Jump to content
LegacyGT.com

Boost Creep, Fuel Cuts, and Angry Wives


Recommended Posts

Hey there, Hi there!

 

I’m hoping to get a decent thread going. Here goes...

The victim: My 2005.5 Legacy GT with 5EAT and 125,000 miserable miles.

The crime: A p2044 CEL with a fuel cut and repeated foul language.

The perpetrator: High flow panel filter, after maf silicone hose, Mishimoto Turbo Inlet, AVO TMIC, silicone throttle body hose, Turbo XS BPV, Invidia divorced wastegate catless down pipe, no name catback exhaust, Invidia solid up pipe, COBB Accessport running a stage 2 off the shelf map.

 

The Verdict: I hit 20 psi the other day and had a fuel cut and a p2044 code. Made me pee a little. I know a protune would be reasonable, but I’m trying to exhaust other avenues. I asked COBB for a low wastegate duty map this morning and they told me they wouldn’t because their tunes are for “catted downpipes only!” I personally think they should fu€k themselves with a bayonet, but what do I know? Please feel free to chime in with ideas, criticisms, prior experiences, or cookie recipes. Keep in mind I am a machinist, a former mechanic, and a lunatic. Thank you!

Link to comment
Share on other sites

Are you consistently overboosting, i.e. has this happened more than once? Is it colder now where you are than normal? If the car has been fine otherwise, reset the ECU and see if it overboosts again. Honestly, if you need a low-wastegate map, just tell them you have a catted downpipe and see if they give you the map. I think it's ridiculous they don't just have the maps available for download on their website (and that ATR is behind a paywall now). The stage2 map, IIRC, targets around 18psi, so 20psi isn't a massive overboost, depending on environmental conditions.

 

Also, "perpetrator" :)

Link to comment
Share on other sites

Are you consistently overboosting, i.e. has this happened more than once? Is it colder now where you are than normal? If the car has been fine otherwise, reset the ECU and see if it overboosts again. Honestly, if you need a low-wastegate map, just tell them you have a catted downpipe and see if they give you the map. I think it's ridiculous they don't just have the maps available for download on their website (and that ATR is behind a paywall now). The stage2 map, IIRC, targets around 18psi, so 20psi isn't a massive overboost, depending on environmental conditions.

 

Also, "perpetrator" :)

 

The stage 2 93 octane map targets 16 or 16.5psi, if I remember correctly, and it only hits that in a big torque spike in the midrange. On a colder day mine usually ends up spiking to 17 or 17.5 before dropping down and holding pressure somewhere in the mid-low 16psi range.

 

When did they stop giving out accesstuner? If I remember correctly all I had to do was provide them the serial number for my accessport and they sent me an installer.

 

Assuming it's just a matter of too much exhaust flow, pulling a bunch of wastegate duty cycle should be all that you need to do, although honestly if you aren't planning to throw more parts at your car in the near future, just get an etune because the OTS tunes are safe but pig rich.

Link to comment
Share on other sites

Yea, My iphone’s auto-correct must be Slavic. The target boost is 16.5 and yes, it is due to colder temps. The douche at COBB was jerking me around how their “generic” maps are unsafe for my setup and will lead to my engine’s demise. When I reset my ecu it eventually hits the fuel cut again. Damn thing is hitting 20-21 psi in the blink of an eye. Pretty sure I have a head gasket on it’s way now as well. I checked the restrictor pill hose and all the crap by the boost controller. Didn’t find any leaks. Think I could “adjust” the wastegate actuator to compensate?
Link to comment
Share on other sites

Otherwise could someone advise a decent, cheap etuner? I’m 45 minutes south of Milwaukee if someone knows of a reputable tuner in the area who doesn’t charge a ton. And please don’t say Chicago. We don’t speak of such places where I’m from.
Link to comment
Share on other sites

Wastegate actuator is non adjustable on any of the IHI turbos. You could go with an aftermarket like AVO and that would give you adjustability. You're obviously overboosting and my first guess would boost controller is bad.

 

The Invidia catless dp is notorious for boost creep. How would the ebcs be able to compensate for this? Not saying it isn’t bad. Just don’t think that will help if the map I’m running is a moderate wastegate duty.

