LNF getting boost limiting on stg tune

[TroyKreft]

I've been having problems with my boost being capped to 22psi for a few months now. As soon as it passes 22psi, the waste gate starts pulling back from 100% to 85%, any ideas on where I should look for the problem?

Problem seem to develop same time summer temps came around. I didn't notice this problem at all in the winter, but I remember noticing that my lb/min would stop at a certain number & not go higher, I'm thinking it was 35lb/min, but not sure.

My TtL(DAL) does command higher than 255, does the "Turbo Thermo Load Limit", which is set to 255, limit my DAL to 255, but I wouldn't think I would be getting the surging if this was the issue?

I had a LDK engine put in my car 12k miles ago. The car has 200k miles. I have stg1,CAI, DP,z54 turbo, IC tubes & small aftermarket IC.

Injector constant: .0258
Uncorrected duty cycle is 100% on all points in the right column.
My "Pressure RPM Factors" are [email protected], [email protected], [email protected], [email protected], [email protected]

Recently I put the stg1 tune back in to see if my other problems go away. Then I changed my injector constant by 10%, because my long term was -10%. This week I started doing half % corrections to the MAF freq.

My other problems if they have any relevance to this issue, is I seem to be getting 10 knock retard at light load low RPMs. You can see the problem in my attached log, but only 5, as I reduced the knock limit to 5 at low RPM, as 10 retard leave me with no power at all & blurps out the exhaust on shift. I rocked the car back & forth & shook the exhaust, I didn't really find anything hitting that would set the knock sensor off.

I was getting bucking at around 1500RPMs, but the tuning of the fuel this week seems to improve that a lot, but not gone.

If there is any suggestions on the other issues I've been seeing would be helpful.7-14-18.Channels.xml7-14-18pulsating.hpl7-14-18.Gauges.xml7-14-18.Graphs.xml7-14-18.hpt

[TCSS07]

post a log and tune

[TroyKreft]

post a log and tune

I just updated the bottom links, hope they work now.

[TCSS07]

if you didnt change your injectors leave the injector constant alone and just make maf changes to bring the trims inline
id put the wastegate settings back to the gm stage setting - ive hadn't had to mess with those to make/keep boost - same with torque to load table, i maybe added 10-15% to the upper areas
are you still getting the same issues with the stage file in? boost,surging or anything?
heres some good info on lnf tuning - https://forum.hptuners.com/showthrea...357-LNF-Guides
set all the base spark tables to the same so it stays more consistent - start with min/min for all 4 - zero out burst knock - may help with the low end knock if not you'll have to remove a degree or two
you'll be able to find out more about the MBT spark tables and vvt cam tables from the link posted above but use them with some caution
i copy the min/min spark table that i use for all 4 base spark tables to the MBT tables and add 10 to all - to start out
put 1 in temperture control for the cat - if catless and for tuning purposes since it will screw with your afr
use these torque management settings to make sure ecm isnt limiting still for any reason
maximum torque % vs rpm - 0,1,7 leave factory - 2-5 100%
egt torque 100%
max torque - max torque % and max torque 100%
max air load torque - leave alone under 4k but put 91% from 4k to 6500
brake torque 100%
i left boost control gm stage settings
About the maf stopping at 35lb - make sure your wot fueling is accurate

[TroyKreft]

I changed the injector constant back & re-tuned the air freq on a fresh stg tune. Only got 18lbs of boost. I raised the DAL to 230 & my pulsating is back, but at 18lbs.
I checked the plug gap, in-case it is blowing out the flame & the ecu is seeing this. It was 32-35. I also added EGT to my log.
7-28-18b.hpl 12-23-17.Channels.xml 12-23-17.Gauges.xml

[cobaltssoverbooster]

egt is useless unless you have an external gauge. the value is a calculation and highly inaccurate
also re-gap plugs to .028-.030 you'l never blow one out again.

[TCSS07]

could you post the current file

[T-Man]

I've been having problems with my boost being capped to 22psi for a few months now. As soon as it passes 22psi, the waste gate starts pulling back from 100% to 85%, any ideas on where I should look for the problem?

Problem seem to develop same time summer temps came around. I didn't notice this problem at all in the winter, but I remember noticing that my lb/min would stop at a certain number & not go higher, I'm thinking it was 35lb/min, but not sure.

Injector constant: .0258
Uncorrected duty cycle is 100% on all points in the right column.
My "Pressure RPM Factors" are [email protected], [email protected], [email protected], [email protected], [email protected]

Pressure RPM factor is a boost limiter based on BARO readings/sensor. Set your WGDC at 65-70% and set the pressure RPM factor table to 8 across the board. Then go test it.

[metroplex]

Any updates on this?

The Pressure RPM Factor table doesn't seem like a clean Pressure Ratio limiter. The original poster's setting of 2.852 and 2.703 at the high RPM range would still limit it to about 26.76 psi and 24.6 psi respectively, not 22 psi.

[TroyKreft]

I don't remember for sure, but I had a point in time where I couldn't make boost, end up being the OEM wastegate diaphragm had a hole in it. I had to pull my numbers back into reality, because boost went crazy once wastegate was fixed. A side note, I had a new weird sound when letting off the throttle while under boost, before I fixed the wastegate. Sounded like the blowoff valve releasing too early, if this helps. Sorry, my memory is very good. I don't remember this problem is related to this forum post.