Hello all, thanks for your replies.
Ben, I am the poster from the other groups, over a year on and still not resolved. The new ignition module fitted last week is indeed the new rounded type like yours. The ECU software has been updated countless times. John, apparently the knock sensor has been replaced, along with the MAP sensor, coolant temp sensor, TDC sensor and so on. All this replacing started initially after the garage felt just once when it was bad. It was barely driveable, and when they got it onto the diagnostic machine, it reported no faults. Up until they actually felt it, they were about to return it to me untouched, as I feel they trusted their computers to tell them if a fault was present. So they have experienced it themselves, but not for a long time, so as they say they have replaced all parts that could have a bearing on this type of running, they think it's not there anymore. But it certainly is! The clatter coming from the engine really concerns me, but again, unless they hear it, they're not likely to do anything. I don't have a video camera!
Thanks again, any more tips please pass them on.
|
I know you have already tried another dealer, but why not try an experieced independent guy, he may be able to use some common sense and good old fashioned experienced detective work.
I don't know, but could this be an earth fault?
Well, the other option is to do what my dad did with his generally rubbish 206; he took it to a Citroen dealer and bought a Picasso HDI.
|
Hello again Ben,
I've often thought about taking it to an independent, but the car still has half of its three year warranty left, so it could leave me on dodgy ground if it was tinkered with. As for the other option, I don't have enough money to take the hit in depriciation if I sell the car, and I've decided that I shouldn't have to sell the car just because the manufacturer appears unable to mend it, so I'll just have to keep on at them.
Thanks.
|
Just get an opinion from an experienced independent, say £20 for his time could save you far more than that in inconvenience and travelling to the franchised dealer.
The depreciation hit on a 18mth Xsara is likely to be huge. I don't envy you.
|
If all the possible obvious causes have been eliminated by replacing components it sounds like either an intermittent earth fault or a weakness in the wiring loom somewhere. Unfortunately these type of faults can be a nightmare to find, but you don't need me to tell you that! Is the fault weather dependant? Worse or better when very damp or dry? It's also not unknown for replacement components to be duff too, especially if they were from the same batch as the one replaced.
You have my deepest sympathies, for what it's worth.
Good luck.
|
When the problem started, it would only feel rough when the engine was started warm, or the car had been warmed in hot sun all day. Since all the parts have been changed, the problem has taken on a random nature. The roughness is now often there from cold, and does indeed seems to be worse on damp days, but then on occasions it can run perfectly even though its pouring down. Two things that definitely have an effect though (I've told the garage about these but they haven't took any notice so I'm still b*****ed). Firstly, if its running rough, a tip I was given by a Xantia driver with similar problems (whose miraculously cleared up on their own) is to hold down the gas pedal slightly with the ignition off, and let go as soon as the ignition catches. The extra 'blast' of revs often clears the problems up completely for that journey until the car is restarted. The other thing I've found is that on frosty nights when I've had to start the engine to demist the car (basic 1.4L - no a/c!) I'm sitting there for maybe 5 minutes with the engine running before I move anywhere. If the engine is left to idle like this from cold for this long, it always runs fine once I get running.
I was in the car just before while it is having a bad day, and my passenger remarked that it simply sounded like the engine had no oil in it. It really does clatter bad. Of course the oil is fully topped to just below the recommended upper limit, and even the car tells me the oil level is fine.
Anyway, if you can give me any explaination for the above situations, please let me know! Thanks.
|
If it sounds like no oil - could it be the knock sensor isn't working properly. Its quite possible to hear these working, at times, as they change the timing to cater for overun & then pulling away - quite noticible for example when anticipating a roundabout and then pulling away when you get a gap - its the sort of sound that would be masked by a gearchange for example - but is a metallic click noise - "pinking".
Just a thought - what does anyone else think?
|
|
Just a thought, do you have access to a camcorder? Keep this in the car with you, and as soon as the problems start, start filming, then take this and show it to the garage, may sound bizzare, but it worked for me once.
|
The noise you can hear is almost certainly the engine 'knocking' - this is due to the computer changing the timing, which it usually does in response to the knock sensor to avoid the knocking when difference octance fuels are used. Excessive knocking can cause engine damage eventually, as the petrol/air mix is detonating rather than burning. The computer is presumably not recording an error code, as the sensor is not showing in error, it's just not giving the correct information!