Link to comment
Share on other sites

Time to re-evaluate your decision-making process. You've spent 2 grand on shiny aftermarket parts that don't gain you a lick of performance on stock fueling & turbo, you're clearly aware that the combination of all the aforementioned bolt-ons is about to blow your engine, and you are still, somehow, clearly determined to avoid the most important step of the performance improvement process. A proper tune will optimize your performance, extend the life of your engine, and basically save you from yourself. All for a tiny fraction of what you've wasted so far. Unfortunately, a tune does not come in purple to impress the fanboyz at StanceWarz, but maybe a sticker is not out of the question.

Cryotune and Tuning Alliance can't be beat, and e-tune prices are extremely reasonable.

Link to comment
Share on other sites

Time to re-evaluate your decision-making process. You've spent 2 grand on shiny aftermarket parts that don't gain you a lick of performance on stock fueling & turbo, you're clearly aware that the combination of all the aforementioned bolt-ons is about to blow your engine, and you are still, somehow, clearly determined to avoid the most important step of the performance improvement process. A proper tune will optimize your performance, extend the life of your engine, and basically save you from yourself. All for a tiny fraction of what you've wasted so far. Unfortunately, a tune does not come in purple to impress the fanboyz at StanceWarz, but maybe a sticker is not out of the question.

Cryotune and Tuning Alliance can't be beat, and e-tune prices are extremely reasonable.

 

Okay. I didn’t spend two grand on anything. So don’t make assumptions. Everyone has been plenty helpful prior to your prissy bitch comment. Most of the shit was on the car when I bought it. The previous owner spun a bearing so the car had a used motor and a brand new turbo with all the crap bolted on it from the previous engine. The only thing I added was the turbo inlet ($185) because the stock one started to tear, and the AVO TMIC (used $250) because the oem was leaking badly. Neither part is shiny. And my decision to buy such was based on fixing the garbage the engineers had there in the first place, cheap plastic crap! Therefore my decision making is exactly where it should be. And the fueling isn’t “stock.” Atleast the fuel map isn’t. Learn to read and comprehend before you pass judgement. And as for stance.... my car sits on factory size wheels with 06 Spec B Bilsteins and stock springs. The only thing purple is my d!@k.

Link to comment
Share on other sites

So I’m guessing an etuner would have me give a list of modifications and then data log things such as load, afr, maf voltage, boost, knock, and such. Then they build a tune around the information given. I would then upload the tune and give it a go while monitoring a few parameters and then send them a data logged WOT pull. Does this sound about right? We have temperatures around here ranging from over 100 degrees in the summer to almost -30 in the winter. Correct me if I’m wrong, but one map probably wouldn’t suffice for both extremes.
Link to comment
Share on other sites

So I’m guessing an etuner would have me give a list of modifications and then data log things such as load, afr, maf voltage, boost, knock, and such. Then they build a tune around the information given. I would then upload the tune and give it a go while monitoring a few parameters and then send them a data logged WOT pull. Does this sound about right? We have temperatures around here ranging from over 100 degrees in the summer to almost -30 in the winter. Correct me if I’m wrong, but one map probably wouldn’t suffice for both extremes.
The tuner would send you a "safe" or "base" map that is the closest fit to your current setup. Then you would data log while driving some repeatable test cases, that include WOT. They will then adjust the map based on the logs. This process is repeated several times until the tuner is happy with the result.

 

The map includes compensation tables that adjust for intake air temperature and many other factors. So, a properly done tune should work for Summer and Winter, sea level to Colorado mountains.

 

It would be more common to change the map if you changed the fuel you were running, i.e. higher or lower octane.

Link to comment
Share on other sites

The tuner would send you a "safe" or "base" map that is the closest fit to your current setup. Then you would data log while driving some repeatable test cases, that include WOT. They will then adjust the map based on the logs. This process is repeated several times until the tuner is happy with the result.

 

The map includes compensation tables that adjust for intake air temperature and many other factors. So, a properly done tune should work for Summer and Winter, sea level to Colorado mountains.

 

It would be more common to change the map if you changed the fuel you were running, i.e. higher or lower octane.

 

That shouldn’t be a problem then. I try to run 93 octane preferably without ethanol, but it’s almost impossible to find around here. Only two gas stations within 20 miles of me. So it would be for 91. I’m very unhappy with the COBB response. Guess an etune it is.

Link to comment
Share on other sites

Trace your boost control vacuum line from the actuator forward under your intake manifold. There is a coupler right as it passes over the intake and when it pops off your boost goes up insanely fast. I ran into this a couple weeks ago. I have a picture somewhere around here. It’ll probably take a flashlight and careful searching to trace the line. It’s also a pain to get to to reconnect.
Link to comment
Share on other sites

Trace your boost control vacuum line from the actuator forward under your intake manifold. There is a coupler right as it passes over the intake and when it pops off your boost goes up insanely fast. I ran into this a couple weeks ago. I have a picture somewhere around here. It’ll probably take a flashlight and careful searching to trace the line. It’s also a pain to get to to reconnect.

