I installed the 4k, super 40 and Goerend tranny at about the same time. Pier to the install the truck felt lite and responsive, now it feels heavy and takes more pedal until it shifts into overdrive then it runs good and after 10psi of boost it runs even better. mpg has dropped from 19/20 to 15/16.Anyone have any ideas as to whats going on.

 

sounds like you may need to do some pump tuning. adjusting the star wheel and especially the afc

 

I have done some,followed a thread on tuninng. Removed afc set star wheel to full rack travel at 32psi and backed smoke screw all the way out then took it in till it just touched the diaphragm. Reinstalled afc and ran trk and kept turning smoke screw in 1/8 turn at a time, right now its about 1and 1/2 turns past diaphragm. It might need more I dont know. I was wondering if the gsks were tight enough, I had a mechanic install them so I dont know how many clicks he used.

 

Is the turbo new? If its old and doesn't spool up well, it'll feel like a dog. If there is a boost leak, it will also do this.

Have you done a free rev to see where it will run to? If the springs are too loose, you won't get the full 4k.

 

Very common mistake when removing the AFC cover is to tighten it down where it lands instead of sliding it all the way forward.
Results in poor acceleration.

 

The turbo is new, afc FF, and not sure about free rev, but i have been to 3500. What will i see if gsk is not tight enough and if too tight?? I have checked the normal areas for leaks but looked ok.

 

Too loose, you won't get full revs, need more pedal to drive normally. Too tight, the idle will be high, it will die much easier if it goes under normal idle speed (especially cold), RPM's might hang, less throttle control.

 

When the mechanic installed the gsk he had to adjust the idle, it was to low. Got the idle set at about 800. As far as starting when its cold I have to give it a little throttle, warm it just fires right up. Its been like that since Ive had the truck (about 6 yrs.). Thanks for your ideas.