Lost my morning boost, now I’m limp...

[Carcinogenx]

Technically, a true title.

Hello Everyone! Recently on my drives to work at 4am, when I hit the onramp to the interstate my Sonic builds boost like normal, then it just dumps it all for no reason and I lose the turbo. I can still limp to work, but it sucks! Used to be I could pull over, come to a stop, and if I accelerated slowly and kept the boost down, the turbo would work again. As time progresses, that doesn’t “fix it” anymore. When I came to a stop on the off-ramp the turbo used to kick back on, but not always anymore. So the issue is getting worse. In the hot afternoon on my way home I’ve never had issues at all, or any other time for that matter. It’s only ever happened on my drive to work when it’s cool out.

This began maybe 2 months ago? 2013 RS Auto. I’m not getting any CEL. When it happens the car runs fine, just gutless without the turbo. I’ve modded it with an CAI, Downpipe, ported intake, bypass the bypass mod and a custom BNR tune. Thought it might be the PCV valve so I put on a new valve cover gasket. That didn’t help. My check valve is present. I cleaned it with some Q-tips.

What else should I be looking at? I’m grateful for any suggestions.

 

[JTee2017]

Search this forum using Google. A couple possibilities to your issue. They've been covered in the forum. . often.

 

[Carcinogenx]

Search this forum using Google. A couple possibilities to your issue. They've been covered in the forum. . often.

Okay...So, I guess I should have mentioned that I researched this to the best of my abilities before posting. I used the search, looked through a ton of threads, read page after page of posts, and haven't come across this issue.

I don't know what other people are calling this problem. I don't have a code to search. I'm obviously searching for the wrong thing, so how about a little direction? Something helpful would be nice.

 

[Frostheave]

Following mine started doing the same today

 

[EyeluvSmegma]

Search this forum using Google. A couple possibilities to your issue. They've been covered in the forum. . often.

Welp, for 1, the search option here is poopie. 2, searching this forum using Google is hit and miss at best. In the time it took you to say "Google it you could have instead been helpful. But, from experience this is what most people get from the been here done that crowd. Which is also a contributing factor of this forum being nearly dead. Just my .02

 

[Maddmatts]

There might be a pending P0299 code which won't trigger the CEL but will limit boost to around 5 psi for as long as it's pending.

Check for the code with a scanner and clear it if it's there and see if the symptom persists.

The diagnostics on this code are incredibly stupid. While the pending code is there, it continues to monitor expected vs actual boost but without taking the reduced power into account. It becomes a self-fulfilling prophecy and triggers the full code with CEL and limp mode after a certain distance/time is reached.

 

[Carcinogenx]

Welp, for 1, the search option here is poopie. 2, searching this forum using Google is hit and miss at best. In the time it took you to say "Google it you could have instead been helpful. But, from experience this is what most people get from the been here done that crowd. Which is also a contributing factor of this forum being nearly dead. Just my .02

I recently bought a 2006 Mini Cooper and the forums for Mini have millions of posts, yet I can find whatever I'm looking for pretty easily. I agree that it is tough to find info here on this forum. And you're right, there are lots of dead posts here where people asked for help and the only reply is to "keep searching". It wastes everyone's time.

 

[Carcinogenx]

There might be a pending P0299 code which won't trigger the CEL but will limit boost to around 5 psi for as long as it's pending.

Check for the code with a scanner and clear it if it's there and see if the symptom persists.

The diagnostics on this code are incredibly stupid. While the pending code is there, it continues to monitor expected vs actual boost but without taking the reduced power into account. It becomes a self-fulfilling prophecy and triggers the full code with CEL and limp mode after a certain distance/time is reached.

Thank you for the suggestion. I used my Diablosport to scan the car and it didn't show any codes. I honestly don't think I'm getting any boost at all when this occurs. Anything else I can check? I remember reading up on the wastegate and blowoff valve but the issues people were having were not like mine. Maybe I'll revisit that and dig deeper into posts.

 

[RMinNJ]

When I have a similar issue..Ultra Guage would see the codes. I forget which codes. Could be overboost or underboost. Usually turning the car on/off put me back on boost until it happened again. Best to datalog and describe the problem to BNR... he mentioned the wastegate not being able to hold high boost. My tune seems dialed back so this doesnt happen but im ok with it.

 

[Carcinogenx]

When I have a similar issue..Ultra Guage would see the codes. I forget which codes. Could be overboost or underboost. Usually turning the car on/off put me back on boost until it happened again. Best to datalog and describe the problem to BNR... he mentioned the wastegate not being able to hold high boost. My tune seems dialed back so this doesnt happen but im ok with it.

Thank you for the tip.
I did more research yesterday and decided that I'm going to get the BNR wastegate. You brought up a good idea too, I can data log a drive tomorrow morning. It's only 50 in the morning, but that's cold enough to trigger the issue.
A couple months back, before I had this issue, I asked BNR for a more aggressive tune and Jerry did not disappoint. He pushed it to the limit, but now its either on or off, full boost or nothing. It is impossible to drive my Sonic smooth, and that gets annoying. The power is nice, but I need to have him dial it back a bit. Maybe the combination of the two will work.

 

[Carcinogenx]

An update

It happened yesterday and I had my Diablosport ready. No CEL but I got two codes.

P0238 - Turbocharger/Supercharger boost sensor A circuit high
P2227 - Barometric pressure sensor A circuit range/performance

I read up on these codes and followed the advice of going back to my old, mild BNR tune. I haven’t had any issues so far. Going to drive my Sonic as much as possible next week.

 

[wasteoffilm]

Having the same issues, no fix yet, not in any real hurry to fix it.

The BNR actuator is not a cure for this, for me, this started happening when I installed it, and restored my lost boost pressure. My old actuator was only allowing me about 17 psi continuously. Now, under the right conditions, it spikes to 23.5 and goes into soft limp mode.

Originally, it would present itself after a few seconds of heavy throttle, but after some wastegate duty cycle modifications, it now takes 10-15 seconds continuous heavy throttle to present those codes. Heavy, such as pulling up a long hill/ramp/dyno pull in a higher gear, 3+.

The issue, as I understand it, is the wastegate outlet is too small, and can't bleed the excess pressure fast enough.

The quick cure, is to "Clear DTC" as needed to restore power. I use either my Autocal, or the Torque app and my OBD2 adapter, and can do this on the fly.

I'll try and get another log going today, but the roads are all wet, and my summer tires are worn out, no grip.

 

[EyeluvSmegma]

An update

It happened yesterday and I had my Diablosport ready. No CEL but I got two codes.

P0238 - Turbocharger/Supercharger boost sensor A circuit high
P2227 - Barometric pressure sensor A circuit range/performance

I read up on these codes and followed the advice of going back to my old, mild BNR tune. I haven’t had any issues so far. Going to drive my Sonic as much as possible next week.

I dont recall anyone having this issue other than BNR tuned cars. Maybe this is why ZZP doesnt tune past 17psi? IDK, but im exploring that option.