Hi, thanks for the info Roy, the one car I'm having the major problem with has no fault codes!
I understand what your saying about clip & ignoring some codes.
For a short time the symptoms died away after topping up with fuel. So yes I will change it.
If you have a couple of mins please have a look at the videos here >
http://vtedit.com/espace/this shows some interesting figures jumping around, I'm thinking it is a sensor voltage issue to several sensors. Interested to see what you think.
Cheers
Brian
I don't think I would worry too much about those v.high negative figures Brian. The Renault software system is not that fast and from what I remember these figures can simply be that it has not caught up. Of course knowing their wiring and connections, it would be a good idea to make sure you have no obviously loose or poor connections to sensors. Often just disconnecting and re-connecting them a couple of times if they are quite tight will clean the contacts.
I would pay more attention to things like the injector pulse timings, fuel and boost pressure readings as the engine is revved and if possible on the road being driven. A pulsing can be the boost pressure suddenly dropping and building back up, since it is leaking at the high point of the boost - sometime the intercooler or pipes or joins give but only when the pressure reaches a certain level. We once had an intercooler that opened up near top boost but held fairly well at lower boost!
No fault readouts when there is definitely a fault only means the particular problem cannot be recorded. For instance on an early car like say mine, there is no RCO so if the computer commands something there is no system to tell it whether it has been carried out at all, or carried out correctly. Later car like yours does have RCO on some things so it can check if it has responded and if not it can attempt to correct the fault by sending again but only when it keeps getting an incorrect or no response will it list an error and fault code. For some things, the faulty RCO is enough to cause the ECU to shut down the engine since it can't control it when it doesn't know what is going on. Other lesser faults, it will either go into 'limp home' mode, or maybe allow it to continue and simply display an error to be fixed asap.
So for example no TDC it has to shut down as it doesn't know what the revs are or the timing point, but no cam sensor is not a big deal since it can still work with the TDC senor. With the cam sensor it can respond quicker as the cam is rotating at double speed. Without it, it has to wait longer to react.
Your description of the fault appearing with the storm and wet roads, and improving as the weather eased, suggests maybe water affecting the electrics, so make sure all underneath especially are good; particularly the TDC sensor which is down the bottom. You know that to set the TDC gap correctly you lift the clip and push the sensor actually against the flywheel then release the clip to hold it. Once the engine starts it will push it off just enough.
The second fault caused by lots of water with any car with a 'hot-wire' airflow meter, is the effect on the hot-wire. So make sure the air intake filter is good.
These common rail diesels need to be revved hard occasionally to keep their system clean. The trouble is most owners don't ever rev them above say 2,500rpm thinking it will be good, but actually the reverse is true. Low revs all the time never clears the carbon build up. So your long and sometimes hard drive in Germany has cleaned the system of carbon which is why it no longer gives black smoke on start up or acceleration. The trick is to hold it in first gear or second and take the revs to the governor occasionally (at least once a month) to keep them clean. People wouldn't have EGR problems if they revved them more!
People used to complain diesels were slow as well as noisy and smelly, so didn't want them in preference to a petrol. So they designed these common rail diesels to give the performance but you have to rev them more often.
Roy