ClioSport.net

Register a free account today to become a member!
Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Really feint hesitation/miss at light throttle



  2003 Clio 172
Thanks Martin, fair point.

It does occur to me that this TB did have a *moment* in the past with me pressure washing the engine. It had a hissy fit then but fixed itself.

Fair to assume that water may have got in and be causing havoc now perhaps.

On that note, anyone have a known good tb for sale?
 

Mbeau

ClioSport Club Member
  Clio 172
Thanks Martin, fair point.

It does occur to me that this TB did have a *moment* in the past with me pressure washing the engine. It had a hissy fit then but fixed itself.

Fair to assume that water may have got in and be causing havoc now perhaps.

On that note, anyone have a known good tb for sale?
I have a couple of good spare ones for sale.
 

Amos91

ClioSport Club Member
I haven't buddy. Do you think the 50-72 value from torque (if correct) is a bit amiss?
Coolant temp only got to 72C?

it should be getting up to about 87C and the thermostat will then open and keep it around there. Replace the thermostat / cts.

Torque is accurate for coolant temps.
 
  2003 Clio 172
ok ok ok

I haven't got to the CTS or thermo yet.............have been moving house but made an observation at the weekend that might have been touched on and not sure if relevant

Between the storms, I was taking the littl'un to hockey practice..........was quite still and I had the window down

I am 99% sure I heard a hissing building up as I was driving that didn't drop in line with revs ( I was thinking pulley hiss ) but instead, faded away

This was most notable in second gear where you arent really going too fast for road noise to drown out the hiss but the revs are high enough

So, I haven't been able to start pulling stuff apart yet, but could a partially blocked CAT be doing all of this?

I would have thought the car would be really dead if that was the case but it does go



I am just thinking that all the injector and coil issues of the past year might have knackered or melted some of the cat and if it is blocked, could this be causing the over fuelling etc

Means nothing without investigation I know but just wanted to sound it out

J
 
  2003 Clio 172
would the car still go alright with a collapsed/blocked cat though? low down it is pish but when you get up the revs its away
 

MRBILLYUK

ClioSport Club Member
  FF Jeden Osiem Dwa
would the car still go alright with a collapsed/blocked cat though? low down it is pish but when you get up the revs its away
I've seen people who had a blocked Cat saying they are lacking power. Not sure if that's the problem you're having as ya say , higher revs and its ok.
I guess the only way to tell is if you can get your hands on another Cat just to try or even a decat.
 
Last edited:
  2003 Clio 172
Right, today was the first time I had a normal drive in the car (school run on country roads and then into traffic on the motorway)

So, bearing in mind it was about 1 degree here

After the car was warmed, say 20 minutes of driving..........the coolant was showing as being 73

Sitting in traffic on the motorway it got to around 81 but once i was driving it quickly dropped to around 76

This is the first time i have noticed the needle actually go down on the dash, was always used to a rock solid horizontal needle, it never went down afaik.


So going to replace the stat and cts as advised.


Next, can anyone confirm who has an obd tool and torque or similar, if your downstream cat value moves?


Mine is literally all over the show and i thought that should be fairly static?

Upstream is doing its up/down thing so looks fine but again. i never recall the downstream moving so much. To clarify, once the car was up to temperature (seemingly) I have downstream values ranging from 0.02V to 0.94V

This was towards the end of a 1 hour drive

1582712049190.png


Blue is the coolant
Orange is the seemingly fine upstream O2
Gray is the downstream O2

As you can see, I am now pursuing the stuck stat, faulty cts and broken cat approach and just wanted to sound the above out

J
 
  2003 Clio 172
Ok......cts and thermo replaced with genuine stuff. Car gets up to about 88 / 90 or so quickly and stays there like a rock.

As per previous thermo related threads, internal rubber was perished so i guess it was open all the time to a degree.

Still no difference in running and despite my previous comments, I am starting to think it is actually holding back up top.

A quick blast to get air out of the system earlier and I swear to god 3rd gear felt like it was taking an age to rev out up top.

Huge buzzing and singing from cat and back box areas of exhaust. This also might be related to the exhaust sounding like it's getting very hot. Exhaust cracks and pops for ages after any kind of drive.

Really starting to lean towards a blockage somewhere now

Could the injectors/coil being duff for a period of time have melted the cat and partially blocked it?
 

