JTDm engine cuts out at 4000rpm
Hope someone can help here, there seems little info on the site about rev limitter for this engine, and my problem appears to be that the limitter is kicking in too early.
Some background: 2005 156 16V JTDm, 108K miles. Had new MAF and Samco boost hoses 3 years ago, regulalry serviced. No fault codes and car drives really well apart from....
Try to get near the red line and the engine cuts the fuel so as to hold the revs. This can be upto 5000rpm in first, 4500 in 2nd, 4000rpm in 3rd or 4th. Also the limit varies, for example if the car in neutral and I rev it slowly first to 5000, limitter kicks in. If I repeat it only gets to about 4500rpm. When the limitter kicks in it has the classic misfiring sound you get with a petrol car on the limitter - splutter / boom noise. There is no black smoke when it does this.
Some threads claim there is no rev limitter on a diesel, so what is going on here ?
I do need to check that the induction hose to turbo isn't collapsing under vacuum, but really doubt this since pulls very strongly at lower revs right upto the problem.
Would appreciate any ideas before I start replacing sensors etc as these not cheap ! My thoughts are turbo boost valve and pipes, then MAP, MAF and cam sensor. But since MAF fairly new, MAP recently cleaned (with EGR and whole inlet manifold) and no fault codes I'm not sure this will help. Did "ECU" (throttle position sensor) reset yesterday and this made no difference.