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10-11-2010, 05:43 PM | #1 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
flat spot in powerband
so i have a 99 rs with an 05 rs longblock.
it still has the 99 rs manifold, egr has an oil pan bolt on it. my problem is a spot on the rev range from 3600 to 4250 where there is a loss of torque that is huge, it pulls till 3600, where it bogs and then it takes off again at 4250. what could be causing this?
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10-11-2010, 06:11 PM | #2 |
Scooby Specialist
Member#: 165749
Join Date: Dec 2007
Location: Detroit, MF'er!
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sure that the longblock isn't an 06 with the AVLS? failing O2 sensor causing CL/OL switching delay? Any CEL history?
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10-11-2010, 08:44 PM | #3 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
it came with the aluminum manifold, and is from an auto. i don't know for sure if it has the alvs heads, but since i was told it was an 05 i would assume not.
but then again i was told it was from a manual and i got it with a flexplate. the most recent CEL i had was a knock sensor, and it happened when standing water from the last rain got in there. i just replaced both O2 sensors with nippon densos approximately 10k ago, and ever since my exhaust tip hasn't had soot on it, so i'm guessing that they are still working. it is possible that something is causing the CL-OL delay. |
10-11-2010, 11:28 PM | #4 |
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region:
MWSOC
Location: Licking County, Ohio
Vehicle:2005 2.5RS Wagon Regal Blue Pearl |
The combustion chambers and pistons are slightly differently shaped. The intake manifold is VERY different (if you're using that off the 05 as well). In all likelyhood, your stock tune is simply really ****ing bad for the block it was never designed for.
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10-11-2010, 11:33 PM | #5 | |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
Quote:
i wonder if i can get it tuned and still pass smog. |
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10-12-2010, 03:43 PM | #6 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
still occurring, anyone have any thoughts?
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10-12-2010, 03:53 PM | #7 |
Scooby Guru
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MWSOC
Location: Minnesota
Vehicle:2004 Forester STI Silver |
A tune will fix the issue.
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10-12-2010, 04:36 PM | #8 | |
Scooby Guru
Member#: 158864
Join Date: Sep 2007
Location: Aussieland
Vehicle:2003 SOHC destroker |
Quote:
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10-12-2010, 07:59 PM | #9 |
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Member#: 157348
Join Date: Aug 2007
Location: OOoOuuUUUGGGHH!!!!!
Vehicle:I Thlammed My Penith in the Car Door |
I had the problem with my MAF. Clean yours.
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10-13-2010, 12:39 AM | #10 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
thanks for all the suggestions guys.
i'll first clean my maf again, and if that doesn't fix it, i'll try other alternatives. interestingly though, when it isn't completely warmed up the problem does not persist, but i think it may be because i'm not as hard on it when it's still a little cold. |
10-15-2010, 02:13 AM | #11 |
Scooby Newbie
Member#: 254417
Join Date: Aug 2010
Chapter/Region:
MWSOC
Vehicle:09 Impreza Peperika |
A bad Knock sensor will cause this, or you could have knock.
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10-16-2010, 06:01 PM | #12 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
during the last rain, a little water got under the knock sensor causing a CEL.
but i reset it and it hasn't come back. this power band flat spot isn't as bad as it was when the light came on, but it is close. could the knock sensor be bad without throwing a CEL? |
10-16-2010, 09:46 PM | #13 |
Scooby Newbie
Member#: 93577
Join Date: Aug 2005
Chapter/Region:
MAIC
Location: Chicagoland
Vehicle:98 Impreza |
I had a knock sensor that was bad and it intermittenly threw a CEL. Either that or the test for the knock sensor takes awhile. It cleared it once itself. Another couple of times I reset the ECU and it took a week or two to come back on. (The car was driven everyday to, so I doubt the knock sensor tests would take that long to finish).
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10-19-2010, 05:09 PM | #14 | |
Scooby Newbie
Member#: 254417
Join Date: Aug 2010
Chapter/Region:
MWSOC
Vehicle:09 Impreza Peperika |
Quote:
yes it could. what can happen is it picks up knock or what it thinks is knock and pulls timming, or you could have a real knock problem. |
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10-20-2010, 05:34 PM | #15 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
next tank i will run premium grade and see if that makes a differance.
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10-20-2010, 08:58 PM | #16 |
Scooby Guru
Member#: 158864
Join Date: Sep 2007
Location: Aussieland
Vehicle:2003 SOHC destroker |
it won't.
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10-21-2010, 02:38 AM | #17 |
Scooby Newbie
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Vehicle:09 Impreza Peperika |
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10-22-2010, 03:22 PM | #18 |
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Join Date: Oct 2009
Location: Central NJ
Vehicle:2000 OBS '88 BMW K75S |
When my knock sensor went it pretty much gut-punched the car. Could re-set it, but it would always set the code again after a day or two---you'd feel the car lose power the the exact moment the light came on. Given how much better the car felt with the new sensor, it must have been going for a while before it was bad enough to set the code.
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10-26-2010, 03:17 PM | #19 | |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
Quote:
the problem seems to have resolved itself, but if it returns, i will revive this thread. |
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11-24-2010, 12:57 AM | #20 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
problem came back, so i put premium fuel in and it went away........
anyone got any ideas? |
11-24-2010, 12:58 AM | #21 |
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region:
MWSOC
Location: Licking County, Ohio
Vehicle:2005 2.5RS Wagon Regal Blue Pearl |
If octane affects it, it's knock.
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11-24-2010, 01:00 AM | #22 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
thanks for the quick response.
i thought as much, but maybe the knock sensor is bad? it seems unlikely.... maybe there is carbon buildup raising the compression... |
11-24-2010, 01:02 AM | #23 |
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region:
MWSOC
Location: Licking County, Ohio
Vehicle:2005 2.5RS Wagon Regal Blue Pearl |
A bad knock sensor won't respond to changes in fuel. Octane making it better means it's real knock.
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11-24-2010, 01:49 AM | #24 |
Scooby Newbie
Member#: 177894
Join Date: Apr 2008
Chapter/Region:
SCIC
Location: San Diego
Vehicle:99 2.5 RS silver |
what could be the cause other than the intake, engine, ecu combination?
carbon buildup on heads? bad PCV? any ideas? |
11-24-2010, 01:50 AM | #25 |
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region:
MWSOC
Location: Licking County, Ohio
Vehicle:2005 2.5RS Wagon Regal Blue Pearl |
Oil recirc
carbon buildup changing AFR changing compression |
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