Louis

ClioSport Club Member
Sounds better on the temperature front. I'd definitely be taking the cat off and having a look. Pain on a 172 but not as bad as a 225 meg.
 
  2003 Clio 172
Right.............I am still here and this thread is still a thing. Sorry guys.

Over the lock down, I was able to do a bit of investigation work. I pulled the front lambda out and popped in a borescope..........cat looks spot on (well, the grid is perfectly intact and i thought collapsed cats would look nuked)

The front lambda was pure soot

Car still bogging down/hesitating when hot or cold, doesn't matter

I am still quite adamant that I hear a hiss from the engine which rises with engine speed and load and I was wondering, are the pipes at the servo a point of failure. I have inspected everything that I can get to readily and do not see any leaks but the servo is kinda out of the way
 
  2003 Clio 172
Hi gang,,,,,,,,,,,,,,,,,,,,,,,,,its meeeeeeeeeeeeeeeeeeeeeeee

So, still happening.


Threw a little set of NGK plug leads at the car to see if it would help and nothing changed at all, not better, not worse.

Still randomly bogging right down. Say, pulling away in first gear and let the revs bumble a little low and the car behaves like its on 2 cylinders, clutch in, quick rev, try again and off you go.

Still has the hesitation when coming on throttle.

What I have noted every time I have went into RSTuner of late is that the rear O2 is being flagged as a historic error. So it has grumbled at some stage between being on the diagnostic. We are talking maybe at least once a week that error must be getting thrown.

Sometimes, i get a light, go into RSTuner and the rear O2 is showing as a historic (not current) error again.

halp
 

Touring_Rob

ClioSport Club Member
  182, E46 M3, 1000RR
Did you check for vac leaks? You mentioned a hiss, would be useful to check that out. This is a speed density car so vac leaks will cause big headaches.

Did you swap lambdas or change the primary lambda?

Injectors seem to be a common failure recently, one of mine failed and made mixture very rich, could explain soot on lambda, does the car smell badly of egg when accelerating?

What does RS tuner report your MAP Kpa, Air temp and Coolant temp to be?

Rob,
 
  2003 Clio 172
Hi guys,

Cheers for the suggestions @Touring_Rob

Ok, i checked for vac leaks with brake cleaner......lol........not scientific I know but all i knew to do. Noticed no change and I gave it a good dosing around gaskets, servo etc.

The injectors were all replaced with brand new when i originally had a go at this, no change

I swapped out the secondary lambda with one that I had lying about (that was ironically also removed to try and fix this) no change again.

And I have noticed an eggy smell every now and then but not all the time. I remember the old mans car lost a cat and everything stank of eggs all the time. Was bouncing. It isn't like that.

The way it behaves, now.........this might sound dumb. It almost feels like too much fuel is going in. Driving it today, when I come off the gas completely, the engine feels like it is still on the gas slightly.......and after a bit it starts to slow down like the pedal has been released. I know that sounds gobbly, sorry.

It is still twatting out big bangs when the engine is hot on overrun and this car does not have the pops and bangs map. I would say however, it sounds more like a hot hatch should though in this regard, only very occasionally producing a bang.

I did swap map sensors with Simon on here and noted no difference in value or operation, i think my figures were in spec but will check tonight

One final observation yesterday when I was checking for codes (again and again) was that in a live data view, the rear lambda value was very high, circa 1400 or something. Going to do a live data grab tonight to see if I can catch it doing the chuggy low rpm hesitation. Will see how successful that is.

Cheers again

J
 

Touring_Rob

ClioSport Club Member
  182, E46 M3, 1000RR
Ok, good going. Changing the rear lambda will not effect fueling - you need to switch out the primary lambda.
 
  2003 Clio 172
Eugh, thought I was on to a different line of possibility................noted the coolant dropping and was starting to lean towards a dying hg.

Nah.

Heater matrix.

Smelt coolant in the car and front carpets damp and sticky (good old Type D). Bright green traces under the interior fan housing.



Jesus. Actual. Holy. Bible.Christ.


Someone tell me this is not a complete bell end to do.

:/
 
  BG 182FF
Eugh, thought I was on to a different line of possibility................noted the coolant dropping and was starting to lean towards a dying hg.

Nah.

Heater matrix.

Smelt coolant in the car and front carpets damp and sticky (good old Type D). Bright green traces under the interior fan housing.



Jesus. Actual. Holy. Bible.Christ.


