Hi Folks,
I've posted here in the not so distant past about accleration issues with my 1998 Marea 125 HLX Turbo Diesel. I've now identified the cause of the symptoms (but not the root cause of the problem itself).
I do a lot of motorway driving on the M1 and M25 between Sheffield and Folkestone at the moment. At times, usually after driving through roadworks, I noticed I could no longer accelerate beyond 70mph going uphill, and struggled to get more than 80mph going downhill. I currently have the pleasure of regularly driving through the 50mph average speed check between Junctions 28 and 24 on the M1, and the 40mph - 50mph average speed roadworks zone on the Northern stretch of the M25, when driving East.
Here's what happens. Prior to entering any protracted set of roadworks, I always have full power. My car will comfortably drive both uphill and downhill at significant speeds with full acceleration.
After driving through roadworks for any longer than 10 mins at a constant speed of 50mph at around 1500rpm, by the time I come out the other side of the roadworks, I cannot get beyond the speeds mentioned above when travelling uphill/downhill. Acceleration is very weak - it's like there's nothing there (which in a 5 cylinder Turbo Diesel, is completely wrong). This happens every time, without fail.
However, all I need to do to resolve it is leave the motorway and come to a halt (with the engine still running) at, say a roundabout junction or set of traffic lights. Full power is then restored on lift off, and I can rejoin the motorway a happy bunny!
The key question I have is, what could be causing this? Could it be the Mass Air Flow Sensor playing up? No warning lights are coming on. I've experienced a knackered injection pump before, and this is nothing like it. At the end of the day, full power is smoothly restored after I've come to a halt. If the injection system had major issues, this would not happen!
I'm open to any suggestions....?
Cheers.
James
I've posted here in the not so distant past about accleration issues with my 1998 Marea 125 HLX Turbo Diesel. I've now identified the cause of the symptoms (but not the root cause of the problem itself).
I do a lot of motorway driving on the M1 and M25 between Sheffield and Folkestone at the moment. At times, usually after driving through roadworks, I noticed I could no longer accelerate beyond 70mph going uphill, and struggled to get more than 80mph going downhill. I currently have the pleasure of regularly driving through the 50mph average speed check between Junctions 28 and 24 on the M1, and the 40mph - 50mph average speed roadworks zone on the Northern stretch of the M25, when driving East.
Here's what happens. Prior to entering any protracted set of roadworks, I always have full power. My car will comfortably drive both uphill and downhill at significant speeds with full acceleration.
After driving through roadworks for any longer than 10 mins at a constant speed of 50mph at around 1500rpm, by the time I come out the other side of the roadworks, I cannot get beyond the speeds mentioned above when travelling uphill/downhill. Acceleration is very weak - it's like there's nothing there (which in a 5 cylinder Turbo Diesel, is completely wrong). This happens every time, without fail.
However, all I need to do to resolve it is leave the motorway and come to a halt (with the engine still running) at, say a roundabout junction or set of traffic lights. Full power is then restored on lift off, and I can rejoin the motorway a happy bunny!
The key question I have is, what could be causing this? Could it be the Mass Air Flow Sensor playing up? No warning lights are coming on. I've experienced a knackered injection pump before, and this is nothing like it. At the end of the day, full power is smoothly restored after I've come to a halt. If the injection system had major issues, this would not happen!
I'm open to any suggestions....?
Cheers.
James