Technical 1.3 Multijet No turbo pressure at low RPM?

[bAdamn]

Hi!

I have a 2007 Punto 1.3 Multijet. Apparently someone before me diagnosed a bad turbocharger and two faulty injectors. It was already taken apart so I couldn't see it for myself. I replaced the turbo and all 4 injectors, checked everything else as good as I could, also gave it a maintenance service.

The problem now is something I've never experienced before, which is why I'm clueless: turbo pressure arrives very late. It's extremely sluggish for a long time, no pressure at all, struggles to get up to around 3000-3200 rpm, then it kicks in. Otherwise the engine is running smooth, no fault codes. However I tried reading some live data and it just makes no sense whatsoever, for example the air flow sensor's data and the engine rpm shows the exact same value (over 53000 kg/h and rpm...) which could indicate faulty sensors and perhaps these are the default "no value" values, but they're not constant, also if these values were true then it certainly wouldn't have a smooth idle and I'd get fault codes.

Before reading the live data, I was thinking that the problem might be the lack of backpressure as there's currently no exhaust beyond the DPF, but now with the live data in mind... I'm not sure. I'll see as soon as the new exhaust arrives, but in the meantime I'm interested in your opinions. I was also thinking about resetting the ECU to factory, I know for a fact that they've used the car with the bad turbo for a long time so maybe it just needs to relearn the factory settings.

Feel free to shut down my bad ideas, evidently this is not my area of expertise, it's not something I usually do. Any advice or idea is welcome.

 

[bugsymike]

Hi!

I have a 2007 Punto 1.3 Multijet. Apparently someone before me diagnosed a bad turbocharger and two faulty injectors. It was already taken apart so I couldn't see it for myself. I replaced the turbo and all 4 injectors, checked everything else as good as I could, also gave it a maintenance service.

The problem now is something I've never experienced before, which is why I'm clueless: turbo pressure arrives very late. It's extremely sluggish for a long time, no pressure at all, struggles to get up to around 3000-3200 rpm, then it kicks in. Otherwise the engine is running smooth, no fault codes. However I tried reading some live data and it just makes no sense whatsoever, for example the air flow sensor's data and the engine rpm shows the exact same value (over 53000 kg/h and rpm...) which could indicate faulty sensors and perhaps these are the default "no value" values, but they're not constant, also if these values were true then it certainly wouldn't have a smooth idle and I'd get fault codes.

Before reading the live data, I was thinking that the problem might be the lack of backpressure as there's currently no exhaust beyond the DPF, but now with the live data in mind... I'm not sure. I'll see as soon as the new exhaust arrives, but in the meantime I'm interested in your opinions. I was also thinking about resetting the ECU to factory, I know for a fact that they've used the car with the bad turbo for a long time so maybe it just needs to relearn the factory settings.

Feel free to shut down my bad ideas, evidently this is not my area of expertise, it's not something I usually do. Any advice or idea is welcome.

What readings are you getting about the DPF, if that was blocked then it may account for some of it , also it could have caused previous turbo to fail.
Another thing have you checked for any air leaks after the turbo, hoses /intercooler etc.
As a rough guide with turbo hose off just before inlet manifold, if some one revs the engine it should be hard to hold your hand over the hose from the turbo. Don't let any rubbish get sucked into inlet manifold.
I had an EGR pipe at inlet manifold leaking on a 1.6 MJ which gave funny readings, but that also gave black smoke.
I would have tried to give you some readings from a 1.3 MJ I have, but it is a Vauxhall Combo1.3MJ and the MaxiEcu Scan tool I have can't be convinced it is only the badges saying it is a Vauxhall and not a Fiat Doblo 1.3MJ.
Could you try loosening the DPF at exhaust manifold end and seeing if engine revs quicker to prove if DPF blocked.