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Hezig
DSM Regular
Joined: Thu Oct 06, 2011 10:13 pm Posts: 93 Location: East LA
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Losing power while accelerating under load
Hey guys, Got a bit of a problem here. Whenever I accelerate, the car will suddenly lose power, not like stall, but acceleration. And then after a few seconds it will kick back in again. It will sometimes do it once, or sometimes it will do it over and over for a few seconds. Its pretty bad. It jerks like when you're teaching someone to drive stick. Also, I'm idling really high I'm at 1000-1100. And just a few weeks ago I was at a perfect 750. And my O2 sensor is taking a crap, I'm running way to rich.
So far I've done the following. Changed plugs and wires, plugs are at .28. I've done a boost leak test, even rebuilt my tb along with adjusting the tps and biss. Ran a full tank of seafoam, and changed the gas filter (worst fucking job ever... you know how hard it is to get a 15yr old bolt seized out in that little space?
I thought it might be a gas pump problem, so I did a few WOT pulls, and no loss of power or misfire.
Anyone got any ideas on what could it be? I'm taking it to my mechanic on Friday, but quite honestly I prefer to try and fix it myself.
Thanks, Hezig
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Mon Jan 07, 2013 12:51 am |
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805dsmALEX
Senior Member
Joined: Tue May 22, 2007 7:22 pm Posts: 689 Location: Oxnard Shores
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Re: Losing power while accelerating under load
If you did all that, check the fuel pressure, with an actual guage ,
_________________3kgt VR4
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Tue Jan 08, 2013 8:32 pm |
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Wally
Senior Member
Joined: Wed Feb 18, 2009 1:59 pm Posts: 2238 Location: Los Angeles 90006
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Re: Losing power while accelerating under load
Sounds like a dead knock sensor. Similar to the issues my spyder has. Mine does it under load as well like at low rpms and in every gear. It feels like im towing something lol
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Sat Jan 12, 2013 1:15 pm |
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Hezig
DSM Regular
Joined: Thu Oct 06, 2011 10:13 pm Posts: 93 Location: East LA
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Re: Losing power while accelerating under load
I couldn't get to the pressure on the fuel... but. I did hear knocking sound under the timing belt... so limping and all I turned left hard, pedal pressure was the same, and I could go into neutral. And back into gear with no problem. Gonna go ahead and check the knock sensor along with the fuel pressure, then I'll report back what I find.
Thank for the help guys.
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Sat Jan 12, 2013 6:18 pm |
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turboawdfanatic
Moderator
Joined: Tue Aug 14, 2007 2:39 pm Posts: 3013 Location: La Habra
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Re: Losing power while accelerating under load
Losing power while acceleration sounds like either real or phantom knock. If it's phantom knock it could be a dead knock sensor. If it's real knock you need to datalog to see what's going wrong. Are you running stock boost levels or do you have a boost controller? If you've raised the boost try dialing it back to stock to combat the knock and see if the hesitation is still there.
From the things you listed it sounds like you have more than one issue. Search dsmtuners.com for idle issues.
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Sun Jan 13, 2013 5:27 pm |
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Hezig
DSM Regular
Joined: Thu Oct 06, 2011 10:13 pm Posts: 93 Location: East LA
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Re: Losing power while accelerating under load
I'll go ahead and lower boost. I'm running 15 psi on a t25. I'll set it to stock.tomorrow I'm checking fuel pressure, changing my O2 sensors and check what codes the car is throwing, that should rule out the knock sensor and any other thing I might be missing.
Thanks again.
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Mon Jan 14, 2013 2:27 am |
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-red97rum-
Senior Member
Joined: Mon Aug 10, 2009 9:57 am Posts: 1077 Location: Ontario, CA [IE]
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Re: Losing power while accelerating under load
Sounds to me like it could be a boost leak. The sudden change in idle leads me to believe it's sucking in unmeterer air causing the idle to raise. Good luck and make sure to let us know what the issue was once you get it taken care of. A dead knock sensor locks timing at around 9* if I remember correctly, at least it does on a 1G.
Cheers.
_________________-Dustin 1992 Tsi Auto Swapped 10.67@126mph
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Tue Jan 15, 2013 4:03 pm |
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Hezig
DSM Regular
Joined: Thu Oct 06, 2011 10:13 pm Posts: 93 Location: East LA
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Re: Losing power while accelerating under load
Update: Finally got around to get the obd1 hooked up. As expected, my O2 sensor was bad. And also my MAS is bad which explains the rough idle, the jerking at lacceleration but not at WOT.
Now I just need to finally make time to pick up the SMIC and get rid of all the major boost leaks.
Last thing, can spraying Carb cleaner into the MAS sensor mess it up? That was the last time I ever touched the MAS, when I did the boost leak test. After that the jerking started.
Thanks
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Tue Jan 22, 2013 2:48 pm |
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gsttunner
Senior Member
Joined: Mon May 28, 2007 10:17 pm Posts: 170 Location: south central
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Re: Losing power while accelerating under load
Carb cleaner will kill a mass sensor
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Tue Jan 22, 2013 3:15 pm |
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Hezig
DSM Regular
Joined: Thu Oct 06, 2011 10:13 pm Posts: 93 Location: East LA
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Re: Losing power while accelerating under load
Then there we go lol...
Edit: actually I checked the can and it wasn't carb cleaner. I guess it was just coincidence that the MAS took a shit after I put it on either way I'll swap those and check to see if my problems are gone.
Thanks
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Tue Jan 22, 2013 3:52 pm |
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