Hello all,
Yesterday I brought my car, a 321k (200k miles) well-maintained 2007 Clio RS 197 to the Dutch equivalent of the MOT ('APK') and it was NOK on too high CO emissions: 1.53% (permitted: 0.3%, so 5x out of spec). Since the car is stock I was a bit surprised. Per chemistry class and google it suggests a bunch of things but in short: too much fuel or too little air. Now I'd like to avoid just firing up the parts-cannon and actually be able to diagnose the problem.
I did a few things so far:
1) read out diagnostics code. Note that the car has no CEL, but a code-scan did throw a P0004 - 'Fuel Volume Regulator Control circuit High'. Without knowing the fuel-system of my RS I am not a 100% sure what the set-criteria for this code are? Any help/service data on this would be helpful and appreciated since I can correlate this error to the emissions NOK.
2) insert a fuel system cleaner, drive 50k (35 miles), reset codes. I was able to clear the code but as soon as I switch on the car it instantly pops the code back up.
3) inspect exhaust system: I opened up and the cat looks like new and I don't see any exhaust leaks. I did read elsewhere that people were referring to an 'manifold-cat'. While the header/manifold looks stock (if it is aftermarket I am very impressed with the weld-quality) and looks equally weathered as the stock exhaust it does not contain a catalytic converter. Is this market-specific? Also I would have expected this to pop up as an issue in earlier APKs (It's my third annual check for the car and the first time the emission is an issue).
So my primary suspect is currently in the fuel supply system for which I've read I'll be dropping the fuel-tank. Not a problem but I'd like to understand what sets the P0004 code since it suggests that it somehow measures or derives that the the required volume is high? Could it be anything else than a faulty FPR (which in itself doesn't send a signal I think). It could of course also be that the 2 problems are completely uncorrelated and I'd like to avoid spending a bunch of effort into dropping the tank to only to learn at the APK that I'm back at square 1.
I've read in another thread a question: does my car have an external fuel filter since it's EU? It doesn't, at least per this image:
--> I only have the canister (I at least assume that's what it is), not the filter.
Final question of which I'm affraid I already know the answer: since my exhaust is not split (only at the cat) does that mean that the rear-axle has to come out in order to drop the exhaust in order to drop the tank?
Picture of the car at hand
Yesterday I brought my car, a 321k (200k miles) well-maintained 2007 Clio RS 197 to the Dutch equivalent of the MOT ('APK') and it was NOK on too high CO emissions: 1.53% (permitted: 0.3%, so 5x out of spec). Since the car is stock I was a bit surprised. Per chemistry class and google it suggests a bunch of things but in short: too much fuel or too little air. Now I'd like to avoid just firing up the parts-cannon and actually be able to diagnose the problem.
I did a few things so far:
1) read out diagnostics code. Note that the car has no CEL, but a code-scan did throw a P0004 - 'Fuel Volume Regulator Control circuit High'. Without knowing the fuel-system of my RS I am not a 100% sure what the set-criteria for this code are? Any help/service data on this would be helpful and appreciated since I can correlate this error to the emissions NOK.
2) insert a fuel system cleaner, drive 50k (35 miles), reset codes. I was able to clear the code but as soon as I switch on the car it instantly pops the code back up.
3) inspect exhaust system: I opened up and the cat looks like new and I don't see any exhaust leaks. I did read elsewhere that people were referring to an 'manifold-cat'. While the header/manifold looks stock (if it is aftermarket I am very impressed with the weld-quality) and looks equally weathered as the stock exhaust it does not contain a catalytic converter. Is this market-specific? Also I would have expected this to pop up as an issue in earlier APKs (It's my third annual check for the car and the first time the emission is an issue).
So my primary suspect is currently in the fuel supply system for which I've read I'll be dropping the fuel-tank. Not a problem but I'd like to understand what sets the P0004 code since it suggests that it somehow measures or derives that the the required volume is high? Could it be anything else than a faulty FPR (which in itself doesn't send a signal I think). It could of course also be that the 2 problems are completely uncorrelated and I'd like to avoid spending a bunch of effort into dropping the tank to only to learn at the APK that I'm back at square 1.
I've read in another thread a question: does my car have an external fuel filter since it's EU? It doesn't, at least per this image:
--> I only have the canister (I at least assume that's what it is), not the filter.
Final question of which I'm affraid I already know the answer: since my exhaust is not split (only at the cat) does that mean that the rear-axle has to come out in order to drop the exhaust in order to drop the tank?
Picture of the car at hand
