Jump to content
LegacyGT.com

Not hitting target boost


battelready

Recommended Posts

So im in the middle of a e-tune and ive hit problems with boost. All of a sudden last week the a/f took a a shit and started running rich. Began hunting for leaks and found the inlet was ripped. Replaced it and the a/f's are the same but slightly improved. Played around with the hoses made sure everything is tight and by some miracle the a/f almost zeros out. But the issue remains that the car will not boost past 10 psi. Took of the vacuum line on the waste gate and it only boosts to like 15 psi. At this point i don't know what to think. Gonna run over to my buddies shop and smoke test it but im leaning towards a pre-turbo exhaust leak. Turbos a Kinguawa 16g with 8cm hot side and its only been in for less then a month .

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

If the inlet was ripped, it should be running lean. Do you have an aftermarket intercooler? Maybe your stock one blew apart? Have you checked anywhere else for leaks? What is your IAM or DAM? Chance are if it is running rich and running wastegate boost, you are not at 1 and might be running the limp map. Also, running no line to the wastegate is a bad idea.

 

Tell us a bit about your car(mods) and maybe post a log. From your post, all we can do is speculate. Has your tuner said anything?

Link to comment
Share on other sites

A pre-turbo exhaust leak would cause lean conditions since it pulls vacuum at idle and light throttle. Bnguyen mentioned the main sentiments I would advise: While disconnecting WG for diagnostics, don't continue down that road.

 

Who's tuning your car? I've had a tuner send me on a goose-chase for a problem that didn't mechanically exist and it turned out that the tune they sent was incorrect. This tuner did not try to reconcile even though I was $250 deep in "fixes". Needless to say, I've moved on.

Updated parts list since original part-out here.

 

Original Full part-out of my LGT HERE!

Link to comment
Share on other sites

If the inlet was ripped, it should be running lean. Do you have an aftermarket intercooler? Maybe your stock one blew apart? Have you checked anywhere else for leaks? What is your IAM or DAM? Chance are if it is running rich and running wastegate boost, you are not at 1 and might be running the limp map. Also, running no line to the wastegate is a bad idea.

 

Tell us a bit about your car(mods) and maybe post a log. From your post, all we can do is speculate. Has your tuner said anything?

 

Im getting tuned by cryotuning so I highly doubt its anything to do with his tune. Inlet was the first thing i saw so i replaced it .Mods are grimmspeed intercooler, 16g turbo , cobb downpipe , grimmspeed up pipe , avo filter , valve body mod . Checked all vacuum and boost lines to see if their unhooked and zip tied them down . The turbo to intercooler to the throttle body connections are brand new and tightened down. Ill throw up some logs and data up latter when i get to my car. I think it was running in limp mode but then when i straightened out some of the hoses and reflashed the map, the af's started to come within +/- 2 but still no boost past 10 psi.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

A pre-turbo exhaust leak would cause lean conditions since it pulls vacuum at idle and light throttle. Bnguyen mentioned the main sentiments I would advise: While disconnecting WG for diagnostics, don't continue down that road.

 

Who's tuning your car? I've had a tuner send me on a goose-chase for a problem that didn't mechanically exist and it turned out that the tune they sent was incorrect. This tuner did not try to reconcile even though I was $250 deep in "fixes". Needless to say, I've moved on.

 

Its Dave from cryotuning . Ive seen the map in ATR and it supposed to boost to 15 psi. I only disconnected to the WG to make sure that the turbo itself wasnt shot. Checked the boost controller with a power probe and its working fine as well.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

Dave has great attention to detail. Has he given you any feedback?

 

Sounds like you're doing all the right things. I'll keep digging and try to come up with something worthwhile.

 

 

Sent from my iPhone using Tapatalk

Updated parts list since original part-out here.

 

Original Full part-out of my LGT HERE!

Link to comment
Share on other sites

Dave has great attention to detail. Has he given you any feedback?

 

Sounds like you're doing all the right things. I'll keep digging and try to come up with something worthwhile.

 

 

Sent from my iPhone using Tapatalk

 

Thanks man , yea we're going back and forward trying to narrow things down. Hopefully not a bad turbo. Was a pita trying to get the aftermarket inlet on lol.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

Everything checks out. Looks like all the signs point to the turbo. Leaning towards a leaking or misaligned waste gate. Even with the vacuum line off it'll only boost to 15psi , it should spike higher . Is there any sure fire way to check this? warranting a turbo to Taiwan and back is a long wait.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

Hmm, Taiwanese turbo, eh? I think I've found the problem... ;)

 

But seriously, I agree, it sounds like it's bleeding boost manually. Still we have some options to explore.

