Bogging/misfire under load at 2-3k

[KaitlinE07]

Looking for advice if possible, my 197 always bogs out/misfires between 2-3k revs under load, slow acceleration seems to be okay. Doesn’t show anything when it’s plugged in and I’ve been told the map is sound, wondering if anyones experienced this or has any idea where to start?
TIA

 

[Usman]

This happened to me when I had my 197. Turned out to be plugs in the end. It also showed no codes and only misfired when giving it a good amount of throttle.

 

[Hairyned]

Also an issue with an aftermarket exhaust or decat apparently. Mine does the same.

 

[KaitlinE07]

Possibly to do with the post cat o2 sensor then? I’ve had plugs replaced recently seems to be one of those annoying faults

 

[Hairyned]

Mine developed when I had the exhaust changed to a 3" stainless with a single high flow cat. Potentially a backpressure issue. Have you checked for leaks?

 

[KaitlinE07]

I haven’t checked for leaks yet but will deffo do that! Thank you!

 

[turkie172]

First thing remove the plugs and see if they are the correct ones (NGK PFR7Z-TG) and check for water or oil contamination as well as flash over on the ceramic body. Keep the coil packs and plugs in the same order from the plug you can have a good guess which plugs are worst and most likely the coil packs are faulty I fixed a 2008 Clio with two faulty coil packs they don't show up on diagnostics or codes. I had the ability to swap coil packs from my car to find the problem and I was surprised that two coil packs were faulty. O2 sensors can cause a fault I did have at one time an effect similar to a rev limiter but at low RPM intermittently until I had the RS tuner running live data and it indicated a forward lambda short circuit but the fault was not stored and if the car was turned off and restarted all traces were gone.

Note: when removing the coil packs the small bolts that hold them should only be 8Nm but are prone to over tightening damaging threads and remember how the VVT solenoid sits on the coil pack on the timing belt side as the bolt holds both in.

 

[bedoef]

Possibly to do with the post cat o2 sensor then? I’ve had plugs replaced recently seems to be one of those annoying faults

Likely this is the issue. Swap the sensors around and try going for a drive see if that solves the issue.

 

[SimiRockStar]

I have the same problem right now... i get a "missfire" or something like that.. loss of power .. on 2-3k .. but only on Full Throttle... Tomorrow ..fingers crossed... i get the OEM plugs from Renault.. i work there.. now i have iridium plugs PFR7Z-TG .... i hope this fixes the issue... searching for this fix for a long long time.. fingers crossed that the plugs will sorted all out..

 

[KaitlinE07]

I have the same problem right now... i get a "missfire" or something like that.. loss of power .. on 2-3k .. but only on Full Throttle... Tomorrow ..fingers crossed... i get the OEM plugs from Renault.. i work there.. now i have iridium plugs PFR7Z-TG .... i hope this fixes the issue... searching for this fix for a long long time.. fingers crossed that the plugs will sorted all out..

I spoke to Ktec and they advised it could be a mapping issue as well and that they can map it out!

 

[EgasRS]

Did anyone solve this issue? O bought my 197 recently and it started to have the same problem.. trying to solve it..

Any help?

 

[SimiRockStar]

so .. i did the mapping... at our very good company https://www.carpro.si .... the guys did know what were they doing... but they didnt found out whare is the problem... also he didnt fell that missfire...coz he was speeding up on dyno from 1500rpm up... so the problem was not there.. or how should i say.. it didnt fell that flat spot/missfire

I replaced the sparks with oem and 4 new beru coil packs.... so problem still there but i have noticed... that exactly on 2500rpm if i press full gas... i get that missfire and no power until 2800-3000rpm ...

o2 sensors are without any error... but still need to check the parameters of o2 sensors to be sure.. that they are 100% ok..

so...still didnt found the FIX... search continues... ‍

 

[funMACHINE]

have the same on mine , too much throttle between 2000 and 2500 and the misfire starts , exactly at 2500 it
starts to work normal. was on dyno , there was nothing to see , then on testdrive , directly the same ...
installed a lambda gauge , that tells between 2 and 2,5k its lambda 1,15-1,20 and between 2,5 and 3k its 0,65 to 0,7
programming on dyno was 0,92-0,95 all over ...

 

[Kanazir]

So you have lean mix in a spot where car is not pulling well and rich after that which wohld explain simptoms but what would be a reason maybe MAP sensor is not working properly

 

[Kanazir]

so .. i did the mapping... at our very good company https://www.carpro.si .... the guys did know what were they doing... but they didnt found out whare is the problem... also he didnt fell that missfire...coz he was speeding up on dyno from 1500rpm up... so the problem was not there.. or how should i say.. it didnt fell that flat spot/missfire

I replaced the sparks with oem and 4 new beru coil packs.... so problem still there but i have noticed... that exactly on 2500rpm if i press full gas... i get that missfire and no power until 2800-3000rpm ...

o2 sensors are without any error... but still need to check the parameters of o2 sensors to be sure.. that they are 100% ok..

so...still didnt found the FIX... search continues... ‍

What power and torque did you get on dyno?

 

[Frank Perry]

It's often referred to as a "flat spot". There are plenty of posts relating to exactly the same symptoms and they usually occur when you have changed the exhaust to something other than stock. The only way to get rid of it is to stick the stock exhaust system back on. Remapping usually eliminates ~80% of it but there will always be a flat-spot between 2-3000RPM.

My advice is to do your performance modifications and then get it mapped (NOT an off the shelf map!!!). I use the RSTuner from fastchip.nl but essentially the same thing from others where a custom map, also referred to as a calibration file, is created to suit your vehicles parameters/modifications. Since having mine mapped, the power in the lower revs is much smoother and the delivery of the power is consistent throughout the rev range.

Remember, our cars aren't built to have your foot pinned to the floor in 3rd gear at 2000RPM. The power in these N/A engines are at the higher rev-range.

 

[EgasRS]

My car is completely stock, today i change the spark plugs, still the same issue.

Will change the Lambda sensors and start from there... Map sensor, cam sensor and so on...

Today i tried to take it to the rev limit standing still and everything is ok there.. on the road, it starts to fail above the 3000 rpm

 

[Kanazir]

It's often referred to as a "flat spot". There are plenty of posts relating to exactly the same symptoms and they usually occur when you have changed the exhaust to something other than stock. The only way to get rid of it is to stick the stock exhaust system back on. Remapping usually eliminates ~80% of it but there will always be a flat-spot between 2-3000RPM.

My advice is to do your performance modifications and then get it mapped (NOT an off the shelf map!!!). I use the RSTuner from fastchip.nl but essentially the same thing from others where a custom map, also referred to as a calibration file, is created to suit your vehicles parameters/modifications. Since having mine mapped, the power in the lower revs is much smoother and the delivery of the power is consistent throughout the rev range.

Remember, our cars aren't built to have your foot pinned to the floor in 3rd gear at 2000RPM. The power in these N/A engines are at the higher rev-range.

Totaly with you, you can't floor N/A engine that is revving to 8k rpm while turning at 2k rpm and expect it to run smooth. I have modified exhaust and foam filter and never noticed a flat spot but my right foot is waiting waiting for higher revs befor hitting the floor. Even with custom map you can't get N/a engine to have torque troughout the whole rev range.

 

[Kanazir]

I guess people who ride bikes understand this

 

[funMACHINE]

its not the question , nobody expect big power around 2k revs , but with stock exhaust it runs smooth from 1500 to 2500
and now its undriveable in this range . would understand , if the exhaust setup makes 15 horses more in the higher revs ...