Someone tell me this is not a complete bell end to do.

:/
Have you ever thought of selling this car and buying a working replacement.
There not expensive.
 
  2003 Clio 172
sorry, maybe that seemed like a harsh reply but the comment annoyed me tbh

I have had this car for over 10 years now and have learnt most things inside and out (not the gearbox, no.....not that) and continue to do so and very much enjoy working on it

why on earth would I swap it for a car that could need the same if not more done when I know exactly what has been done to this car?

said it before, not a comment for an enthusiasts forum. maybe if an owner was not hands on like me then perhaps yes......but you can see that over years over ownership I have done a lot......including buying genuine timing tools and learning how to fix "specialists" mistakes with timing which is a huge problem on these.

all with the help of this forum and asking questions

surely, that is how this works?
 

Rojer

ClioSport Club Member
  Civic
sorry, maybe that seemed like a harsh reply but the comment annoyed me tbh

I have had this car for over 10 years now and have learnt most things inside and out (not the gearbox, no.....not that) and continue to do so and very much enjoy working on it

why on earth would I swap it for a car that could need the same if not more done when I know exactly what has been done to this car?

said it before, not a comment for an enthusiasts forum. maybe if an owner was not hands on like me then perhaps yes......but you can see that over years over ownership I have done a lot......including buying genuine timing tools and learning how to fix "specialists" mistakes with timing which is a huge problem on these.

all with the help of this forum and asking questions

surely, that is how this works?
I don't think the comment was meant in a nasty way, sometimes when you have a lot of issues with a car, you can end up cutting your losses and drawing the line and getting rid.
 

Touring_Rob

ClioSport Club Member
  182, E46 M3, 1000RR
I don't think they were trying to offend mate. Its possibly because your approach to fixing the original issue has taken some fairly odd turns and you don't seem to have gotten anywhere.

Like you think its the cat, so temporarily install a decat pipe
Change the front lambda not the back
Buy a vac leak tester and test for vacuum leaks properly

Bad news about your heater matrix, can only assume they are a but of a nightmare to change. I would start by pulling the bottom of the dash apart, my partners Citroen developed an interior leak which turned out to be an Oring on one of the pipes going to the matrix rather than the matrix its self.
 
  2003 Clio 172
looking back @Touring_Rob both front and rear o2 sensors were replaced with new less than year ago.

dont want to go down the route of replacing the cat, especially not with a decat. I don't want more noise or mot grief. besides, put it on a friends co meter and it was breathing air more or less as it always has.

so whatever happens, I think it happens randomly, stinks the cat, causes poor running and makes the rear o2 throw an error, possibly related to the cat getting smelly

and fwiw......the car had the battery disconnected for ages last night while I was replacing the thumb grips (airbag out etc) and before I noticed the damp and I swear it is running better today. Still missing or hesitating slightly upon take up but when it gets past that it is rapid. Simon will testify to that.

j
 
  2003 Clio 172
I also don't think I have taken odd turns.........I have logged other issues in here yes as I have worked on the car.......but I have followed the default cliosport guidance in terms of what was done.........injectors, ignition and timing.......that is pretty much a default reply for any poor running thread and I have done them with no change to this particular issue.
 

Touring_Rob

ClioSport Club Member
  182, E46 M3, 1000RR
Mine would run better after the battery was off when the lambda was failed. I think the long term fuel trim gets reset.

Not suggesting that you dump the cat for ever - but you keep mentioning a blocked catalyst, in which case grab a £20 decat pipe when one comes up for sale. Install it (not hard) and see if its better. If yes, find replacement cat, if no reinstall catalyst and continue.

Your fault finding methods seem to be pretty random tbh, perhaps that was the reason for suggesting you sell it.

Anyway good luck.
 

Rojer

ClioSport Club Member
  Civic
OK so i won't lie, i haven't read the entire thread so apologies if i repeat advise that has been said before. Do you have a code reader or access to one that can show you live data?

If so, plug it in and look at the o2 sensor readings. If the rear one is jumping all over the place and not at a steady low voltage reading then bin it. The primary should move and read higher, but confirm it's within spec. If you have an infrared temp gauge, point it at the front of the CAT and rear of the CAT to compare temp readings, if the rear is significantly cooler, then it might not be doing it's job. The exhaust gaskets for the CAT are notoriously rubbish and will leak, so buy a genuine gasket set, they are about £20 on eBay last time i checked. While its off look inside the CAT to see if it has come apart or blocked.

