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Really feint hesitation/miss at light throttle



Pegasaurus Rex

Bon Jovi Officianado
ClioSport Club Member
Yeah I’m not sure I’m a great example to anyone 😂 basically I’m a pathetic quitter! Who’s answer to resolving a problem is dropping money, throwing a hissy and sacking something off. For me though it was absolutely the right call. I was never going to get my old car to a position I was happy with and I had far, far more problems to address than the OP.
 

Martin_172

ClioSport Club Member
The rear O2 sensor keeps being mentioned, don't worry about it, it's not controlling anything. The cat will be fucked after years of this too. But if it's pulling fine up the revs it won't be doing any harm or causing the issue, it's just not doing its job and killing the butterfly's!

I've come across this problem a few times and it's almost always the front lambda sensor, don't assume the new one is ok as that can take you on a wild goose chase round every sensor and piece of wiring.

Get yourself to euro and get a genuine Bosch sensor, if it doesn't cure it, return it.

I would also be checking the white connector under the engine bay fuse box. It causes mayhem when it's not behaving.

This will be an easy problem to cure, your looking too much into it, think logical, start fresh with it.

People will say take it to a specialist and that is a great idea if you have one local who's good (which you said you don't) so at the end of the day it's a 20yr old 4cyl engine, it's not complicated. I've pulled my hair out with them in the past but just look at it with a clean head and don't assume the new parts are all ok
 
  2003 Clio 172
love this post Martin.........motivated me......thanks :)

yep, genuine bosch o2 went in but will replace as has been said. looking back, it's a year old now......service item almost imo.

I went to town on the white connector under the bonnet. cleaned, inspected and repeated several times, will do so again tho

oh yea, and fk the butterflies lol
 

Touring_Rob

ClioSport Club Member
I think from input here it behaves just like a binary check to verify the cat is working but that might be wrong

My understanding is this. The rear lambda on these cars does not have an effect on fuel trim (short or long) and is there as a check catalytic efficiency. You can unscrew the rear lambda and cable tie it out the way, replace it with a bung and still not have a CEL.

I will look through some logs I have on another engine, close to 100kPa is a natural reading for a normally aspirated engine at sea level, 55kPa seems a little high at idle which might suggest a vacuum leak.

The air temperature sensor will also have a large impact on fueling.

out of curiosity what is your MPG like?

Your data from the fuel app looks wrong(ish). My understanding is that you should be getting a consistent voltage of between 0.1 and 0.6ish from the post cat narrow band lambda while yours seems high (rich) all of the time other than when you give what I assume is a throttle blip.

Ignoring that, I can see a huge lean section on both sensors, I assume this is from a decent throttle stab? Looks way too long (time wise). Its almoust as if the ecu has totally missed the enrichment event, does your fuel datalog map and tps readings also, they would be interesting to look at, both against O2.

Apologies if you have said this already, but after a large throttle stab does the idle take a long time to settle again?
 

Touring_Rob

ClioSport Club Member
My understanding is this. The rear lambda on these cars does not have an effect on fuel trim (short or long) and is there as a check catalytic efficiency. You can unscrew the rear lambda and cable tie it out the way, replace it with a bung and still not have a CEL.

I will look through some logs I have on another engine, close to 100kPa is a natural reading for a normally aspirated engine at sea level, 55kPa seems a little high at idle which might suggest a vacuum leak.

The air temperature sensor will also have a large impact on fueling.

out of curiosity what is your MPG like?

Your data from the fuel app looks wrong(ish). My understanding is that you should be getting a consistent voltage of between 0.1 and 0.6ish from the post cat narrow band lambda while yours seems high (rich) all of the time other than when you give what I assume is a throttle blip.

Ignoring that, I can see a huge lean section on both sensors, I assume this is from a decent throttle stab? Looks way too long (time wise). Its almoust as if the ecu has totally missed the enrichment event, does your fuel datalog map and tps readings also, they would be interesting to look at, both against O2.

Apologies if you have said this already, but after a large throttle stab does the idle take a long time to settle again?

