Misfire

[Johnson.]

We have just changed the cambelt on a clio 172 and after starting the car for the first time the car appears to be misfiring. I am unsure how it sounded before as i bought it as a non runner.

The car is running very lumpy on tickover but from around 3k revs the misfires seems to dissapear. We have also noticed that the longer the car is left to idle the smoother it begins to run.

The airbox is currently off the car and i am wondering if this is what the cause of the problem is ? It sounds like a bit of a silly question as i read it back as it will sound lumpy without an airbox on, but im not sure if it explains the misfire or not ?

 

[InfernoPaul]

I am having this problem as well, could be timing or coil pack

 

[dangerous dave]

these cars are old and injectors are dropping like flys these days..

Some of these things can be checked easily if you have a friendly member local with some spares to use for trial and error, or perhaps whip off there 100% working coil pack etc for a test..

I'm sure rad temp in past renaults has effected idle and running so never rule out other areas.. It's a Renault and a worn wiper blade can cause a misfire.

 

[Cub.]

It could be a number of things, anyone nearby with a RS Tuner or OBD Reader? It could be any of the following, and this list isn't exhaustive;

- Injectors
- Timing
- Coil Pack
- HT Leads
- Pre cat lambda

Takes some reasonably straightforward troubleshooting to narrow it down, just time and effort which would be saved by plugging an RS Tuner or CLIP or OBD in.

How sure are you the timing is right?

 

[Johnson.]

Thanks for the replies - Appreciated.

Pretty sure the timing is correct, used the correct tools from a garage who allowed use of his tools. Also, Im sure that if the timing was out, the misfire would be present at any rev range, not just below 3k ish ? Ive not been able to drive the car yet, just start it.

The airbox is completely off at the moment which isnt really fair on the car, so my first port of call when i finish work is to refit this and see where we go from there. Checked all the plugs before putting them back in and they all appeared to be fine, although looks can be deceiving. I will have a play later when i am home, but i was eager to get some answers so i posted on here.

Cheers,

Ben

 

[bloke]

why was it a non runner?

 

[Johnson.]

Cambelt had slipped and bent a few valves. New head put on along with new timing beltkit and cam seals.

Watch "Clio 172 misfire" on YouTube


Here is a video - poorly sick Car!

 

[Johnson.]

Changed lambda sensor this evening and the problem persists. The car is running rich and the lambda change doesnt appear to have made any difference. I cant see it being the timing myself, the car revs up to well. Seems to misfire when the car is kept at a constant rev range. Car is idling alot better now however if you gove the car a good blip of the throttle the car will often stall

 

[The Chubby Pirate]

I think you'd best describe the exact way you done the timing on this as they are very very sensitive to how they're set up (from what i've read..!)

 

[Johnson.]

I think you'd best describe the exact way you done the timing on this as they are very very sensitive to how they're set up (from what i've read..!)

Thanks for the reply... we followed the guide on the forum to do the timing and used the correct tools for the job. I just dont see how it can be the timing personally... over 3k ish revs there is no misfire. I would imagine if the timing was out the misfire would be apparent whatever revs ?

 

[The Chubby Pirate]

@Dan@SJM

 

[Dan@SJM]

The guide on the forum is incorrect for many reasons.

It can quite easily be timing, misfire at low revs is quite often a sign.

Back to basics.
Spark?
Fuel?
Compression?

 

[Johnson.]

The guide on the forum is incorrect for many reasons.

It can quite easily be timing, misfire at low revs is quite often a sign.

Back to basics.
Spark?
Fuel?
Compression?

Thanks for the reply.

Fuel, the car is running rich and throwing out clouds of black smoke out of the exhaust. Spark, we have 8 plugs in total, albeit used. Should probably try a new set although i am reluctant at £60+ VAT for a set! Im sure out of the 8 we have, 4 of them will be good enough. Compression, i will put a compreasion tester on it and see whats what. Interesting about the timing, when taking on this task i checked the forum for advice and alot of people reccomended the guide. TDC pin was used aswell as the tool for locking the cams off.

 

[Dan@SJM]

What about the pulley locking tool? Was the timing mark visible in the bell housing? Were they genuine Renault tools or the laser/AST equivalent?
What spark plugs are you running?

Also, it's only ~£45 for the plugs from Renault Wolverhampton.

 

[Andy93]

Road track race parts (George) do the plugs for £36 a set also.

 

[Johnson.]

