Independent Renault Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter #1
Hi there,
Does anyone know if theres a tempreture sensor that conrols the turbo?
The reason being that when the weather is hot or very warm my car drives great, but when its mild, cold or even raining it seems to struggle and I have to accellorate hard to get the car moving.
my car is a scenic 1.9 dci on a 54 plate. Many thanx in anticipation
 

·
Premium Member
Joined
·
43,291 Posts
There is no temp sensor that directly controls the turbo but there is an air inlet temp sensor and the ECU monitors this and can adjust the fuel air/mix proportionally. Has the air filter been changed recently. Generally engines prefer cold dry air.:)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #3
There is no temp sensor that directly controls the turbo but there is an air inlet temp sensor and the ECU monitors this and can adjust the fuel air/mix proportionally. Has the air filter been changed recently. Generally engines prefer cold dry air.:)
Hi madnoel10 yes recently had air, oil and fuel filter changed along with the oil. Theres no fault light on and also renault reprogrammed the ecu with the latest software.
Thanks for the reply
 

·
Technical Supremo, Platinum Member
Joined
·
7,904 Posts
Usually turbo Diesels love cold damp weather
mine just loves cold misty mornings the cold and
damp help cool the air getting to the engine
giving a denser charge and more power so
if yours is down on power in those conditions
something must be wrong.
 

·
Premium Member
Joined
·
43,291 Posts
It could be a duff inlet air temp sensor or MAF unit and as far as I know both are incorporated into the MAF unit on the 1.9 Dci engines:)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #6
Hi Ralph thanks for the reply that was my thoughts too.

Hi madnoel is there anyway I could test the MAF sensor as no faults are showing up, is this possible that there could be a fault even if none are being displayed or reported?

many thanks both of you for the replys
 

·
Premium Member
Joined
·
43,291 Posts
MAF units can be quite delicate things and if they are giving the wrong readings the ECU may just accept them to be a true reflection of what is actually happening - so therefore not record a fault. I am not sure if there is a way of testing them without diagnostic equipment but I have heard of people disconecting them as this forces the ECU to go into default mode. Once disconnected there then is the risk the ECU definitely will record a fault. It may be worth checking if the MAF is dirty as that would affect its readings. An MAF is basically a small electric element which is gently heated and as the air passes across it and as a result will cool. The ECU records any changes in electrical resistance as a result and alters the amount of fuel being injected.
Was the problem there before the ECU software was updated??:)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #8
Hi madnoel thanks for that very detailed explanation. yes the fault was there before the ecu software was updated, I actually took it into the dealers who couldn't find any faults with there diagnostic equipment.
Just find it weird that when the weather is really hot it goes really well the way you would expect yet when cold or rainy it just seems to struggle.
Another thing I noticed and the original reason it went into the dealers is that If you go up a slight incline the speed just drops off, Is that normal?
Once again thanks for your time and knowledge
 

·
Premium Member
Joined
·
43,291 Posts
Never having driven a Scenic 1.9 Dci in all honesty I couldn't say what their uphill performance is likely to be. One other possibility (I'm clutching at staws here) is that the turbo pressure sensor or its solenoid isn't performing correctly. This is to help the turbo maintain an even intake pressure. Should this pressure drop for whatever reason the ECU will tend to reduce the amount of fuel injected. I doubt very much any diagnostic system could take accurate readings whilst the vehicle is stationary especially when the problem only seems to occur when the engine is under load and being driven. It would be interesting to see what the live turbo pressure is whilst driving. There are some diagnostic systems that can record live data. I am not being critical of the garage you have used but in my experience most run-of-the mill garages seem to have limited diesel skills so the opinion of a diesel specialist may be worth considering.

As an after-thought has the EGR valve ever been cleaned or checked because if it is not performing correctly it rarely shows up on a diagnostic check for some weird reason:)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #10
The car went into a renault dealer. Thanks for your input. Think I will have the turbo pressure tested and check the ecu out. Will then look at the egr valve many thanks will post what ever comes back :)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #11
Hi there,
Does anyone know if theres a tempreture sensor that conrols the turbo?
The reason being that when the weather is hot or very warm my car drives great, but when its mild, cold or even raining it seems to struggle and I have to accellorate hard to get the car moving.
my car is a scenic 1.9 dci on a 54 plate. Many thanx in anticipation
this problem turned out to be a duff map sensor that was not being picked up by the dealears diagnostic kit but still charged and told nothink was wrong with the car what a laugh
 

·
Registered
Joined
·
45 Posts
Discussion Starter #13
Glad to hear you got it sorted Bigegg. Was it the turbo pressure sensor or the MAF sensor that was replaced??:)
Hi madnoel10 it was the MAP sensor that was replaced what a difference the *********** told me nothing was wrong after they test drove it too. I belive this sensor advances the ignition timing which was where the lack of power was. I got a Map sensor from a salvage yard for £35 compared to renaults £100
 

·
Premium Member
Joined
·
43,291 Posts
Are you referring to the sensor that monitors manifold presssure on the inlet pipe comimg from the inytercooler or the unit which attaches to the air filter (similar to the unit picture attached)??:)
 

Attachments

·
Registered
Joined
·
45 Posts
Discussion Starter #15
Are you referring to the sensor that monitors manifold presssure on the inlet pipe comimg from the inytercooler or the unit which attaches to the air filter (similar to the unit picture attached)??:)
Refering to the (MAP) manifold absolute pressure sensor that sits on the inlet pipe from the intercooler and not the (MAF) mass air flow meter that attaches to the air filter box. Hope this clears it up
 

·
Premium Member
Joined
·
43,291 Posts
Refering to the (MAP) manifold absolute pressure sensor that sits on the inlet pipe from the intercooler and not the (MAF) mass air flow meter that attaches to the air filter box. Hope this clears it up
Thanks for your clarification - the sensor you refer to is also known as the turbo pressure sensor which the ECU monitors to control the turbo wastegate mechanism.:)
 
1 - 16 of 16 Posts
Top