Losing power

[petercz]

Ok yesterday I have replaced transmission, now it's shifting really good and smooth, but still low power... any ideas ?

[v8volvo]

Have you checked to make sure there's no restriction in the fuel supply system or air intake tract? Have you checked boost pressure? Does it smoke a lot as well as being low on power, or is it slow but smoke-free?

If your motor has EGR, you may also want to take the pressure relief valve off the front of the intake manifold and look inside and see how much buildup there is inside -- on the EGR motors sometimes there can be enough crud accumulated in the manifold to constrict the intake passages and cause a reduction of power. Usually this only shows up at higher RPM and in a mechanically injected D24T without a MAF sensor will probably be accompanied by quite a bit of black smoke...

A nice shifting ZF transmission is a real pleasure, glad you got that part of it sorted. The lack of power should be pretty simple, let us know what you find and we'll see if we can get it figured out!

[petercz]

So last weekend I have checked fuel system, boost pressure was only 0.6bar (normal is 0.8bar) and I have no EGR...
...but this week my diesel mechanik fully rebuild IP and he said it was totally worn out, no wonder after 400000km...
now it runs really good again

[ngoma]

Great news! That is a good mechanic that can fully rebuild that IP. Did the mechanic say what part(s) were worn out?

[petercz]

Yes, but i don't know how it is called in english, maybe shaft bushing or so...especially

[petercz]

This week I have free time again, so testing may continue
From stock rebuild IP I have turned the fuel screw 1/4 turn (for more I must move the throttle spindle, to reduce idle), now it's again much louder, friend said I'm on the edge but it almost doesn't smoke... wth is wrong with it ?

[745 TurboGreasel]

You have full boost by 3000 RPM?
10-11PSI?
~19 sec 1/4 mile?

If so, it's probably normal.

[petercz]

Yep, about 12psi... So why I can't turn it up withount increase of noise and creak from ip after start ?

[745 TurboGreasel]

Have you forgot to block the safety valve on the intake?
More on creaking noise?

[petercz]

I don't have the safety valve on the tic intake...
Creaking noise is 2-3sec after cold start, it's like a metal on metal friction or belt slipping, these 2-3sec it holds idle like warm, after that rpm increase to cold idle level