Not sure if I have a similar issue as this guy --> http://mnsubaru.com/forums/showthre...y-do-have-a-boost-leak...?highlight=hose+leak But during the drive into work today I was noticing pulsing while in boost. Kept it below boost for the rest of the drive but has anyone else noticed this during our current heat wave we're having? Could it be heat/humidity related or do I have a leak somewhere? '07 wrx, sti intercooler, bullwinkle tune, vf-39, yada yada I'll confirm the pulse on the drive home tonight but let me know if you have any ideas and where to start looking. Could this be a temporary issue and it go away or do I surely have a leak or what not? Thanks all
Hmmm... for me it wasn't a pulse. Just a dramatic, linear power loss. What does this pulse feel/sound like, exactly?
If in doubt do a boost leak test. Heat and humidity can also cause problems, but these things compound as well. If you have smaller boost leaks that aren't quite bad enough to be noticeable, then add screwy weather to the mix it may push you over the threshold for poor running.
Anyway to easily do a boost leak test in my own garage? Guessing I just need to pressurize the system with my compressor somehow?
I noticed a power loss these last couple days. Last night driving a buddy home I was in full boost and it didnt have its normal "throw ya in your seat kinda power." I mostly blamed it on the heat outside. :biggrin:
I have a boost leak tester we could bolt up quick in my driveway if you want. I am located in Prior Lake. orrr you can make one, they are simple. View attachment 25072
That looks pretty cool. I was just looking at something similar. Might just build one up myself, not a bad idea to have one around the shop. Thanks!
Here's a link to Peaty's guide to check the rubber ring on the OEM bypass valve. Not sure if it applies for your setup, but it's worth checking out. http://www.scoobymods.com/high-mileage-recirc-valves-worth-t12353.html
If you build a tester, I recommend adding an inline regulator instead of the plane coupling (this is assuming your compressor is not conveniently located right next to your car). You can get a 12" flexible piece and regulator which makes connecting it really easy and also allows precise control of pressure in the system. It's an extra $5-$10, but really worth it IMHO.
Did you take off your intercooler and check to see if you had the same issue I fixed on my car and the car in the link you shared? Do you have a boost gauge? If so have you noticed anything different. Keep in mind this heat does affect how your car will drive.
Have not yet checked under the intercooler but have that on the list(remember seeing your thread) Yup, have a boost gauge and will check that on the way home, soon thank gawd! Yeah, hoping its just the heat/humidity. I'll report back with my findings after the drive home Thanks as always for the input everyone.
With the boost gauge the main thing i noticed..... 1. The idle was higher... the vacuum on my car was not sitting @ -20PSI like it normally does. I also noticed a weird surge when the car was first started, it would idle hard for a while... but that was more noticeable when it was colder out. 2. I was not hitting peak boost with one boost leak, but another the car/turbo was able to make up for the leak.... so peak boost isn't always the best indicator. Have you thrown any CELs? I did throw a few CELs with my first two boost leaks. It is really crappy weather to do it this week but if you need a hand i am happy to try and help. I don't know a ton about cars like some people on here... but I have fixed a few leaks myself. I was also able to help out SurlyOldMan with his leak. Let me know
Update- Drive home last night was pretty much the same and I was melting so I didn't push it too hard. This morning I noticed the stutter/pulse during low revs that crepped into boost but really got on it a couple pulls through third and it seemed to be holding much better. Almost feels like something is sticky from the humidity and gets stuck some times. Either way after a few more on ramp pulls its feeling as good as it always has. So as of now i'm chalking it up to heat and humidity. I'm going to drive it as is till the weekend at which point i'll see if I need to dig into her. Thanks for offer punk, i'll keep you posted. I'm thinking it wouldn't be a bad idea to test for leaks anyway, couldn't hurt really. Plus its been while since i've gotten to get a lil dirty working on my own car
Have you taken any logs? Kinda sounds like youre knocking, pulling timing, and the ecu is slowly learning around it. Check for knock (realtime and historical)
You just had to go and say something to freak me out. Damn you No logs taken, how does one take logs. I might have access to a code reader that can take logs, same thing? Any reason why this issue would show its ugly head? Guess i'll check my oil level too before heading home today. Wouldn't there be other signs if I was knocking? Also no check engine lights on
You need a laptop and need to download romraider. You'll also need a Tactrix cable to hook the laptop up to your car. You may be able to check realtime info with a code reader but more than likely you'll want to go the romraider route.
Well with the ambient temps and humidity the way they are its very possible that the current conditions exceed the normal thresholds of your current tune... especially if you ever stop... with a tmic i wouldnt be surprised if your iats are over 160... probably double what you were tuned on. No need to worry. The ecu logic is built to detect and react to knock.... just dont go hammering on it until you know for sure you arent knocking.
Thanks man, maybe i'll shoot a link to my thread to bullwinkle and see what he has to say. I'll keep a light foot for a bit and see how it plays out. So you're saying I need a front mount, larger injectors, bigger turbo, bigger fuel pump, etc right? I just wanna be sure I have this correct when I tell the wife.
Yeah, pretty much. Of course there will be the STi 6MT swap, clutch, bushings and mounts to handle the required fixes above. And of course a BBK to make sure you don't end up needing body work too.
Well i've gotta do my 60k transmission fluid change so might as well just install a pre-filled STi 6MT. Then at least I don't have to mess with that dreaded torx bolt.
Car is back to normal again, no pulsing or shudders. Note to self, car does not like hell on earth like driving conditions. Thanks for the input everyone.
Bumping this thread from the dead...I think I may be experiencing a similar issue, but since I was just tuned this weekend I don't have much experience driving around on my current tune. Essentially, I was hitting peak boost of 18-19 psi on Sunday/Monday (was tuned Sunday morning) and today I am only seeing about 16psi. Chalk it up to heat/humidity? I thought I'd wait until sundown to drive it after it cooled down but I'm still only hitting about 16psi...is this weather hot enough to be experiencing this? I won't be able to get to anything until this weekend, so hopefully it just sorts itself out when we are hitting highs of only 60's later this week
I figured you'd chime in Probably a stupid question, but is this a sort of failsafe built into the tune based on intake temps?
cold air = dense hot air = dry there are compensations in the tune to add some more wastegate duty cycle to help maintain the boost at a target level, but it's based off intake air temperatures in the maf sensor. if you really want to blow hotter air out of that little td04 on a hot day like this, bring it by lol...i just wouldn't recommend it.
It's not that I want to, it's more about just having the understanding of 'why'...ya know? Either way, I'll just keep my eye on everything. Btw...I can't help but ready your signature as an ending to every one of your posts
