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Stuck LTFT clio172/182



  Clio 172 ph2 / bikes
Anyone have on thoughts in this one.

Currently my LTFT is stuck at -14. 06% and will not adjust regardless how its driven. Tried the common typical battery disconnect and discharge to no avail, even left it 12 hours.

STFT seems to operate as it should. At warm idle ranging from - 7 to +10, occasionally hits +16 and errring on the positive side, id assume its trying to correct LTFT.

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Story goes. Was experiencing intermittent cold clutch judder both on open and closed loop, clutch is about a year old valeo item and doubt its done 10k nor is it treated hard, noticed LTFT was down to - 20 to - 30 odd and adjusting itself a bit, diagnosed a lazy cheap chinese s1 lambda, replaced it with a known working 2nd hand twingo rs sensor, turns out its the same sensor with a different plug so spliced the old plug on. Car ran well for a day and then stft got erratic and ltft settled at -14.06. Began to clutch judder hot and cold more often. Discovered the whole bosch lambda sensors take a sample air reference through the cable thing and you cant solder or crimp them... Yup beathing cable... Sounds mental but its supported in the bosch literature. So ive since replaced the lambda with a new bosch one, genuine of course. Stft came into range albeit nearer positive side of spec, suspect its trying to correct the stuck high negative ltft. Replaced the chinese tdc sensor, car ran better but still same issues, replaced spark plugs as they werent the reccomended ngk ones. Other than a little bit of occasional clutch judder when cold the cars running strong.

Quite content with the readings im getting from the sensors, ive tried spare map, intake temp and coolant temp sensors just for arguments sake.

Spark plugs when i changed them showed to be slightly rich, even across all 4.

Warm compression test showed near 190psi across all 4

1 injector was an ohm low, wasnt concerned but replaced it with a spare. Spray looks good across the 4 however i Havent flow tested them.

02s1 pre cat is new and operating in range

02s2 post cat is pegged at - 100, think its dead but apperently they only control the eml light. No immediate reason for concern.

No exhaust leaks before precat lambda.

Only code thrown is for a slow heater in 02s2.

Had it going on 4 years, Its an 02' 172, 155k on the clocks,
Ported inlet manifold, ktec induction kit with new ramair filter, 182 exhaust, 2.25 decat to old 2.5 ktec 172 stealth. 98 ron rstuner map. Carbon canister removed. Cup ac delete setup, 20k since new dephaser and timing done. Heap of other things but not relevant to issue. No recent work prior to clutch judder issue. Only run on super and its not down to bad or e10 fuel.

The inconsistency of the intermittent judder issue suggests its fuelling related rather than mechanical to me. Cant feel ignition or fuel breakup throughout the rev range, its sharp, punchy and strong.

Next steps as i Cant test fuel pressure on the 172/182 easily is to be replace the fuel pump as its presumably done 155k and all 4 plugs read rich, meaning its not indicating a specific injector or ignition issue, then a throttle body.

Id just like to get the ltft cleared to see if it will start behaving itself to get a clearer picture of whats happening before wasting money blindly.

Using car scanner on android, a scannex obd2 adapter, im not trained on reading data but a have good understanding.

Open to suggestions but any info on clearing a stuck ltft would be massively appreciated.
 
  Clio 172 ph2 / bikes
Right just following this up.

Was getting some poor stft readings and Ltft wouldnt adjust as mentioned above. This was on two different bluetooth obd tools and apps, tested on the rs tuner box via laptop too. This was over a period of weeks and hundreds of miles of mixed driving. Just seemed like ltft was frozen.

What i wound up having to do was reinstate the same calibration of my map via my rs tuner box. This reset the ltft back to zero and its back acting reguarly, allowing me to actually read/diagnose with fuel trim.

This issue is a bit of an anomaly, its nothing to do with the 98ron rs map which ive had for years issue free and ive not heard of anyone else experiencing similar.

The issue causing high negative fuel trim seems to have been down to a few things causing the ecu to read unburnt oxygen and dump more fuel in: a cheap tdc sensor, non genuine lazy pre cat 02 sensor, not running the correct ngk plugs and an ht lead that was out of spec. Replaced the above one by one and each rendered a significant improvement to what was already a savage wee 172. Cars running so sharp, you wouldnt believe it was turning 156k.

