2.4 jtd tricky problem
Hi all Alfa fans and drivers!
First of all my English is not so good but I hope it's understandable.
I own my first Alfa for a year now but I still have one problem from the beginning I bought it (156 2.4 jtd).
On heavy acceleration exactly at 2500 rpm the car losses some power, when plugged on computer it shows that pressure from turbine drops at 2500 and at 3000 it rises back again to normal level, so from 2500 to 3000 there is some power missing. The interesting thing is also that when on highway (very noticeable in 5. gear) when I am accelerating with 3/4 throttle between 2500-3000 rpm the whole car is shaking but If i put the throttle to the max, it go smooth with just lack of power between those rpm. So definitely there is something wrong with the car between 2500-3000 rpm and overall it seems, that the car is not going as well as it should go.
Engine is 140hp, I have quality remap 170hp (before remap same symptoms, so nothing changed except a little better performance but still not as good as 170hp should be), I have bought new original turbine, new vacuum actuator, tried 3 different MAF sensor also original one, bought new MAP sensor, egr is blocked and vacuum pipes and turbine hoses are OK. Also checked injectors (4 OK, 1 restored) and Bosch pump (OK) at Bosch service. Overall engine is running healthy (except from 2500-3000) and burn no oil at all. Despite all I still have that problem. Interesting fact is also, that car is chipped and catalyst removed and it doesn't burn black smoke on full acceleration, which isn't normal for diesel especially for chipped one. I have been at 3 mechanics and they ran out of ideas, one told me, that it could be bad ECU but before i change it I am wondering if someone of you guys can help me.