Title: new exhaust -> more "diesel" sound and lack of power
Post by: Lennart Sorth on May 24, 2008, 02:42:19 pm
The exhaust on our 2002 2.2dci recent broke, half an inch behind the second catalytic converter (positionwise right under the gearlever). It might have been possible to weld and have it last a few months, but we opted to let the Renault garage replace BOTH cats (gulp!), as they come as a kit from Renault.
However, when the car was ready, it now has a distinctly more audiable "diesel" sound when engaging, but whats worse, it seems to be low on power when engaging.
As soon as the engine gets into the turbo-range, there doesn't seem to lack any power.
Idle has also become a tad irregular - sometimes the whole car shudders - not violently, but enough to worry me. We havenøt got a clear image weather it is worse when cold or hot - for the time being it simply seems to happen occationally.
Other times, it idles fine, so its some periodic error.
The "diesel" sound could be explained by the now clean piece of exhaust from the exhaust manifold and back towards the silencers. Both silencers (one piece) are still the same.
The lack of power at ver low revs is however a constant problem - cold and warm. I always used to have the impression one COULD make the wheel spin when setting off, but now that would require revving the engine quite a bit, which would kill the clutch.
Now - spinning the wheels aren't my biggest priority - its just to describe the lack of power :-)
I took the car to the garage, and they were as puzzled as me, - but we ran it through diags and found nothing except a probably old code for a heater-plug which was replaced a year ago. We deleted that code, and drive the car for some 10 miles, and the mechanic agreed that it would seem a bit low on power, and he even agreed to the diesel sound. The poor idle was sadly not very apparent while I was there, but it was enough for him to notice as well.
No errorcodes were stored after the test drive, and the only thing he could think of was injectors, but as this fault was 100% coinciding with them replacing the cats, it sounds unlikely (but of course not impossible). Also, it would be expected for a failing injector to be niticed by the computer.
I have now poured a can of injector cleaner in the tank, and we will see how things are when the it has gone through.
As far as I know, the cats have no oxygen sensors or any other feedback to the computer, so how fitting new cats can affect the running is strange.
The EGR valve could also be under suspicion , but firstly we're using the guru-advise (=Roy) to clean it regularly by running in 2'nd gear on the rev limiter once or twice per tankfull, secondly EGR problems tend to cause lack of power at high revs - where we seem to have all the expected power.
Has anyone experienced similar power problems after replacing exhaust parts ?
/Lennart
However, when the car was ready, it now has a distinctly more audiable "diesel" sound when engaging, but whats worse, it seems to be low on power when engaging.
As soon as the engine gets into the turbo-range, there doesn't seem to lack any power.
Idle has also become a tad irregular - sometimes the whole car shudders - not violently, but enough to worry me. We havenøt got a clear image weather it is worse when cold or hot - for the time being it simply seems to happen occationally.
Other times, it idles fine, so its some periodic error.
The "diesel" sound could be explained by the now clean piece of exhaust from the exhaust manifold and back towards the silencers. Both silencers (one piece) are still the same.
The lack of power at ver low revs is however a constant problem - cold and warm. I always used to have the impression one COULD make the wheel spin when setting off, but now that would require revving the engine quite a bit, which would kill the clutch.
Now - spinning the wheels aren't my biggest priority - its just to describe the lack of power :-)
I took the car to the garage, and they were as puzzled as me, - but we ran it through diags and found nothing except a probably old code for a heater-plug which was replaced a year ago. We deleted that code, and drive the car for some 10 miles, and the mechanic agreed that it would seem a bit low on power, and he even agreed to the diesel sound. The poor idle was sadly not very apparent while I was there, but it was enough for him to notice as well.
No errorcodes were stored after the test drive, and the only thing he could think of was injectors, but as this fault was 100% coinciding with them replacing the cats, it sounds unlikely (but of course not impossible). Also, it would be expected for a failing injector to be niticed by the computer.
I have now poured a can of injector cleaner in the tank, and we will see how things are when the it has gone through.
As far as I know, the cats have no oxygen sensors or any other feedback to the computer, so how fitting new cats can affect the running is strange.
The EGR valve could also be under suspicion , but firstly we're using the guru-advise (=Roy) to clean it regularly by running in 2'nd gear on the rev limiter once or twice per tankfull, secondly EGR problems tend to cause lack of power at high revs - where we seem to have all the expected power.
Has anyone experienced similar power problems after replacing exhaust parts ?
/Lennart
Title: Re: new exhaust -> more "diesel" sound and lack of power
Post by: renaultbiler on May 24, 2008, 06:25:17 pm
How about faulty new cat ??? Clearly the engine is working harder and thereby is not giving the same power output to the final drive... ???
Title: Re: new exhaust -> more "diesel" sound and lack of power
Post by: Anders Dinsen on May 24, 2008, 07:34:23 pm
I think it's a good example of how cars have feelings! Sometimes people get sick when they start thinking about their health. Your car has been given a chance to rest in a garage with other cars with sicknesses - and the whole thing was just too much for it! ;D
Seriously... I agree with Tom that it may be the new cat being at fault, but first - how about inspecting and cleaning the EGR valve? Even though you do preventive maintenance on it, it may still have clogged up and is no longer able to close completely. It could also produce the symptoms you are seeing, and as it's sitting in the exhaust side which has been worked on, it's more likely to have developed a fault now than injectors or anything else.
- Anders
Seriously... I agree with Tom that it may be the new cat being at fault, but first - how about inspecting and cleaning the EGR valve? Even though you do preventive maintenance on it, it may still have clogged up and is no longer able to close completely. It could also produce the symptoms you are seeing, and as it's sitting in the exhaust side which has been worked on, it's more likely to have developed a fault now than injectors or anything else.
- Anders
Title: Re: new exhaust -> more "diesel" sound and lack of power
Post by: Lennart Sorth on May 24, 2008, 08:22:53 pm
Your car has been given a chance to rest in a garage with other cars with sicknesses - and the whole thing was just too much for it! ;D
oh thanks, just the support I was looking for :-)Quote
how about inspecting and cleaning the EGR valve?
yep, I have the same plan - either by me or the garage - as you know I don't share the same country as the car most of the time :-)However, all the EGR problems I have heard about gave powerloss at higher (turbo-) revs, whereas our cars problem is the opposite. Only idle and <1500 revs.
/Lennart
