rough idle cup 172

[renaultsport1889]

The idle on my cup 172 is a bit lumpy even when it has warmed up and is doing my head in. I have recently had it serviced, spark plugs, HT leads, coil pack but still seems lumpy. Any ideas???

 

[Dip]

How does it feel under load?

 

[SRIDENZ]

Mine is similar. Spluttery on tick over and absolutely smooth as baby bum under load. Interested to see wot others say. I assumed it was to do with the low tick over/idle.

 

[renaultsport1889]

Its fine under load, its only when I'm sitting at traffic lights and that it feels quite rough. The rev meter doesnt move about at all

 

[jinjur]

Im only new to this game chap but im starting to learn that these wee donkeys are right lumpy pigs and its normal.....as long as there is no stalling etc.

Jj

 

[edewer]

idle generally seems to suffer after belts have been changed for some reason. dont ask me why though.......

 

[Mister_G]

I have a similar problem, chaging my plugs helped alot (although I see you've already done that!).

The only thing left to do in my engine bay is to get some new mounts, but I don't think that will stop it completely....

As above idle is crap on 1*2's from what I've heard, I'm just gonna learn to live with it... I've heard that RS Tuners help resolve the lumpy idle though???

 

[jinjur]

idle generally seems to suffer after belts have been changed for some reason. dont ask me why though.......

At Renault or independants......or both?

Can we assume that they are not being timed/setup correctly then?

JJ

 

[st3ve]

If the rev counter sits tight at just over 1k on cold and iirc just under 1k when warm I wouldn't worry about it.

If it's up and down like a yoyo and it's like this consistently then you have an issue.

 

[sideways danny]

idle generally seems to suffer after belts have been changed for some reason. dont ask me why though.......

I've noticed this on some cars. Normally when they've been timed up wrong before being re-done.

 

[497adam]

So danny what your saying is when they have been wrong then corrected they seem to idle badly?

 

[renaultsport1889]

Thanks for the replies guys. Could it be a faulty intake air temperature sensor? Could the timing be out a fraction? If so, how do you get it re set? Excuse my ignorance!!

 

[ianysm]

Surely if timing was out you'd notice it throughout the rev range?

 

[sideways danny]

So danny what your saying is when they have been wrong then corrected they seem to idle badly?

to some extent yes. the way these engines are, when the timing is set wrong, it makes the cam setup milder which gives a smoother idle due to less overlap.

 

[st3ve]

Surely if timing was out you'd notice it throughout the rev range?

Not unless you know the difference between one properly timed and one not.

The inlet cam on mine was out by 15 degrees and I had no idea until it was RR'd.

Too many monkeys in this world who THINK they know everything.

 

[J.B.]

Same problem here. Smooth under load but idles roughly. Revs don't move jitter around though so I can live with it. However it doesn't always start first time in the mornings so I need to take a look at the TDC sensor.

 

[497adam]

Mine idles roughly when warm since cambelt done and timing corrected, thius sound right danny? does seem to go better though

 

[TONKA84]

Sorry to bring up and old thread. However, mine is the same.. Fine under load, but again, spluttering and it feels like the engine is jumping around when idle. Even cold or warm, the needle is sitting below 1k! Is this the norm then, or should i do something about it??

Cheers

 

[jamesd1263]

Mine idles gash when warm looks like a common fault

 

[Greeny.]

Mine has done this for 3 years, worse when cold, how bad is it though? They are all abit rough on idle.

 

[jamesd1263]

Drops to 500rpm I'll give everything Nice clean after work

 

[Soot1e]

There have been many threads about rough idle, especially on 172Cups, on this forum and most people tend agree it's normal. Some have had remaps and had the fault cured. I'm going to have mine done in the near future.

 

[gez 172]

mine is lumpy on idle, idles just over 1k, fine once its warmed up though, idles at 500rpm when warm.

I'd say some people need their lambar sensor changing, should help.

 

[Soot1e]

mine is lumpy on idle, idles just over 1k, fine once its warmed up though, idles at 500rpm when warm.

I'd say some people need their lambar sensor changing, should help.

Changed my Lambda and it didn't make the slightest difference.

