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Rough idle, 172 Cup



massiveCoRbyn

ClioSport Club Member
  Several
Hello guys and gals.

New to the forum and have a question. I've done some searching on this, but so far not managed to find anything that quite matches my symptoms. My '53 Clio 172 Cup seems to suffer from a rather poor idle, enough to make the car shake quite badly at times.

Generally the car drives well, starts fine, and pulls cleanly to the redline, but does seem to suffer the following:

When you start the car, the idle is ok, it sits a bit higher initially, and then drops away, as you'd expect with any car. However, once it drops, it then begins to get very lumpy. The tacho needle doesn't pick it up, but the idle is obviously very lumpy, far more so than other 172s I've seen. It doesn't cut out, or hunt, but is just very rough, like an old car with a really harsh cam in it. If you leave the car idling for any length of time, the emissions warning light will often begin to flash. After flashing for a period, it will often go out of it's own accord or, if you drive the car, it then goes out. The light never flashes or comes on when driving the car normally.

When you drive the car cold, it can also feel quite hesitant at light throttle. If you accelerate with any vigour at all, it feels flat, but I believe that's normal for these, and obviously isn't something you should do anyway. However, for example, if you are driving along in 4th at around 30, or in 5th at around 40, the car can feel like it's missing slightly or is hesitating. Once the car is warm, this is much less pronounced.

The other symptom seems to occur when in traffic at very low speeds. If you're crawling along in 1st gear, or at very low revs in 2nd, the car can feel very unhappy, and tries to bunny hop quite a lot. This might partially be down to how the car is, as I'm more used to bigger cars with bigger engines, but it does seem slightly excessive.

As I say, generally the car drives well and pulls fine, but this is a bit annoying and, with the MOT fast approaching, I don't want it to be failing on emissions.

To my knowledge, it's all standard apart from an induction kit. I've replaced the pre-cat lambda sensor, and have ordered new plugs, but thought it would be worth getting other opinions, as I've read lots about throttle cleaning, TDC sensors, timing issues and various other things, so don't want to just waste money replacing parts.

Thanks for the help.
 
  Pug 206 SW, 172 CUP
Sounds very similar to the symptoms I used to get from uprated cams in older cars. I would suspect timing unless you have reason not to.

They aren't great from stone cold anyway but mine never feels like it's missing or bunny hops. Again symptoms I've had with old school tuning.

Your dephaser working ok?

Injectors faults are pretty common on these so their could be an issue there.

Make sure you order the correct plugs for it. They seem to be very picky these engines.

If your ok with car mechanics and can get hold of a horseshoe timing tool and a crank pin for the F4R it is pretty easy to check the timing. Basically if the tools won't fit it's out. Any old rubbish for this is ok to check but you need genuine tools that don't bend to correct it.

Search for timing threads for more info eg. How to check you definitely have the crank pin in the right place before attempting to fit the horseshoe tool.
 
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massiveCoRbyn

ClioSport Club Member
  Several
Plugs-wise I've ordered some from a Renault dealer as I got them for a decent price. They're the NGK Platinum ones that people seem to talk about in threads I've seen.

Is it easy to test the injectors?

I should also add that I plugged a friend's RS Tuner into the car and it didn't come up with any engine related fault codes.

As for the dephaser, are there any tell-tale signs? I'm by no means experienced with Renaults. I've heard that they can rattle, and I don't have any notable rattles from the engine. There is a clear "kick" when the car comes on cam at high revs, which would suggest that it's working. I think the car is about 15k miles off it's next belt change, but I'd have to double check that for sure.

I'll have a bit more of a search for timing stuff, as it might be good to check it out if it's cheap, as at least it would eliminate it.
 
  Pug 206 SW, 172 CUP
Bad timing can cause a bigger kick.

As for the injectors easiest thing I guess is to pick up a second-hand set or one new one and swap one at a time or put the whole spare set on and see if there is any different. That is if you can't afford a new set. Someone recently found they only need to be a little bit off and they can cause quite an issue.

Check the bottom of the coil pack hasn't cracked. I cured a misfire on mine by putting a secondhand coil pack on.

Had a look for cheap tools to check and they are around the 40-50quid Mark. So it maybe not much more to get a specialist to have a quick gander.

If the timing is far enough out you can tell just with a crank pin as it's visually obvious that the Cam tool wouldn't go in. This engine only needs to be a wee bit out and it suffers unfortunately.

The search on this forum is pants but if you persist all of this has been covered many times.
 
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massiveCoRbyn

ClioSport Club Member
  Several
1st lambda has already been changed, but that didn't make any difference unfortunately.

Plugs have been ordered, not leads though. I was thinking of doing them, as I don't know when they were last done, so it's probably not a terrible idea, but not really sure what to go for with those.
 

massiveCoRbyn

ClioSport Club Member
  Several
As I say, plugs and things are on the list, as they're easy and are service items anyway so, without knowing when they were last done, changing them is probably not a bad idea.

On the coil pack and lead fronts, what is the deal with new ones? Presumably buying from Renault is going to see my pants pulled down. ECP sell this: http://www.eurocarparts.com/ecp/c/R...8fd9da1d4e102cb27833c41faca6f87b2c400a&000197

Anyone tried it? There's plenty of used ones on eBay, but you never know what they're going to be like.

