reg Posted June 14, 2005 Share Posted June 14, 2005 I'm new to turbos and the way mine behaves on acceleration puzzles me. My 5MT GT has 2000 miles (3000km) on it. I have read the posts on "stuttering" and have noticed my gt does seem to stumble at about 2500 rpm. I presume thats what is meant by stuttering. That's not my concern. I was wondering if the problem I describe below is something different. The problem I am curious about occurs when I apply heavy throttle, especially in second gear. Instead of coming on smoothly as usual , (rrrrrrrrrrrrmmmmmmmmmmmmMMMMMM *shift*) the power sometimes comes on in a series of short surges until I get up to 5000 RPM or so (rrrrmmmmmmmmmm-rrrrrimm-rrrrrimm-rrrrrimm-rrrrrimm-rrrrrimm-rrrrrimm-mmmmmmmmmMMMMMM *shift*) There is always plenty of torque but it comes on in little surges. No stutter, no miss or hiccup, just a pulsing, surging sensation as the power comes on unevenly. This happens from time to time when I accelerate smoothly from a roll at to full throttle as well as when I just nail it to the floor. It doesn't seem to matter if the car is warmed up. Can anyone tell me what this is, why it occurs, and whether I should be concerned about it? Link to comment Share on other sites More sharing options...
LEGA-C-YA Posted June 14, 2005 Share Posted June 14, 2005 I don't think that I have ever felt that type of hesitation on mine. Above 3000 rpm it should pull smoothly and evenly right to redline. Perhaps a trip to the dealer is the best course. Maybe you could drive another Legacy to see if you feel a difference Link to comment Share on other sites More sharing options...
chohakai Posted June 14, 2005 Share Posted June 14, 2005 Most likely due to ECU pulling timing due to knock. It's protecting your engine at the expense of performance. I used get that in my WRX until I stopped buying shitty gas at getto gas stations. A quick way to find out is to dump in some good gas along with some octane booster. It should go away. Fred Link to comment Share on other sites More sharing options...
melayout Posted June 14, 2005 Share Posted June 14, 2005 Yeah if you have a full tank, just dump some octane booster in or let it idle/drive around for a while, then fill her up with the highest octane gas you can find. I keed I keeed Link to comment Share on other sites More sharing options...
neelnug Posted June 14, 2005 Share Posted June 14, 2005 honestly my car feels just like that. Im using 94 octane with no results. It will be going into the dealer soon. Im thinking the AP might fix this. Link to comment Share on other sites More sharing options...
YBNormal07 Posted June 14, 2005 Share Posted June 14, 2005 As a previous owner of both a WRX and STi, welcome to the subura of america.....land of the intermitant power application. They all do it, it is anoying, and you think yours is the only one that does it until you see it somewhere like here. It is always more noticable in warmer weather by the way, which is why we keep seeing more posts on it now. In my experience, the only thing that gets rid of this is proper engine management. Subaru tunes our ECU so conservatively, sometimes I think the a/f ratios are fighting themselves. Almost it's going...yes...yes...ok..ok...wait....ok go ahead...ok..ok..no wait..... On my LGT, I've mapped out 4 locations where it occurs...2200, 2500, 2800, and somwhere around 35-3800. After that, it's smooth sailing. Link to comment Share on other sites More sharing options...
eles1 Posted June 14, 2005 Share Posted June 14, 2005 It is always more noticable in warmer weather by the way, which is why we keep seeing more posts on it now. In my experience, the only thing that gets rid of this is proper engine management. Subaru tunes our ECU so conservatively, sometimes I think the a/f ratios are fighting themselves. Almost it's going...yes...yes...ok..ok...wait....ok go ahead...ok..ok..no wait..... On my LGT, I've mapped out 4 locations where it occurs...2200, 2500, 2800, and somwhere around 35-3800. After that, it's smooth sailing. YES!!! And with the AC on, it's even more pronounced. I've also noticed that mine hesitates/stutters seemingly at the same rpm every time. I haven't recorded those rpm values yet, but the ones you have above seem about right. Also, it seems to vary slightly depending on which gear I'm in. You mentioned that your WRX and STI both had similar issues, but were they as pronounced as your LGT? Were your previous Subarus better, worse, or pretty much the same with respect to the "stuttering"?? Link to comment Share on other sites More sharing options...
YBNormal07 Posted June 14, 2005 Share Posted June 14, 2005 The WRX was about the same as the LGT, except it was a bit earlier in the boost cycle. The STi only had one noticable "judder" spot that I could detect. Cobb took care of it no problem. Will definitely be going on my LGT. Link to comment Share on other sites More sharing options...
eles1 Posted June 14, 2005 Share Posted June 14, 2005 The WRX was about the same as the LGT, except it was a bit earlier in the boost cycle. The STi only had one noticable "judder" spot that I could detect. Cobb took care of it no problem. Will definitely be going on my LGT. Cobb AP Stage 1 helps significantly with the stuttering, but doesn't get rid of it entirely. Stage 2 may help even further, not sure. Link to comment Share on other sites More sharing options...
OCDetails Posted June 15, 2005 Share Posted June 15, 2005 I'm sorry, but its bullshit that I have to spend $650 dollars to buy an AP to fix a problem that shouldn't even be there. My car does the exact same thing and its got 3000 miles on it right now. Since there isn't anything the dealership is going to do about it, there isn't even any point in taking it in. I don't have the time to mess with that kind of stuff. _________________________________________ “Cleanliness becomes more important as godliness becomes more unlikely.” O C D E T A I L S . C O M OCDETAILS BLOG Link to comment Share on other sites More sharing options...
Deer Killer Posted June 15, 2005 Share Posted June 15, 2005 This is what I'd do: Hold you speed with your left foot on the brakes in 2nd gear at around 2000rpms with the throttle to the floor until you hear the turbo spool (1-2 seconds), let go of the brake and observe what it does until you hit redline. If you see problems here I'd say there's something wrong somewhere. Link to comment Share on other sites More sharing options...
eles1 Posted June 15, 2005 Share Posted June 15, 2005 I'm sorry, but its bullshit that I have to spend $650 dollars to buy an AP to fix a problem that shouldn't even be there. My car does the exact same thing and its got 3000 miles on it right now. Since there isn't anything the dealership is going to do about it, there isn't even any point in taking it in. I don't have the time to mess with that kind of stuff. I agree 100%. It's a bit discouraging to know that if you take it back to your dealer, you're probably just going to get one of their "canned" responses ("that's normal", or "can't reproduce") with no resolution whatsoever. Still, I probably will mention it to my dealer next time I'm in for service just so I can have it on record if they happen to come out with a fix sometime after my warranty has expired. Link to comment Share on other sites More sharing options...
dvanb08LGT Posted November 15, 2017 Share Posted November 15, 2017 My 08 LGT is doing something similar under heavy acceleration light acceleration and even just normal driving I could be cruising along and I've noticed at like 2500 rpm ot will start pulsing drop to 2200 back to 2600 and back and forth. I have no mods done to the car could this also be the ecu programming? At low speed light acceleration it's a pretty decent pulse at heavier acceleration most of the time and more light but you can feel the random cuts in power but sometimes it does pulse pretty hard under heavy acceleration. Been trying to figure this out for days car only has 48k on it no engine light or anything just random power pulsing. Also sometimes it just seems like it doesn't have the power it should even when it's not pulsing and other times it takes off like a bat outa hell. Link to comment Share on other sites More sharing options...
Infosecdad Posted November 15, 2017 Share Posted November 15, 2017 Highly recommend starting a new thread, this one is over 12 yrs old... Link to comment Share on other sites More sharing options...
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