 

You could inspect the WG alignment and turbine manually from the DP side. It should spin freely and have next to no play. Anything else could cause this issue.

 

Hook up some low pressure (10 lbs or so) to see if the WG diaphragm actuates. Even if you blow in it, it might reveal a poor spring or poor adjustment.

 

Did the BCS fail? A bad BCS is easy to test and remedy and would definitely cause lower boost levels. I noticed you're still on your stocker. If you need one, I have one that works.

 

Did you keep your restrictor pill? If not, is that recommended by Kinguawa? I had to remove mine for my AVO but honestly, I don't know if it's always required.

 

Other than that you could also swap back to the vf40 or whatever you had on before to isolate a turbo issue. This option sucks the most but it's also the most revealing if the other options check out barring any gross wastegate observations.

Updated parts list since original part-out here.

 

Original Full part-out of my LGT HERE!

Link to comment
Share on other sites

the fact the system only hits 10-15psi with no wastegate reference shows the signal is not the issue.

 

The turbo should hit well over 15psi on a spike with no turbo/wastegate/bcs reference hooked up.

 

Hope it's not a defective turbo but I'm thinking the wastegate is hanging open.

 

Dave

[sIGPIC][/sIGPIC]

Providing unmatched customer service and a Premium level of Dyno/E-tuning to the Community

 

cryotuneperformance@yahoo.com

facebook.com/cryotuneperformance.

Link to comment
Share on other sites

the fact the system only hits 10-15psi with no wastegate reference shows the signal is not the issue.

 

The turbo should hit well over 15psi on a spike with no turbo/wastegate/bcs reference hooked up.

 

Hope it's not a defective turbo but I'm thinking the wastegate is hanging open.

 

Dave

 

Sent you some logs and stuff.

 

Found my leak. Turns out the grimmspeed cobra hose that hooks up to the intercooler to the throttle body was creating a gap when the hood closes and pushes the intercooler with the hood scoop. Still didnt solve the boost problem. Can i increase the preload on the wastegate to see if the factory didnt set it up correctly and will it harm anything if do , if so how many turns translates into what interms of psi? The kinguawa turbos are pretty good. Some OEMS use them and personally speaking both my friend and my brother have a 20g on their sti putting down like 21 psi with no problems.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

Basically figured out the problem or rather a series of problems. So the hidden boost leak was just making things worse the whole time. I figured it'd be a really stupid problem and it was , it turned out being the boost controller. After fixing the leak i forgot to check to see if the boost would spike now that everything was buttoned up. So when i finally took off the waste gate line i gradually boosted it and it hit 18 psi before i let off. So the turbo and waste gate were fine. This basically leaves the boost controller or the lines coming off thee waste gate. I just went ahead and bought a EBC just in case i wanted to upgrade latter down the road , this allow me to change both the lines and the boost controller at the same time.

I bought an auto be more involved in my uninvolvedness . 200k+ Club

If you can't blind them with brilliance, baffle them with bullshit.

My high mileage turd.

Link to comment
Share on other sites

  • 5 months later...

Let me revive this thread...

 

I've been keeping an eye lately on my boost level whether it's hitting target values or not. So far, I've noticed that it can be as far as 2.5 psi off (less than target) when pushing the car close to WOT. My long term fuel trims are spot on (between +/- 5%), although fuel trim D never gets corrected (always been 0 so far). And I know for sure that I've been driving the car in that load/rpm range.

Also, LV is free of FLKC.

Car (05 obxt) is stage 2 and etuned (hiflow invidia DP, sti uppipe).

 

Any additional thoughts on how to troubleshoot this issue?

Link to comment
Share on other sites

Let me revive this thread...

 

I've been keeping an eye lately on my boost level whether it's hitting target values or not. So far, I've noticed that it can be as far as 2.5 psi off (less than target) when pushing the car close to WOT. My long term fuel trims are spot on (between +/- 5%), although fuel trim D never gets corrected (always been 0 so far). And I know for sure that I've been driving the car in that load/rpm range.

Also, LV is free of FLKC.

Car (05 obxt) is stage 2 and etuned (hiflow invidia DP, sti uppipe).

 

Any additional thoughts on how to troubleshoot this issue?

 

What do your wastegate duties look like in those conditions? Could very well just be that the turbo can't flow as much as your target is asking for.