EDIT* didn't see Martins reply, good advice from him there.
 

Touring_Rob

ClioSport Club Member
Last passing thought is that if the car is considerably better after having the battery off for a while, the fuel trims will have likely reset - this may well also point to the primary lambda as being the (or part of) the issue. I've had a car before where the primary lambda had degraded over time, the long term fuel trims would gently go to pot over a few hundred miles.
 
  2003 Clio 172
My understanding is this. The rear lambda on these cars does not have an effect on fuel trim (short or long) and is there as a check catalytic efficiency. You can unscrew the rear lambda and cable tie it out the way, replace it with a bung and still not have a CEL.

I will look through some logs I have on another engine, close to 100kPa is a natural reading for a normally aspirated engine at sea level, 55kPa seems a little high at idle which might suggest a vacuum leak.

The air temperature sensor will also have a large impact on fueling.

out of curiosity what is your MPG like?

Your data from the fuel app looks wrong(ish). My understanding is that you should be getting a consistent voltage of between 0.1 and 0.6ish from the post cat narrow band lambda while yours seems high (rich) all of the time other than when you give what I assume is a throttle blip.

Ignoring that, I can see a huge lean section on both sensors, I assume this is from a decent throttle stab? Looks way too long (time wise). Its almoust as if the ecu has totally missed the enrichment event, does your fuel datalog map and tps readings also, they would be interesting to look at, both against O2.

Apologies if you have said this already, but after a large throttle stab does the idle take a long time to settle again?

I was also told by Fred on here that if I was seeing 40mpg and 60mph in 5th then I wasn't far off good and that is what I am seeing at the moment in that scenario

Daily driving however it's sitting around 26/27mpg.

Air temp sensor hasn't been replaced but I think i can pull live data for that as well.

And with regards to the data I uploaded, it's probably too long for me to recall the exact scenarios so I might do some logging where i note the time stamp for a WOT run and a casual pull.

Cheers guys, appreciate the input

J
 

Louis

I Park Like a C**t
ClioSport Club Member
I was also told by Fred on here that if I was seeing 40mpg and 60mph in 5th then I wasn't far off good and that is what I am seeing at the moment in that scenario

Daily driving however it's sitting around 26/27mpg.

Air temp sensor hasn't been replaced but I think i can pull live data for that as well.

And with regards to the data I uploaded, it's probably too long for me to recall the exact scenarios so I might do some logging where i note the time stamp for a WOT run and a casual pull.

Cheers guys, appreciate the input

J
That's normal mpg for daily driving.
 
  2003 Clio 172
OK, grabbed a few logs. Will upload when home.

interesting that after the battery pulled last night, it is pulling like an absolute unit.

rear o2 was showing a historic error at start which I cleared.

it was there after the runs with no cel thrown.

rear o2 was around 400 before the spirited runs, near 600 or 700 after
 
  2003 Clio 172
Actually, these are RSTuner logs which I am assuming that not all of you will be able to open?

Perhaps I can just screen capture them as videos or the points that i might feel of interest. Leave it with me.

As for screenshots

1600266590862.png


So I reset the codes and pulled the following with the engine off

1600266625713.png


Took it for a little blast and we were looking at the following

1600266663573.png


And hey presto, this was back

1600266690950.png
 
  2003 Clio 172
Here is a WOT run, 1st and 2nd to limiter pulling on to motorway

 
  2003 Clio 172
right..... my mega seal between the cat and mid section (after both o2 sensors) was less than mega. blowing out at the top. sorted that.

also had a goosey at the rear of the cat and it is perfect. fine mesh, no damage and no blockages

:/
 

Touring_Rob

ClioSport Club Member
Joke - nothing stood out to me as being awful however I am not used to looking at logs with a narrow band sensor. I would be swapping the front lambda sensor out for a genuine one and having another look to see if there are any vac leaks, under inlet, injector O-rings, servo pipe etc. your spray test was good, better off using propane or finding a garage with a smoke tester (buying a cheap smoke tester).
 

