LNF Boost Problems

[GHuggins]

Having a problem with boost control on one. What's happening is that it makes the commanded or at least very close to the commanded on the first dyno pull, then consecutively drops boost off with following pulls. Will eventually only make 5 to 10psi. Have tried everything with limp settings to the point of all but shutting them off completely. OS has no effect that I can tell. Don't see anything in the log limiting it - no throttle closures and so on...

Car has a haugn turbocharger on it - don't know exact sizing. Has BOV, intercooler, CAI with MAF in behind filter as stock, catless exhaust system.

Any help or insight on how to properly do this is greatly appreciated.

[cobaltssoverbooster]

Hahn should be an s20g...anyways did you disable over boost controls in diagnostics?

[GHuggins]

Yes. I think I might have finally figured it out. I put the higher rpm and mid range rpm and load cam specs back to stock, fixed the leaking waste gate control solenoid hose, put my timing tables back in and it actually built to boost specs every pull after. Only problem now is that after you do 3 or 4 pulls it'll build to 30psi and start sputtering and misfiring, so just need to experiment with the waste gate and Dal tables a little and hopefully I can get it fixed.

Thank you for replying.

[cobaltssoverbooster]

Yes. I think I might have finally figured it out. I put the higher rpm and mid range rpm and load cam specs back to stock, fixed the leaking waste gate control solenoid hose, put my timing tables back in and it actually built to boost specs every pull after. Only problem now is that after you do 3 or 4 pulls it'll build to 30psi and start sputtering and misfiring, so just need to experiment with the waste gate and Dal tables a little and hopefully I can get it fixed.

Thank you for replying.

creep can be blocked using proportional max boost? and pid tables

[GHuggins]

What would be the best route to go about that. In other words a possible "for dummies " explanation... I'm posting the current tune as well if it'll help any. Right now it's putting down 375 to the tire and when the boost jumps to nearly 30 it'll shoot over 400 - really trying to not blow the motor up - lifting as soon as it does this, so would prefer keeping it around 360 to 375 at 23 to 25psi...

I've read some of the how to's, but they don't seem to go into great detail on which way to move things to adjust for something like this.

Thank You Again.

[GHuggins]

Are there any suggestions or guidance you can recommend.

[ECaulk]

I haven't messed with the prop max tables to much, but you're running pretty high wgdc all the way through 7,000 rpm. Might try lowering it a few points over 5,000rpm. I don't recall if the s20g starts running out of steam up top like the little KO4 does

[GHuggins]

I played with the tables and played with the tables. Haven't had one be this big of a pain in a long time... If I put .1 in the wrong spot it wouldn't build boost at all above 10psi hardly. Tapered down less and it was back to spiking too much boost then dropping 5psi and never building back to commanded. I did wind up dropping the wgdc back around 3% as a whole in the higher rpm areas and then went back to using the max allowed boost and max pressure per rpm set point to control it.. Then used OS and air load as best as possible to get it to boost just like stock was capable of at lower throttle inputs.

It is apparently setting a P0101 now and may wind up having to relocate the MAF back before the tb if I don't find any boost leaks then retune for that... Apparently car has had a lot of problems and been through a few owners and tuners over the last couple of years, so not 100% on it yet... Does great for 30mins then sets the code and will go back to running fine for a while until it has the problem again. Either boost leak, wastegate sticking, where I put the MAF back in front of the turbo or something else going on tune wise?