 

Also, FYI, unless you're cruising at high RPMs with low throttle input (say 3rd or 4th), your AF D range won't learn much/at all. It will only learn in closed-loop, and most of the time, if you're in that airflow range in 5th (or 6th, for us spec.B guys), you're going to be in open-loop anyway, which will disable learning (but NOT correction) entirely.

Link to comment
Share on other sites

What do your wastegate duties look like in those conditions? Could very well just be that the turbo can't flow as much as your target is asking for.

 

I am not sure what the wastegate duties are. I need to start logging these.

 

I am pretty sure the turbo should be able to achieve the target numbers because my 06 can (both stock turbos). My 06 has even slightly higher targets than the 05 (in the range of 18-19 psi), and it is able to reach these numbers.

I've seen the 05 showing a 17.8 psi target and actual max reached was like 15.4... It happened several times too.

Link to comment
Share on other sites

Log please, with Requested Torque, rpm, boost error, Primary WGDC, Turbo Dynamics Proportional and Integral parameters. It will speed things up to see a screen shot of your initial and max WGDC tables too. As Rhino above mentions, you may just not have enough WGDC compensation for higher temps, but the log data would tell us if duty cycle is already at max.

 

 

Sent from a device using some software.

Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
Link to comment
Share on other sites

When was your etune done? Was it updated after a seasonal change? I agree that your duty cycle tables are most likely the culprit.

 

The last rev was uploaded to my ECU around Feb 5 of this year. I have not reset it since. But I've never paid attention to boost target at that time.

 

Log please, with Requested Torque, rpm, boost error, Primary WGDC, Turbo Dynamics Proportional and Integral parameters. It will speed things up to see a screen shot of your initial and max WGDC tables too. As Rhino above mentions, you may just not have enough WGDC compensation for higher temps, but the log data would tell us if duty cycle is already at max.

 

 

Sent from a device using some software.

 

thanks for the feedback. I'll see what I can come up with.

Link to comment
Share on other sites

Let me revive this thread...

 

I've been keeping an eye lately on my boost level whether it's hitting target values or not. So far, I've noticed that it can be as far as 2.5 psi off (less than target) when pushing the car close to WOT. My long term fuel trims are spot on (between +/- 5%), although fuel trim D never gets corrected (always been 0 so far). And I know for sure that I've been driving the car in that load/rpm range.

Also, LV is free of FLKC.

Car (05 obxt) is stage 2 and etuned (hiflow invidia DP, sti uppipe).

 

Any additional thoughts on how to troubleshoot this issue?

 

Have you done a boost leak test?

 

Send us some logs we'll take a look!

 

-Brian

Contact us for all your tuning and performance parts needs! Etuning the legacy community since 2008!

Follow us on FACEBOOK | INSTAGRAM

[sIGPIC][/sIGPIC]

Link to comment
Share on other sites

I did not do a boost leak test as my long term fuel trims are within reasonable values (between -2 and +2% for all trims--except trim D which is stuck at 0%).

 

I started logging waste gate duty cycles and I believe 'waste gate pressure'. When I pushed the car, the former went as high as 70% and the latter never passed 9.

 

Interestingly enough, the 06, when pushed, reaches a wgdtc of only 20%. The 06 has a Grimspeed EBCS though. The 05 does not.

Link to comment
Share on other sites

  • 7 months later...

Thread revival #2

 

I did not do a boost leak test as my long term fuel trims are within reasonable values (between -2 and +2% for all trims--except trim D which is stuck at 0%).

 

I started logging waste gate duty cycles and I believe 'waste gate pressure'. When I pushed the car, the former went as high as 70% and the latter never passed 9.

 

Interestingly enough, the 06, when pushed, reaches a wgdtc of only 20%. The 06 has a Grimspeed EBCS though. The 05 does not.

 

Did you get the issue resolved?

Link to comment
Share on other sites

eeeeee nope. I am still like ~2 psi off most of the time. I found an exhaust leak a month ago at the uppipe to header junction. I was surprised to find this as I installed one of these thick Grimspeed gaskets. So now I have that thick gasket plus a regular gasket on top of it. I think it still leaks a bit. Will have to check.

Even after this fix though, still not hitting target boost at all.

 

Can't remember, do you have a completely stock wastegate and wastegate actuator on your turbo? If yes, what kind of duty cycle do you see?

 

On another note, my 06 has a stock vf40 with an AVO wastegate actuator and a grimspeed EBCS. That thing hits target boost almost perfectly every single time. Amazing.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use