Touring_Rob

ClioSport Club Member
Only thing that possibly stands out is your primary lambda does seem a little slow to respond, which for me would be another reason to swap it. I can see both going full lean on the over run with fuel cut which is good. Sensor should be transitioning from rich to lean in better than 100ms.

A good way to check this is to take a data log at idle and pull a vac line off the engine. Engine should go lean and in your logs you can measure the response time of the sensor.

It is possible that you have the wrong part installed giving iffy readyings overall. Or a vac leak, would be handy for someone else with an RS Tuner to share their long term fuel trim also and other general readings.

Did you look into your throttle body any more?
 
  2003 Clio 172
So yeah

This is still happening........lol

New plug leads didn't change a thing at all and granted, they were not genuine reno parts but they were at least NGK.

Once the car is up to speed (engine speed) there isn't a sniff of hesitation though. It's always low down and splutters like a pig, clutch in, quick rev and away you go. Worst when in too high a gear for example but does happen in 2nd or 1st if I am slow enough.

Tangent thought, could this be an alternator issue? I only ask as when I rev i notice the lights in the car initially dimming before it picks up. I also have one of those wee ultimate speed battery chargers that checks the alternator and when running it is saying 60. 60 whats.........I dont know but 60, not 100. lol. I will look into what that reading ACTUALLY is.

Haven't thrown any more parts at the car as have not been well lately but given we are all hanging about now I am putting more thought into it.

And sorry @Touring_Rob haven't looked into the things you mentioned. Top of my list.

J
 

MonkeyKnifeFight

ClioSport Club Member
  Rusty Cup
Mine had the hesitation at cruising speeds. I noticed the vvt solenoid was leaking so fixed that with plumbers tape and at the same time swapped out the throttle body as i had a spare sat around. Havent had the hesitation since.

I think i still have my old throttle body i could put it back on this weekend to see if the hesitation comes back if you like?
 
  2003 Clio 172
I am leaning towards it not being the throttle body tbh as it has been doing it worse recently, it has a very distinct fuel or ignition feel.

I have been in cars off a cylinder which still pull albeit slowly and given that, this almost feels like its off 2.

am I right in saying that this is a wasted spark dual coil setup? I.e. a faulty coil would kill 2 cylinders?

could my new coil be junk?
 
  2003 Clio 172
Hello :)



Yeah. Still happening. I know. I KNOW!

Well, lots has been going on personally so just have not had the effort to throw at this until lately.

One thing that did happen was the battery, out of the blue, all of a sudden. Just. Died.

Literally arrived at mums after a 15 minute drive from the shops, hopped out to give her some groceries and back in literally about a minute after. Nothing. Threw on a charger. Nothing. Threw on a booster. Nothing.

Even checking the voltage on the battery it was actually all over the place, I have never seen that.

Anyway, threw a new battery on and up she spun. It did have a little wobble with the immobilizer for a minute or 2 after the battery was replaced (solid light), again , never seen that before but might just have been the nature of how it failed or something? Anyway, that went away on the second or 3rd attempt at a start. Weird.

I guess I did have some symptoms of this prior such as the trip computer resetting and things like that. I have also noticed that since the new battery went in, I have had 0 rear O2 sensor failures randomly reported.

Also, an interesting observation and one that I hope doesn't sound crazy. But since the new battery went in..............the car smells different. I mean the exhaust etc and the smell of the car when it gets a horsing. Interesting right? So I am almost sure it was affecting running.



So, back at the task.



I am almost resigning myself to stop chasing this and just live with it which is a bit sad having owned the car for over 10 years now and muggling through most things, even the scary stuff (to me) such as the timing myself :(

To further update my efforts, I brought the car to a local indy who came well recommended (from an auto electrics and general gremlins pov) to see what his thoughts were. Told me timing. Definitely timing.