I think you are going to have to take it to a specialist - they may even have seen it before and say "Oh, it's the XYZ, we've done a few of these". You could even try a phone call - they may give you some ideas.
Bit annoying on a nearly new car, but main dealers are well known for farming out these sort of niggly problems to specialists anyway!
Richard
|
Try it on a tank of optimax and see if it makes it better or worse.
I do believe the knock sensors have no feedback and the ECU cannot tell when they are broken.
|
Try it on a tank of optimax
Why is optimax "supposed" to be better than other brands? (excluding supermarket petrol) Anyone have any data to back it up?
|
Optimax is higher octane, and is more highly refined - I think it has a lower final boiling point, so is comprised of 'lighter' fractions of the crude. It is only made at Shell's Stanlow refinery, so when you buy Optimax you are getting Shell petrol, rather than all other fuels which are just supplied from the nearest refinery, or supermarket petrol which is bought on the spot market and might come from anywhere!
Richard
|
|
I've been considering trying Optimax for a while to see if there is any difference in the running, so I'll let me fuel run right down and try a tankful. If I let the fuel run down to the low level warning, would the difference be noted after 1 tank of Optimax, or does it take the car longer to recognise the change in fuel grade? The manual does indeed state that the car is designed for 95 octane petrol, but that extra performance will be achieved from 98 octane. Are there any other obvious tests that could be done to determine a faulty knock sensor? The garage appear to be of the opinion that unless the ECU tells them a part is faulty, everything is OK. Thanks.
|
One more thing, if it is the knock sensor not working properly, apart from the clatter I get, would it give me the symptoms I'm getting of poor performance and accleration? On other days when the car is just a bit 'off' it can be rough and a bit lethargic, but the clatter isn't really noticeable. Other times it can be quiet at the start of a journey and then clatter like an old hackney cab by the end. One thing I've always noticed about the clatter is that if it is present and I'm stuck for a minute or so in stationary traffic, as I move off again the clatter is very pronouced and the move off can be really rough, almost as if the car hasn't got the power to pull away smoothly.
Thanks again.
|
According to my haynes jeep manual, you can check the knock sensor yourself. Connect a timing light according to the manufacturers instructions and start the engine. Have an assistant hit the engine block near the sensor (not too hard!) and watch the timing marks. The timing should retard if the system is working ok. If not, either the sensor or the wiring is faulty.
I've not done this, and I don't know how practical it would be on your car, access is pretty easy on the jeep.
Hope it helps.
|
Hello all, me again. I've had the car running for a few weeks now on Optimax, basically to see if the knock sensor is working and will tell the car. It seems that when the car decides to run as it should, the engine is indeed a bit smoother than normal, and picks up better from lower revs. When the car is having an off-day, the ride is exactly the same as when the tank is full of normal 95-octane petrol. Apart from that, every time the car is started from cold when the weather is icy cold and frosty, the car runs fine. Started any other time, and its a lottery.
Is it possible for a knock sensor to work at times and not others, or do they just die? If a knock sensor didn't give a signal out, would the engine retard the ignition to prepare for lowest-grade petrol to be safe, hence my often useless preformance? Sorry I might be grasping at straws here, but because a bad ride is just of the same severity under 95 and 98 octane petrol, after the tips I've been given here, I'm thinking it could be a culprit.
Could anyone confirm where the knock sensor is found on this engine, (2001 Peugeot/Citroen 1.4TU)? The only one I can see it being is the one screwed in right at the front of the engine as you look at it (sorry for the bad description - not too sure how to describe it, its screwed into a semi-circular area in front of the main engine block as you look from the front) and as Ben said before, would the engine know if it was faulty?
Sorry for so many questions, thanks for reading.
Idge.
|
I can't help you on the location of the knock sensor, but when you *do* locate it, and if it is accessible, you could try unplugging the wire from the back of it, to see if your engine then has the problem *all* the time...
That would at least narrow things down a bit.
Dave.
|
Just a thought, maybe it is not an engine management or sensor problem, could it be a problem with the cat? I recently resolved a long standing problem on an escort which had intermittent loss of power and a horrible rattle which the owner put down to loose underbody trim. A piece of the monolith had broken out of the cat and would occasionally sit across the outlet from the cat causing the loss of power and engine noise.
Andrew
Happiness is a T70 at full chat!
|
|
