High average knock signal / engine not running smoothly


I have a problem with my Clio 197, year 2006: when on idle, the RPM are moving up and down slightly (not much; something about 50 RPM max, averaging about 830 RPM total). The engine is not running smoothly on idle, when I put my hand near the exhaust I can feel some random bursts (it is not strong and from time to time you can feel a stronger blow of air from the exhaust). I have plugged in my pyclip and found a few things interesting:
  1. PR427 AVERAGE KNOCK SIGNAL - it is getting high values during driving (up to 11k), no error related to knocking is stored but I am worried about that high value of knock signal. At what level should it be maintained - maybe these values are normal? (PR095 ANTI-KNOCK CORRECTION is on 0 CRK - so I think no timing adjustment is applied due to that issue)
  2. PR138 RICHNESS CORRECTION - it gets its value up to 50%, so I think more fuel should be injected. Is this score too high?
  3. PR448 IGNITION ADVANCE - goes up to 58 CRK, how should I interpretate that?

Some facts about the car:
  • I have changed my exhaust to Scorpion resonated.
  • I went to dyno and it got 188HP, so I think it is quite good (changing exhaust without a map has probably taken some HP) - it dies mainly in the upper rev range (Above 5800) the line is straight. I compared it to a different Clio (201), checked on the same dyno, and it is still increasing past that point, getting more HP in the end. Is 188 a good score? What do you think?
  • The sparks have been changed, no misfire stored in ecu.
  • The registered intake temperature was very high in the summer, reaching 50*C/122*F - I found out that the intake resonator box was missing, so I purchased a new one but haven't installed it yet.
  • During my last visit at the repair shop, they found out that the timing belt was loose. It had been changed with vvt and water pump one year ago; an oil leak might have caused it to become loose sooner or it might have been the previous mechanic's fault. I am going to replace it next week.
  • I am running 98 fuel all the time.
Should I be worried about that knock signal and the car not running smoothly on idle? Can it be caused by the missing intake resonator box or by the loose timing belt? Maybe the timing is not right due to that loose belt; how to check that? What should I check or replace to fix that (if it is a problem)?

Thanks for your help!


Paid Member
I wouldn’t worry about it personally.

I haven’t ran the resonator box for years, and I can’t see it making much difference to the running, nor the intake temps.
I also very much doubt the belt is still loose. If the timing wasn’t correct I don’t think it would run anywhere near your quote dyno figure.
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Platinum Member
Let me ask you this: is the car hesitant when you accelerate (other than the standard flat spot)? Does it stutter anywhere in the RPM range?

If no to all of these, then as RSRowe said don't worry about it. The car will definitely tell you when something is wrong, showing up when it drives. Idle behavior should be flat all the time, but even my car occasionally ticks up and down, and its all normal.
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Thanks for calming me down! It looks like I am looking for a problem that does not exist! :grimacing: During acceleration everything looks pretty good, it had a flat spot probably increased by changing the exhaust, but after that it goes smoothly up to RPM cut. Many thanks for your help guys!