91 Jetta with K14 turbo - boost still remains low - what can be the problem?

[SR Heer]

I have an AAZ motor in 91 Jetta with K14 turbo. I just put in new rings, rod bearings, and rebuilt head. It runs fair but I have to put pedal to the floor and I read max 10PSI boost - so I adjusted the waste gate #5 allen wrench adjustment on side clockwise all the way in and then secured. It may have made just a bit of difference  - now max reading is about 12PSI boost - so how do I tell if the waste gate is leaking exhaust and or maybe turbo fins worn? What and how can I tell why it is not boosting higher? K14 turbo feels good as far as turbine bearings and does not use oil. Could it be the Injection Pump? I swapped out the stock IDA metering pin with one from a 1.6TD - still no noticeable difference! I also can hear the turbo spooling up and down as I pull under load and then let off - I think it sounds normal but this is the first IDI - turbo diesel that I have had. Any suggestions will be appreciated! Thanks

[RabbitJockey]

i know k24s are notoroious for sticky wastegate valves, have you turned up the main fueling screw?  are you sure all your hoses are tight?  whats the history of your turbo?  on my stock 1.6td i couldn't get more than 15psi with out turning up the main fuel screw, i would think with a k14 and an aaz you would be able to get more than 12psi but it's hard to say.

[SR Heer]

Yes I turned up my main fuel screw until it was a bit on the high side as far as idle goes and tried and that helped some but that is where I get what I get at 12PSI boost - I notice a just bit of black smoke when I floor it but nothing to write home about or help discourage mosquitos with so maybe it it fuel - is there any way I can crank up the screw for main fueling and maybe reposition the throttle to get the idle to come down more into normal range? Is this even feasible? 

[8v-of-fury]

Could you possibly have an exhaust leak between engine and manifold, or manifold and turbo? Or even a cold side leak?? If there is an exhaust leak, it wont spool the turbo.. no boost, no fuel enrichment. If there is a cold side leak, the turbo will be spoolin' its heart away, but the boost never gets to the engine.. and the lack of boost means the pump never ups the fuel..

Just something to think on.

Also! Just so you know.. 12-15psi from a k14 is within its efficiency range, and anything outside that is completely redundant.. Do you have an Intercooler? Over 12-15psi sans inter-cooler is SUPER REDUNDANT, as the air is so hot entering the engine its actually doing less for performance.. and is only gonna hurt your EGT's.

How many miles on the turbo?