Currently have a +5 ltft and stft is within the +/- 10% range erring to 0 to -7 generally at idle which is healthy enough, slight lumpy idle, noticed ive got a couple non genuine injectors so ive picked up a genuine used set cheap, hope that just wraps this up nicely.

Its been said thousands of times on here but seriously, dont buy the non genuine sensors / plugs etc, it might be a cheap fix but its not going to produce the same results and youll likely need to replace them much sooner.
 
  2002 Clio II Ph2 172
Glad you solved your problem.
Reading about all these 172/182's with high mileages still running well is very encouraging indeed since my 120k miles 172 ph2 is my daily driver. I find it well worth it keeping ignition and injection components in top shape. Had the very common injector issues roughly 2 years ago, replaced all four with Magnetti Marelli iwp42's, spark plugs are new also and genuine renault. Also, new cables and ignition coil. Preventative maintenance.
Excess unburnt fuel in cilinders, cat and oil is NOT healthy for a car.
If i buy non genuine, i never go for the cheaper parts, quite on the oposite.

Just a curiosity: who makes the genuine renault lambda sensors.. Bosch? Never replaced the ones on mine, and you never know when they might act up.. Genuine renault lambdas are a bit expensive are they not? Afordable if needed, but expensive compared to the rest.
 

Porl

ClioSport Club Member
Glad you solved your problem.
Reading about all these 172/182's with high mileages still running well is very encouraging indeed since my 120k miles 172 ph2 is my daily driver. I find it well worth it keeping ignition and injection components in top shape. Had the very common injector issues roughly 2 years ago, replaced all four with Magnetti Marelli iwp42's, spark plugs are new also and genuine renault. Also, new cables and ignition coil. Preventative maintenance.
Excess unburnt fuel in cilinders, cat and oil is NOT healthy for a car.
If i buy non genuine, i never go for the cheaper parts, quite on the oposite.

Just a curiosity: who makes the genuine renault lambda sensors.. Bosch? Never replaced the ones on mine, and you never know when they might act up.. Genuine renault lambdas are a bit expensive are they not? Afordable if needed, but expensive compared to the rest.
When I replaced my lambda's the other year all my research came back with the same answer, only use bosch ones!
 
  Clio 172 ph2 / bikes
Glad you solved your problem.
Reading about all these 172/182's with high mileages still running well is very encouraging indeed since my 120k miles 172 ph2 is my daily driver. I find it well worth it keeping ignition and injection components in top shape. Had the very common injector issues roughly 2 years ago, replaced all four with Magnetti Marelli iwp42's, spark plugs are new also and genuine renault. Also, new cables and ignition coil. Preventative maintenance.
Excess unburnt fuel in cilinders, cat and oil is NOT healthy for a car.
If i buy non genuine, i never go for the cheaper parts, quite on the oposite.

Just a curiosity: who makes the genuine renault lambda sensors.. Bosch? Never replaced the ones on mine, and you never know when they might act up.. Genuine renault lambdas are a bit expensive are they not? Afordable if needed, but expensive compared to the rest.
Thanks man, yeah spot on with all that. If youve got a performance oriented car its vital that you use the right parts and these clios have a reputation for being fussy.

Think i picked mines up on 125k 3 or so years, encountered the usual clio gripes but i think its been a well enough looked after car in its time, surprisingly compression tests are at the high end of spec on 156k miles, it burns oil at high revs but thats to be expected. Gearbox number 2 is sweet. No significant rust underneath but arches starting to bubble. Doesnt look or drive like its done significant miles, its tight and it rips. Considering low boost turboing the thing but im not sure yet.

Like porl said bosch for the 02 sensors. I'm still in shock over them "breathing" through the wire to take a reference air sample. Seems a bit far fetched.

Annoyingly the clutch judder has returned after a couple weeks. Still dont think its the clutch as its not that old, no pedal vibration and it acts up intermittently, all the mounts are poly and recent enough too. Need to try catch it on live data when its acting up.

Probably going to pick up a fuel pump just for arguments sake and if not i'll need to investigate idle control i think which is probably another throttle body on the ph2
 

SteveC_1879

ClioSport Club Member
  Clio 182
When I replaced my lambda's the other year all my research came back with the same answer, only use bosch ones!

Absolutely vouch for that. The cheap ones don’t seem to work well at all. I changed mine for a euro car parts special and the issues didn’t disappear so I launches the parts cannon at it and changed all sorts. Eventually got suggested to try a Bosch sensor and as if by magic it was perfect 🤦‍♂️
 


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