Jump to content
LegacyGT.com

Identifying power problem


Recommended Posts

So I'm really dumbfounded as to what this is. It's similar to the shutter effect? People are calling.

 

Car just has no power to the wheels in second gear below 3500 rpm. Once it goes past that I get a huge flush of power (what I'd expect it to be but gradually build up, not on/off). What's weird if theres nothing "odd" about my rpm curve, and I'm at full boost BEFORE the 3500 mark. It's almost like a gear slip? or something I'm not sure any ideas?

 

Again, power is almost off/on until 3500 rpm in second gear, and I dont think it's just boost lag as I'm already at 15lbs of boost before 3500 rpm. In third gear I don't have this problem. There's no boost leak. I mentioned the "hesitation" to my tuner a few times in our back and forth emails but it wasnt' really addressed and I'm outside my 1 month window (bren tuning). I can tell you that I'm on a extremely low wastgate as I had boost creep issues and over boosting in second

 

Any input would be valuable and greatly appreciated.

 

MODS:

Magnaflow cbe

Invidia catted dp

cobb intake+box

grimmspeed ebcs

Bren Tuning e-tune

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

Link to comment
Share on other sites

You think its the timing belt slipping? (I've never had to deal with one so Idk what it feels like slipping) Wouldn't it do it in all gears though?

 

No, not the actual belt itself. The ECU is pulling timing because it's detected an issue where it's programmed to do so. Most likely culprit is knock. When there is knock or misfire, the ECU pulls timing. Your timing belt isn't slipping; if it were, you would be experiencing overall rough running symptoms.

Link to comment
Share on other sites

No, not the actual belt itself. The ECU is pulling timing because it's detected an issue where it's programmed to do so. Most likely culprit is knock. When there is knock or misfire, the ECU pulls timing. Your timing belt isn't slipping; if it were, you would be experiencing overall rough running symptoms.

 

Wouldn't the tuner have seen the knock events in the log? Although I guess for OP, really need to pull logs to see what's going on.

Link to comment
Share on other sites

No, not the actual belt itself. The ECU is pulling timing because it's detected an issue where it's programmed to do so. Most likely culprit is knock. When there is knock or misfire, the ECU pulls timing. Your timing belt isn't slipping; if it were, you would be experiencing overall rough running symptoms.

 

 

Oh gotcha now, thanks for the explaining of "pulled timing"

 

Wouldn't the tuner have seen the knock events in the log? Although I guess for OP, really need to pull logs to see what's going on.

 

he didn't mention it

 

Thought about that after I posted, but, also yes.

 

ya didnt mention anything, and its Bren tuning so if there was you'd think they'd say something.

 

If it were that.wouldnt it happen in third too? I mean there's more of a load on third than second ?

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

Link to comment
Share on other sites

Wouldn't the tuner have seen the knock events in the log? Although I guess for OP, really need to pull logs to see what's going on.

 

Luckily I save all my logs, have a few second pulls I'l check for a knock. ( I know one of the things he had me turn on was knock something)

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

Link to comment
Share on other sites

I'll take a second gear pull log and post it tonight.

 

Anything in particular I should turn on? This is what I have on now(for the tuner before)

 

AVCS In. Left () AVCS In. Right () Boost (PSI) Calculated Load (g/rev) Dyn. Adv. Mult (DAM) Dynamic Adv. () Dynamic Adv. Lrn () Fine Knock Learn () Gear Position (gear) Ignition Timing () Inj. Duty Cycle (%) MAF (g/s) MAF Volt. (V) RPM (RPM) Throttle Pos. (%) Vehicle Speed (mph)

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

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