 

Second this, checking all your boost control lines should be your first step. I had a fitting melt causing similar issues. This will typically show up as overboosting right at spool up or the lower mid range. High rev range boost creep is probable wastegate flow related.

 

You can also pop the line off the compressor housing and blow into it. If it dosent hold pressure with the motor off, you have issues in your boost control plumbing.

Link to comment
Share on other sites

I had this same issue last winter, and it ended up just being that the actuator arm was stuck and wasn't opening, causing overboost to 21 psi and then the CEL. Was able to spray some WD-40 on it and haven't had an issue since. Just my two cents, but quick and easy to try. Best of luck to ya.
Link to comment
Share on other sites

Yea, My iphone’s auto-correct must be Slavic. The target boost is 16.5 and yes, it is due to colder temps. The douche at COBB was jerking me around how their “generic” maps are unsafe for my setup and will lead to my engine’s demise. When I reset my ecu it eventually hits the fuel cut again. Damn thing is hitting 20-21 psi in the blink of an eye. Pretty sure I have a head gasket on it’s way now as well. I checked the restrictor pill hose and all the crap by the boost controller. Didn’t find any leaks. Think I could “adjust” the wastegate actuator to compensate?

 

Sorry guys. I appreciate the help, but as the post above shows I checked those lines including the one with the little brass restrictor pill. I replaced all of them two summers ago with factory hoses and a solid aluminum t fitting the same size as factory. I had the original plastic t fitting crack on me. I just love the plastic! Plastic is for holding groceries and dildos. Keep it off our engines!

Link to comment
Share on other sites

It's hard to tell to what extent someone has checked things from a sentence or two. The reason why I asked was that if you are getting to ~20psi and fuel cut off with almost no effort that indicates the wastegate is not being managed by the boost controller. The most common source of that is a hose off or leak; after that is is likely the boost controller itself. This is not something you want to "fix" by adjusting the wastegate actuator, there is a problem that you need to track down. These kind can be a real pain in the rear. I thought I had double checked all my hoses as well when I found the vacuum connector smack dab under the middle of the intake. Just trying to make suggestions based on my experiences.
Link to comment
Share on other sites

It's hard to tell to what extent someone has checked things from a sentence or two. The reason why I asked was that if you are getting to ~20psi and fuel cut off with almost no effort that indicates the wastegate is not being managed by the boost controller. The most common source of that is a hose off or leak; after that is is likely the boost controller itself. This is not something you want to "fix" by adjusting the wastegate actuator, there is a problem that you need to track down. These kind can be a real pain in the rear. I thought I had double checked all my hoses as well when I found the vacuum connector smack dab under the middle of the intake. Just trying to make suggestions based on my experiences.

 

I appreciate your input. I thought the same. There is one thing I did forget to mention. My fuel injector duty is much higher than I feel it should be based on my modifications. I’ve seen it hit as high as 96%. The thing is most people I’ve mentioned it to think my modifications shouldn’t be maxing out the stock injectors. My understanding was usually a bigger turbo warrants larger injectors, but mine is the factory IHI. Maybe I should flow test them or perhaps check to see if the in tank filter is clogged. Not a project I would look forward to. I’ve considered putting an STI fuel rail on the car. It was warmer a few days ago and I wasn’t seeing any boost creep. But it still isn’t right. I’m looking for bubbles in the overflow tank because I did smell coolant the other day, but couldn’t find the source. I have a funny feeling I have a head gasket issue developing. I don’t have a garage and I don’t have the time or the will to pull a motor in 30 degree weather. I’m not familiar enough with these engines to know if a head gasket failure could be contributing to my issue. I have a compression tester but if the leak isn’t significant enough that might not show anything. I’m going to stop at my buddy’s house tomorrow and have him give it throttle with the accessories running to see if any bubbles show up in the overflow tank. This is what I hate about the lack of a mechanical throttle cable.

Link to comment
Share on other sites

Check your vaccum hose on the fuel pressure regulator is tight on both ends. I had mine start to leak and want to slip off and my car started to do weird bucking. Do you have a fuel pressure gauge to see if you are getting adequate pressure to the rail(s)? Do you have an original fuel pump or is it aftermarket.

 

good luck.

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