We didnt use the pulley locking tool. I was under the impression that was only neccersary when changing the dephaser pulley. Tools were AST and borrowed from an ex renault technician, they are good enough for him so i opted to use these. Interesting point about the timing mark being visible in the bell housing, maybe this is where the issue lies. All 8 plugs are NGKR

Playing around with the car again this evening, the car has a dodgy idle and is only missing when kept at the same revs. It revs up fine with no issues.

 

[Ol’ Tarby]

So did you not loosen the pulleys off at all?

 

[Johnson.]

So did you not loosen the pulleys off at all?

Thats a good point... thinking about it we changed all of the cam seals and have actually had both of the pulleys off to do so. To tighten the bolts back up we locked the cams off to stop the pulleys from moving, Not with the same tool used to time the car back up may i add...

 

[Ol’ Tarby]

Did you then set the tensioner, and spin the belt round a few times with the cams still locked, but the pulleys loose?

 

[Johnson.]

I dont recall doing that no, guesing we should have done ?

 

[Johnson.]

Watch "172 misfire 2" on YouTube

 

[STEVE.M]

Untill you can confirm the compressions are all good,any replies are pure conjecture.Not to bang in a set of new plugs following a satisfactory compression test would be a false economy IMO.

 

[Ol’ Tarby]

If he didn't rotate the belt round a few times to even out the tension across the belt, then it'll probably be the timing

 

[The Chubby Pirate]

FFS @james24785 - never knew you knew that spanners just weren't for stirring tea with! Ha! :wink:

 

[Dan@SJM]

We didnt use the pulley locking tool. I was under the impression that was only neccersary when changing the dephaser pulley. Tools were AST and borrowed from an ex renault technician, they are good enough for him so i opted to use these. Interesting point about the timing mark being visible in the bell housing, maybe this is where the issue lies. All 8 plugs are NGKR

Playing around with the car again this evening, the car has a dodgy idle and is only missing when kept at the same revs. It revs up fine with no issues.

The tool is required all the time, as said above, you rotate the whole belt and pulleys with the cams and crank locked.

Just because he believes the AST ones are as good, they aren't. You look at any reputable specialist, we all use genuine Renault tools for a reason. You do the pulleys up without the tool and you're likely to bend the tool and damage the cams.

 

[Ol’ Tarby]

FFS @james24785 - never knew you knew that spanners just weren't for stirring tea with! Ha! :wink:

That's what screwdrivers are for

 

[Johnson.]

Thanks for the replies. Shall run a compression test this evening.

 

[Johnson.]

The tool is required all the time, as said above, you rotate the whole belt and pulleys with the cams and crank locked.

Just because he believes the AST ones are as good, they aren't. You look at any reputable specialist, we all use genuine Renault tools for a reason. You do the pulleys up without the tool and you're likely to bend the tool and damage the cams.

I apologise, I'm not sure I said or meant that he thinks they are as good as the Renault ones. He worked in a Renault workshop and has since opened up a garage of his own, he allowed me to borrow the tools to time the Clio back up which turned out to be the tools from AST. What I meant was if they are good enough for him, they will surely do the job I needed them for. I guess it is a matter of opinion, which coincidentally I have followed a lot of those from this forum and it would appear that to some degree I am being misguiding. Take the guide on fitting the cambelt kit for instance. Reading around, a lot of people have been pointed towards that very guide, yet somebody further up this thread said it is incorrect for many reasons. Who do you believe? In no way a dig as I have found the forum to be very informative and a lot of the people that make up the forum have been very helpful.

May I ask why it is neccersary to rotate the whole belt? If it is to make sure that the tensioner is seated correctly then I am satisfied that it is/was.

Thanks again for the replies

 

[Ol’ Tarby]

May I ask why it is neccersary to rotate the whole belt? If it is to make sure that the tensioner is seated correctly then I am satisfied that it is/was.

Because the tension needs to be evened out across the whole length of the belt. Otherwise, the only bit you have tensioned is the bit of belt between the tensioner and the cam. If the cams aren't locked then as the tension evens out, they drift out of time.

Someone else might be able to explain it better than me, but basically, you need to do it, and do it first before you waste your time trying anything else.

 

[bozothenutter]

The guide on the forum is incorrect for many reasons.

It can quite easily be timing, misfire at low revs is quite often a sign.