For leads, I'm not really a believer in all this aftermarket, super-duper silicone nonsense, especially when the car is standard and they cost best part of £100, but what non-genuine ones are available? Are there any brands that should be avoided?

First call with the coil pack will be to try and borrow the one from my friend's 172, as that's an easy (and free!) test to begin with.
 
  Pug 206 SW, 172 CUP
If he doesn't mind borrow the leads as well. A but more faff but could save some time and effort. Depends on how happy he is for you to pull bits off his Clio. He could try your bits as well to see if you can recreate the fault on his car with your bits.

If I buy non genuine parts I try to buy them from manufacturers that supply OE parts. Most car manufacturers these days don't make their own parts. Pulling my Peugeot apart was a big eye opener.
 
  dan's cast offs.
I should also add that I plugged a friend's RS Tuner into the car and it didn't come up with any engine related fault codes.

don't trust rs tuner for diagnostics, had two phase 1's both with eml on, rs tuner said no faults on either of them. get it plugged in to something half decent at least before you go wasting money changing parts 'just in case'
 
  Pug 206 SW, 172 CUP
RS tuner is probably just a generic OBD reader. I wish Renaults Clip was as easy and cheap to get as the stuff Peugeot/Citroen use.
 

massiveCoRbyn

ClioSport Club Member
  Several
Sorry, bit of a delay.

Just to update things a bit here. I borrowed the coil pack from a friend's 172 for a couple of days and it didn't make any difference to how the car ran. When I removed mine, I did notice that it was quite badly cracked, and there was evidence of corrosion, so I've ordered a new one anyway, along with HT leads. Plugs have arrived so that will all be fitted together. No idea if it will fix the problem but, as I had no idea when they were last done, and the coil pack was obviously damaged, it seemed a prudent move.

The car passed it's MOT anyway, so at least the pressure is off for a quick fix. If the plugs/leads make no difference, I'll see if I can sort out a proper OBD plug-in to see if that brings up any codes.
 

massiveCoRbyn

ClioSport Club Member
  Several
And another update!

I was driving it earlier and when I accelerated from low revs in third gear at light throttle and it had a big cough. Went ok after that but just stuttered once.

Anyway, when I got home I changed the plugs, leads and coil pack. Whilst it hasn't made any difference in itself, it did raise something interesting when I removed the old plugs. For cylinders 1, 2 and 4 the plugs were quite white, suggesting it might be a bit lean. However, for cylinder 3, it was black, so that suggests it's rich.

Anyone got any thoughts on that?
 

massiveCoRbyn

ClioSport Club Member
  Several
does sound that way. Plugged a friend's ODB reader into it and it said misfire on cylinder three.

What kind of job is it to do the injector?
 
  172 Cup
I have the exact same fault on my 172 cup below 2000rpm if you accelerate it will hesitate and stutter I've tried a lambda but it's still the same so I'm thinking injector as its recently had plugs and leads and the coil looks ok unfortunately it's going to have to wait for a bit as I've got tax mot and insurance all due this month
 
  clio v6
injector change is easy can do all 4 in no time.buy the rentec ones off ebay £32.50 each these are the genuine ones others will give you poor starting issues.
 
  172 Cup
They seem to have gone up to £35.50 if you search clio 172 injector they are the first ones that come up
 

massiveCoRbyn

ClioSport Club Member
  Several
I ended up buying one from ECP, fitted it last night. Not driven it much since, but it appears to be idling better.

It looked like number two was quite new, so I guess that has already been replaced at some stage. The others all looked pretty old though, so I guess were original.

Will see how it goes over the next few days. Decided to cheer myself up by booking a track day this Sunday!
 

massiveCoRbyn

ClioSport Club Member
  Several
Yes!

Injector change made a big difference, idles much better and no more toxic fume warning light flashing.

Still not sure it's perfect but it's a lot better. Going to replace the other two old injectors at some point too.

In other news, did a track day at Snetterton yesterday and she performed admirably!
 
THE FIRST POST IS MY EXACT ISSUE! Well written up!

I have a new OE coilpack and 4 x injectors to try next as I have an ECP coilpack I'm untrustworthy of, only did the OE NGKR plugs not long ago on a full service and Dan@SJM did the belts and dephaser 18 months ago so it's been good.

All the threads on here dont have an outcome 😧
 
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  182
My 182 cup does this too but was unsure if it is to go with the exhaust, updated inlet manifold and remap.....

Only purchased recently but may have to investigate.
 

massiveCoRbyn

ClioSport Club Member
  Several
Changing the injector transformed it. I plugged a friend's diagnostic reader into it and it was recording a misfire on cyl. three. When I replaced the injector on that cylinder, it made it a lot better. Idled much better and behaved much better when cold.

That being said, it has gotten a bit worse again lately, but not sure what that is. Assume it's a different issue!
 

npt

  BMW 320d- 172 cup
My one is exactly the same as you describe, you'd think it was cammed, I changed the plugs and it was a lot better, but after 1000mls it's back the same, it gets a bit bogged down when pulling off also but has bags of power, I've had all belts/dephaser done by a specialist, I also asked if it was out when he took it apart in he said it was spot on, I'm thinking injectors and first lambda
 


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