody annoying!

 

[bryera]

Yer that's what myn is doing its doing my head in I relly wont to know what it is buging me big time but your right needle keeps dropping

 

[Dan519]

Lambda

 

[bryera]

Was what I was thinking at 1st but mate put me off that idea but would a lambda do that ??

 

[bryera]

Thanks Dan I will look into that to now its a easy thing to just swap rand to see if it is staves seems to say he trusts your say so will give it a go mate thanks but thank you to all that's help will post up tomorrow if all is well

 

[Dan519]

idle speed seems normal BTW, 850rpm is about ideal

 

[Ade182]

It's seemed to stop trying to stall since we took it for a blast but it still idle hunting a little. It sounded pretty poorly when I first turned up and it idle hunts much worse when you first start it.

Dan, thanks for your help so far.... can the lambda just been cleaned and re-installed or do we need to get hold of a new one? And I'm assume its going to be the pre-cat sensor thats the culprit?

 

[st3ve]

You can swap them around Ade and yeah, the post cat lambda has no effect on the running of the engine.

 

[Ade182]

So knowing how much of a cheap skate he is, we'll be swapping them around!

 

[bryera]

Right !

 

[Ade182]

It's not the pre-cat lambda. We replaced it and its running just as bad if not worse! Could the after-cat lambda cause this as from my understanding it shouldn't?

Went to Renault and the mechanic reckons it's misfiring on a cylinder, however is unsure until its scanned at a cost of £75+vat just for the diagnostics alone! Jesus!

However I'm starting to think ignition?

 

[Lloydy]

It's not the pre-cat lambda. We replaced it and its running just as bad if not worse! Could the after-cat lambda cause this as from my understanding it shouldn't?

Went to Renault and the mechanic reckons it's misfiring on a cylinder, however is unsure until its scanned at a cost of £75+vat just for the diagnostics alone! Jesus!

However I'm starting to think ignition?

Have a look at your ht leads going in to your coilpack, check for any rubbing marks or white marks on them if so wrap these areas in electrical tape for the mean time and replace them. While your there check the connectors for corrosion and clean if required. Thats where i would start

 

[Ade182]

Can the coilpacks that go into the box at the back of the engine be safely tested? So then we know whether to look further towards the engine?

 

[bryera]

No body can find out what's rong with it had a RS Tuner on it been to 3 garages and they can not find any thing but yet its still running s*#t and cutting out on me so I have booked it into Renault I no its not going to be cheap but can not think of any thing else. I will let you all know what was said after Renault rape on repairing it lol :approve:

 

[Russ_16v]

does it drive ok or is it sluggish?

it wont be leads/plugs as 99% of the time those would cause as issue al any revs, not just on idle

I would still say a new lambda would not do any harm at all, both lambdas could be up the creek.

if it smells strongly of fuel then it is over fuelling, so lambda, or coolant temp sensor would be a possibilty.

 

[bryera]

No mate its not lambdas I got a new one and still no joy but like I say been to 3 garages and they can not find any thing but do not wanted to keep spending cash on what it could be so that's why its going in to Renault lol booked in Tuesday so will find out then.and yer it drive sluggish on low revs but at speed and high revs its ok and cuts out on low revs too.

 

[Russ_16v]

hmmm, quite odd there mate!

have you a specialist near you? Just afraid Renault may charge you a lot for diagnosis work.


When was the cambelt last done? Timing may be out

 

[bryera]

Na cam was done about 7 month ago so that's ok but yer they charge £80 just for a diagnosis and the only specialists is Birchdown but I am away now on security on the Olympics so got my old man doing it and its a little to far for him to go but that was the 1st plas I was thinking but just wunt it done now

 

[mossyv6]

Clean the internal of the throttle body mate

 

[bryera]

Done lol thanks

 

[bryera]

Thanks for all the help CS been relly help full and mayed me think of things I did not no it could be !

 

[bryera]

Well its in Renault and funny thing is they do not no what it is and start feeding me with a lot of bull S*#t so ones I am back think its a job for Birchdown coz there no way I am paying Renault when I could pay Birchdown to do it and feel happy with the work so will just have to wait

 

[st3ve]

I mentioned this to the guys at Birchdown as I was there today and they said purely off the symptoms I've described to them that it could be MAP sensor or the PAS senosr (if that's the right name?).

 

[bryera]

Well thanks to Steve and Birchdowns Advise i got my self a new MAP Senser and its running a lot better there still a littel some thing i can not put my finger on but a hell of a lot better. Funny really that i take it to Renault in Blackpool and they do not have a clue but are happy to leave me with a £80 bill for trying to find what was wrong lol but next thing is oil chang see if it make it any beter :approve:

Thanks Guys

 

[Cw Tuning.]

to me sounds like either an airlock in cooliong system, a false air leak, or coolant temp sensor, the cts can cause this as it will make the engine overfuel. good way to diagnose is to take a temp reading of the block. if its stupidly low its overfuleing as the fuel will cool the block try that mate?

 

[Dan519]

to me sounds like either an airlock in cooliong system, a false air leak, or coolant temp sensor, the cts can cause this as it will make the engine overfuel. good way to diagnose is to take a temp reading of the block. if its stupidly low its overfuleing as the fuel will cool the block try that mate?

erm....that's not how it works at all. Yes a faulty CTS could cause overfueling, but the extra fuel doesn't cool the engine down, or certainly not to any discernable degree where you could tell from the external temperature of the block.

Compression test needed

 

[bryera]

erm....that's not how it works at all. Yes a faulty CTS could cause overfueling, but the extra fuel doesn't cool the engine down, or certainly not to any discernable degree where you could tell from the external temperature of the block.

Compression test needed

Thanks Dan lol

 

[bryera]

Bringing it back up i know but when you put a new MAP sensor in.Do i need a RSTuner to turn the fault off or will it just go because i geting good MPG at the moment but still lumpy ?

Thanks for all the help so far be happy when i get down to the problem !

 

[bryera]

http://www.cliosport.net/forum/showthread.php?661864-lumpy-Idle-amp-Cutting-Out-!!!