Back to basics.
Spark?
Fuel?
Compression?

then why is the guide still up?
one for the mods I guess

 

[Ol’ Tarby]

then why is the guide still up?
one for the mods I guess

I'll have a look into it later, and see if Dan (or anyone else) would be kind enough to correct the misleading parts

 

[Johnson.]

Because the tension needs to be evened out across the whole length of the belt. Otherwise, the only bit you have tensioned is the bit of belt between the tensioner and the cam. If the cams aren't locked then as the tension evens out, they drift out of time.

Someone else might be able to explain it better than me, but basically, you need to do it, and do it first before you waste your time trying anything else.

Thank you James, appreaciate that.

 

[Dan@SJM]

I apologise, I'm not sure I said or meant that he thinks they are as good as the Renault ones. He worked in a Renault workshop and has since opened up a garage of his own, he allowed me to borrow the tools to time the Clio back up which turned out to be the tools from AST. What I meant was if they are good enough for him, they will surely do the job I needed them for. I guess it is a matter of opinion, which coincidentally I have followed a lot of those from this forum and it would appear that to some degree I am being misguiding. Take the guide on fitting the cambelt kit for instance. Reading around, a lot of people have been pointed towards that very guide, yet somebody further up this thread said it is incorrect for many reasons. Who do you believe? In no way a dig as I have found the forum to be very informative and a lot of the people that make up the forum have been very helpful.

May I ask why it is neccersary to rotate the whole belt? If it is to make sure that the tensioner is seated correctly then I am satisfied that it is/was.

Thanks again for the replies :smile:

You implied that if he uses them, he believes they are as good as the Renault ones is what I was getting at. They simply aren't.

Several people who have pointed towards the guide, yet none of them do these day in day out? Again, up to you who you want to believe.

I'll have a look at the guide later on if I have time, but sadly paying work and family time comes first.

 

[Johnson.]

You implied that if he uses them, he believes they are as good as the Renault ones is what I was getting at. They simply aren't.

Several people who have pointed towards the guide, yet none of them do these day in day out? Again, up to you who you want to believe.

I'll have a look at the guide later on if I have time, but sadly paying work and family time comes first.

You must have understood, I wasn't implying that as I can't speak for him. I was implying that if it is good enough for him then it is good enough for me... he uses them on a daily basis I don't.

I didn't say I don't believe you, I have no doubt about your knowledge or ability and i thank you for your constructive replies. I'm sure if you wanted to help improve that guide you would have done so by now, not good for business though perhaps? I chose to give it ago myself as opposed to paying to have the work carried out and searched the forum for some information. In doing so, I came across the guide and decided to follow it. I am aware that some things on these forums are to be taken with a pinch of salt, but if you don't have a bit of faith in this kind of information what is the point of these forums ? Apart from touting for business of course. You've just said that paying work and family time comes first ( I'm sure we all share this opinion however I don't feel sad about it ) so what is the alternative?

 

[Dan@SJM]

I don't even tout for business now, I've no need.

But anyway, I've given advice on what to check, if you choose to ignore, that's your choice. im far too busy to spend hours giving tech support all day every day, let alone going through all the guides to correct them. On that note, I'm out.

 

[STEVE.M]

I don't even tout for business now, I've no need.

But anyway, I've given advice on what to check, if you choose to ignore, that's your choice. im far too busy to spend hours giving tech support all day every day, let alone going through all the guides to correct them. On that note, I'm out.

 

[STEVE.M]

As usual on CS,it`s the omissions that tell the real story.Good engines come up for sale quite often.
All singing,all dancincing cylinder heads?You tell me when you last saw one!

 

[Johnson.]

I don't even tout for business now, I've no need.

But anyway, I've given advice on what to check, if you choose to ignore, that's your choice. im far too busy to spend hours giving tech support all day every day, let alone going through all the guides to correct them. On that note, I'm out.

Jolly good for you. Certainly have not ignored you either. I went back to basics long before I posted the thread asking for advice, and I am working my way back through them as and when I can. Thanks for your input so far and all the best.

 

[Johnson.]

Can anybody identify what this is and what it does ? Because this one doesnt appear to do a great deal.

 

[Johnson.]

Im thinking this pipe may have something to do with my issue. If you let tghe car get up to temperaryre, ( roughly half way on the gauge ) and pull off this pipe and put it back on, the car runs sweet. No misfire, no bad idle - nothing. Not the bed picture admitedly, but it sits on the back of the throttle body and the pipe disappears somewhere behind the sound deadening on the bulk head.