If you have replaced the injectors then that's good, but its not unheard of for the wiring to the injectors to go back so worth a check.

You have checked timing and VAC leaks, but i would also be checking the readings of the other sensors with the code reader. I had issues with the crank sensor on mine.

Realistically you wont find the issue without live data and some logs unless there is blatant error codes.
 

Touring_Rob

ClioSport Club Member
  182, E46 M3, 1000RR
OK so i won't lie, i haven't read the entire thread so apologies if i repeat advise that has been said before. Do you have a code reader or access to one that can show you live data?

If so, plug it in and look at the o2 sensor readings. If the rear one is jumping all over the place and not at a steady low voltage reading then bin it. The primary should move and read higher, but confirm it's within spec. If you have an infrared temp gauge, point it at the front of the CAT and rear of the CAT to compare temp readings, if the rear is significantly cooler, then it might not be doing it's job. The exhaust gaskets for the CAT are notoriously rubbish and will leak, so buy a genuine gasket set, they are about £20 on eBay last time i checked. While its off look inside the CAT to see if it has come apart or blocked.

If you have replaced the injectors then that's good, but its not unheard of for the wiring to the injectors to go back so worth a check.

You have checked timing and VAC leaks, but i would also be checking the readings of the other sensors with the code reader. I had issues with the crank sensor on mine.

Realistically you wont find the issue without live data and some logs unless there is blatant error codes.
🙌

Also heard of a few people who have bought knock off injectors which have either performed badly or have failed quickly. A damaged injector seal can create an annoying to find vac leak.
 
  2003 Clio 172
@Touring_Rob I don't think it was random mate.............long winded yes but I think important to not that it's not the "standard" fix suggested and as mentioned, I have hit other hurdles that stopped progress such as the gearbox 'nading itself.

Thank you however for taking the time and trying, I do appreciate that.

Hey @Rojer thanks for that, some fair points.

I have both RStuner and Torque (with a generic ELM clone) and have provided live data output a few times. Of late, I have noted the rear O2 sensor only sits still at idle, when driving it goes for the moon or else to 0. All over the show. The front O2 shows the fairly consistent switching pattern. I snaffled a quick video of Torque (just as it was handy) and you can see circa 8 minutes of driving. (https://photos.app.goo.gl/eGcekW5oz43Sohoa8) however, you can skip to 2 minutes and see how things go. This was normal driving in traffic.

Temp sensor is a good one, I will do that asap.

Cat to mani gasket was replaced with the parts cannon at the start, I agree, they are junk and a pain to do on your own but it was done. Other gasket is basically fused with high temp sealant and remains so.

Used a bendy "up the bum" scope :D to check the cat.......the inside structure looks fine from the front with no damage or debris, a perfectly clean mesh type affair. Granted, I have never checked it from the back so might do that (r.i.p my awesome sealant seal)

Injectors were all replaced with brand new items from Renparts, all were new and sealed bar one which was the completely wrong type (detailed in this thread) but this was subsequently and quickly replaced by Renparts, brand new and sealed again. Will however eyeball the wiring.

MAP sensor was swapped with @Simon998 and we noted no change. Mine is currently reporting around 550KPa at idle and 1000 ish at WOT with the engine off.

Crank sensor and loom were both replaced with the parts cannon exercise upon advice here. No change.

When I get a minute, I will do a full RSTuner logging run again and convert that to video and share it. O2 (both), MAP, RPM, temps, advance, injector trims, voltage, throttle position..........is there anything else I could capture that might be of use? Hopefully the car will be a d1ck as usually when i do this it tries its best to behave.

And fyi, yeah, the heater matrix looks like a tool of a job to replace a 20 quid part ffs. But doable and with an easily visible outcome. Not like this.

Thanks

J
 

Rojer

ClioSport Club Member
  Civic
If the rear sensor is reading all over the place then it's junk. I have a similar issue with my GF's Corsa atm, however i have noticed she has an exhaust leak in between the primary and secondary sensors so i'm hoping that will fix it. I would assume if the rear one is junk and the readings are off it would let the ECU know and it would adjust fuelling and timing to suit?
 
  2003 Clio 172
you know......I might ask the forum friend Henk @ fastchip (lol) to see what his understanding of it is.

I mean, he just maps them out
 


Top