No Power in 4th gear

[harls]

G'day all,
I have just finished make the engine saving mods to my truck.:049:
Have taken it for a couple of test drives and adjusted the VNT screw accordingly (she now boosts to 18 / 22 psi with no spikes). The only thing is that when changing from 3rd to 4th the turbo lags and has no boost, psi drops to around 2 psi then climbs up to 4 psi and that is it. if i take my foot off the accelarator then reapply it slowly she picks up to 5psi and then takes off, however this is no good when going up hill as she struggles to boost to 5 psi after the gear change.. any ideas??? do i need to switch a vacuum line on the boost control unit or crimp a vacuum hose???

harls

[YNOT]

18 to 22 Psi is too high, you're probably going into limp home mode. Reduce the boost to 16 Psi and see how that goes.

Tony

[patch697]

I agree with Tony 22psi is to hi.

Did you download the reference guide? it has some well detailed adjustment methods in it & from memory suggests a boost range of 12 to 16psi & the likely outcomes for these settings.

[harls]

I did download the reference document. and followed the adjustment methods as detailed. maybe i mucked it up.
I'll have another go over the course of this week after work.
Thanks guys.

[harls]

18 to 22 Psi is too high, you're probably going into limp home mode. Reduce the boost to 16 Psi and see how that goes.

Tony

Tony I have reduced the boost and it now does not pass 15psi. but it still shows the symptoms of going into limp mode in 4th gear???
Any other ideas for what might be causing it?