Wastegate tuning help

Hey guys, im having a heck of a time here. Im trying to get good solid boost but I cant get anywhere even close...

Im following this guide Ive attached.

Info on car, im running code59 in a turbo sunbird 2.0 with a super60 turbonectics turbo which has a built in wastegate. (which appears to be set around 6 psi)
I checked all hose connections and done see any potential boost leaks at all. did a boost leak test a while back, only small leak i saw was through the TPS sensor which was very minute.


If I turn all the positive and negative adjustment off completely, and just try to tune with the wastgate duty cycle, i have to turn it up to about 96% just to even hit my target boost..then one percent more and it overboosts. Does that even sound right at all??

I double checked my vac lines and actually ran a good sized clean vac from wastegate actuator to manifold vac just to be absolutly sure.

It has no issue building boost, it can go past 20 with ease but I hit my boost point and a couple % of duty cycle knocks my boost clear down to like 9 psi, i just dont understand it. Ive tried messing with every table, is there a mechanical issue here??? any help please.

Are you running an intercooler? If so, double check any hose connections, I've seen many a leak at these connections cause all sort of boost loss. Are you by chance hearing any sound of boost leakage? As for the code59, I have no experience there so hopefully someone who is versed at it will chime in to help you there. Good luck.

Buddrow

I tuned my boost control a different way.

I didn't adjust any of the positive or negative boost control, I'm sure. I set the desired boost and then played with the DC until it got close. The above method is a lot more scientific approach that I might try with my new engine to get the boost dialed. Unfortunately I can't even really perform any boost tuning right now with my slipping clutch. :(

I found in my car that the DC adjustments more fine tuned the onset of boost where as the desired boost was what got it there, almost like a coarse and fine adjustment to closed loop boost control, if that makes sense.

IIRC, changing the Default 1st Boost WG Duty Cycle (KWGDCLOW) really helped get to desired boost without spiking, but it's been a long time since I played with it. Also the Closed Loop Boost Mode settings played an important part in getting the ECM to control boost. These should be set low enough where they are not a concern for you anyway.

Ill have to go back home and check some things... I have car forced into open loop...thats not a cause is it??


And i know its not dc settings....ive made probably at least 30 pulls lol ive done a little of everything. Its either too little or too much... When its anywhere close it will overshoot or undershoot drastically.

Closed Loop boost control, not closed loop fuel control, these are two different things.

I found that the initial DC setting made quite a difference to get the boost control right.

does anyone know much about manual boost controllers? i got some free time and built myself a manual boost controller, i can go through the gears same psi now finally but even the MBC hits boost, then backs off 2-4 psi, I dont know if thats normal or not.

I took my air filter off and pressurized my whole system and found a leak on the pcv hose, wasnt crazy but it was definatly there so I sealed that up, and also the throttle body is leaking some air past the throttle shaft (not fixable)

havent tried the oem boost again yet but i dont know if that small leak would effect it or not.