I then brought it to Renault (one out in the country as our closest is, well........useless). Paid for the diagnostics and they told me nothing was coming back as having any issues (I did blow all the errors away as there were MANY after the battery issue) but when I asked them about the hesitation they told me they are like that. I advised how long I have owned it and it did not do this in my first years of ownership, they then suggested............timing.

Ok, so, bought 2 new cam plugs and reluctantly spent a Saturday afternoon checking this again. Bear in mind, I checked this last year so these guys put doubt in my head that it could have slipped or something.

No. Perfect. Couldn't be any more perfect. The exact same experience as when I last checked it where the cam tool just slides in like butter.

I also checked the crank locking position using a bore scope (got bless Lidl) that I got a wee while ago and was worried that perhaps, had I missed the correct spot all those times? No, perfect. Sitting in the little notch in the crank.





So here we are again. :/

Parts cannon has NOT been pulled, just can't afford it.

Latest observations, I don't know if it might help or not.

On start up, at slight throttle..........the car is brutally off a/some cylinders.......sounds 2cv like and the stench of petrol is unreal. After a short while this goes and while I haven't actually checked, I am pretty sure this is when it is in open loop and when it switches to closed loop this disappears.

It categorically, did not do this previously.

So, going down that avenue, if it is displaying an issue in open loop, am I right in assuming that this rules out the O2 sensor? (which has been changed oh so many times with zero effect on this issue). What sensors are in use in open loop? Intake temp, map, coolant temp, tps, knock etc?

As I say, I know they are lumpy but this is top fuel lumpy.



Other musings.

Reverted to old injectors. Zero change until one actually failed and threw the light. Back to new ones.

Reverted to old coil pack. Confirmed coil pack issue with old one which is a much sharper feeling misfire than this. Back to new coil.

Reverted to old plug leads. Zero change.

Pulled the plugs. Completely fouled with soot as one would expect. Cleaned and popped back in as they are nearly new.

Pulled the O2 sensor. Completely fouled with soot as one would expect. Cleaned and popped back in as again, nearly new.

Have not touched the TB at all

Have not replaced the intake temp sensor

Have not replaced the map sensor

Replaced the inlet manifold donut gasket last year

Replaced the knock sensor wayyyyyyyyyyyyy back at the start of ownership.

Replaced the thermostat and water temp sensor maybe last year

New O2 sensor last year

New plugs last year

New fuel filter (yes, external one under the rear of the car) maybe 3 years ago



So, would appreciate a new steer and a fresh angle if I am going to even try sorting this.

J
 

Louis

I Park Like a C**t
ClioSport Club Member
If it has to come to that, it's not worth it.
It's been nearly 4 years. Just go on holiday to the UK for a week and drop the car off at a specialist. Likes of mick at diamond would find it easily.

Then drive the car back home again. Just a no-brainer
 

leedsboy

ClioSport Club Member
  Bean 182 + E70 X5
It's been nearly 4 years. Just go on holiday to the UK for a week and drop the car off at a specialist. Likes of mick at diamond would find it easily.

Then drive the car back home again. Just a no-brainer
This x762.

Either just drive it and make do (like surely it can't be that bad can it?) or just bite the bullet and travel to Mick for it sorting.
 
I've read this thread from start to finish. Came up on Google search as mine has just started exhibiting some of the symptoms you've had.

One of the things I've noticed you haven't done is a compression test. Get a decent gauge though - the cheap red box Chinese ones are awfully off. Gunson is a reasonable brand. Also leak down test is a useful thing too if you have a compressor.

Another thing, I noticed you said you're not on a stock map. Have you tried a stock map again?
 

Touring_Rob

ClioSport Club Member
I've read this thread from start to finish. Came up on Google search as mine has just started exhibiting some of the symptoms you've had.

One of the things I've noticed you haven't done is a compression test. Get a decent gauge though - the cheap red box Chinese ones are awfully off. Gunson is a reasonable brand. Also leak down test is a useful thing too if you have a compressor.

Another thing, I noticed you said you're not on a stock map. Have you tried a stock map again?
He's done mate, assuming he set fire to it late Wednesday night.
 


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