 

[j26]

mine is a 172 and has quite rough idle but does cut out and needle on rev counter sits constant, but under load it misfires like a b*****d!!! plugs are coming out tonight to see if there is any difference to see between them, but they were new 3000 miles ago???
sorry dont mean to take over the thread.

 

[.Stevo.C.]

mine is a 172 and has quite rough idle but does cut out and needle on rev counter sits constant, but under load it misfires like a b*****d!!! plugs are coming out tonight to see if there is any difference to see between them, but they were new 3000 miles ago???
sorry dont mean to take over the thread.

Mine tries to cut out occasionally only when on idle. Totally fine under load though strange :S

 

[Gaz_]

A RS tuner will map a lumpy idle speed (and riase it slightly) I got one specifically for that reason. Worked a treat. SO get a second hand one, unlock it, load up the 98ron map, sell it on. Doing it that way costs no more than about £30..................... However if its proper lumpy, it could indicate timing issues (bad lol)

 

[.Stevo.C.]

The idle on mine is not that bad tbh it's just the cut out thing that is strange, I have started filling up with Bp Ultimate and it has smoothed the idle out a tad. I am going to get a remap at Rs tuning this year to cure it though.

 

[Gaz_]

Just get an RS tuner, and do it your self. An RS tuning remap wont be £180 better

Saying that, on a phase 1 not sure if a remap will help idle as it has a cable TB

 

[.Stevo.C.]

Well my brother is getting his 225 cup done there too so i though why not get mine done . I'm not sure on that one either mate don't know if it needs tweeked a little more.

 

[Gaz_]

Do they not have a grub screw to adjust the idle speed? The phase 2 with its dbw is all electronic, hence it can be mapped to suit

 

[.Stevo.C.]

Not had a look for one so a couldn't tell you, I will have a look tomorrow. Not really up for mucking about with it if there is one tbh.

 

[Rhod.L15]

Hmmm, I've been having similar issues as detailed throughout this thread. First noticed it about two months back, very lumpy on idle and misfiring quite badly. I took it down to my local garage which is an ex Renault franchise where they cleaned the plugs and all was fine until earlier this week, when I had to leave my car at my workplace overnight (secure compound!) so it didn't move for almost two days, after which I fired it up and the lumpiness was back. When the engine was cold it was misfiring slightly when under 3k revs, but when above that it pulled fine. Once onto the M4 and warmed up sufficiently the apparent misfire disappeared and it was smooth as silk. Fired her up again this morning to go to work with no problem and the same coming home.

Belts were done about four months ago btw.

:S

 

[sortedcossie]

Just thought i'd resurrect this thread.

My modded 2001 172 (RS tuning remap, matched inlet and throttle body, yozasportt cat back exhaust, noise valve removed from airbox) has developed this lumpy idle problem when warm, it doesn't try to cut out, it just stutters like it has a momentary misfire.

This problem only started after a cambelt service (belt, tensioner, & dephaser as a precaution). I noticed it the moment I got in the car and thus it was taken straight back to be looked at. The timing was initially out by a fraction so this was rectified and is now spot on (at the same time the new type crank pulley was fitted), its been treble checked. There was a bad connection on the throttle sensor, but this has now been fixed too. It has also had another set of fresh spark plugs and there are no fault codes in the ECU.

The car is run on normal unleaded most of the time so i've ruled this out as it was fine before. I have read that this problem does appear after a belt change, has anyone found out why? Or fixed it?

Its starting to cause arguements now as i'm refusing to pay the bill until its fixed, my arguement is that it wasn't doing it beforehand.

 

[Hashiriya San]

Mine also idles lumpy I suspected after owning various french cars with ph3 cams and the way mine pulls quite hard further up the rev range that this had been cammed as all my cars previously ran rubbish my j4 106 xsi was on throttle bodies and ph3s running over 170bhp and that didn't like cold starts especially on a cold morning this suffers the same small blip on throttle if its cold and its fine and when warm it starts ok too but always idles poor but not quite as bad as a cammed j4 lump, it doesnt hunt etc it sits firmly on the rev counter I just thought this must of had some uprated cams but it only revs to just below 7k and I haven't really looked into it as its not caused an issue. But seems its just a common issue so I could do with putting my car on a rolling road.