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Old 02-07-2008, 02:09 PM   #1
jermany755
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Default Problem! Can't rev past 2000 rpm. Idles perfect.

***Fixed***
See post #14


Hey this has gotta be quick cause I'm at work.

Basically my car idles fine but starts to bog as soon as I give it any gas. Neutral revving is better but sounds wierd. I can't rev past 2000 rpms in gear which tops me out at about 40 mph in fifth. If I give it more gas the engine just gets really loud and starts stuttering. I started troubleshooting this yesterday and changed my valve cover gaskets and spark plug wires cause of oil in the plug tubes. Plugs looked fine.

My thoughts are it's either timing belt has skipped a couple of teeth, fuel injectors clogged, fuel pump going out, or cat clogged. Or maybe front O2 sensor going out?

Just wanted to get some nasioc wisdom before I randomly started changing parts out. I have a '01 rs with cobb cai and stromung catback and perrin lightweight pulley. Car has been running great for almost a year till yesterday.

Wouldn't the timing being off mess up my idle as well?

Thanks!

-Jeremy

Oh ya... No CEL.
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Last edited by jermany755; 02-09-2008 at 05:08 PM.
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Old 02-07-2008, 02:41 PM   #2
tludwins539
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Start with the fuel filter or MAF sensor(not sure if this applies to your car).
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Old 02-07-2008, 02:43 PM   #3
Mavrik
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maf is most likely the problem. clean it or make sure its plugged in.
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Old 02-07-2008, 03:51 PM   #4
jermany755
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Ya I'll switch my fuel filter. I don't have maf so chances are it's not that. =p
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Old 02-07-2008, 06:19 PM   #5
Storm
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Start with CEL codes. It sounds like the ECU is in "limp" mode. If no CEL, still look at the MAP sensor being plugged, PCV system plugged or possibly corroded coil terminals.

Jay Storm
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Old 02-07-2008, 08:38 PM   #6
SilverSubie2.5
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Quote:
Originally Posted by Storm View Post
Start with CEL codes. It sounds like the ECU is in "limp" mode. If no CEL, still look at the MAP sensor being plugged, PCV system plugged or possibly corroded coil terminals.

Jay Storm
From what I've experienced, limp mode still allows you to get past 2k rpms, just much much slower. That, and it only lasts for a certain period of time (don't know what it is, though) so I don't think he's in limp mode.
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Old 02-07-2008, 09:45 PM   #7
RaceFaceXC
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i had a very clogged up cat (was in a pontiac) and i couldn't get much power out of the car, the engine didnt like to rev much past 2k and did make a unhealthy sounding noise when the gas was mashed. Took it in, they replaced the cat and that was it. worked just like normal after that. had about 200k on it when the problem started. I didnt have a CEL that i can remember but not sure how the O2 sensor setup was on that car.
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Old 02-08-2008, 01:00 AM   #8
subikid
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Most likely not the PCV. Anything messed up on that and your idle would be horrible too. My guess is the cat. Map sensor doesn't logically make sense bc of the 2k rpm limit. You could be right about the teeth of the belt or however you put it. I'm just kinda stumped haha

Good luck!

Kevin
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Old 02-08-2008, 09:39 AM   #9
sailil
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is 2000rpm a hard ceiling? If not, if you stay in first gear and just let it struggle up closer to 4000rpm, does it suddenly come on strong as if nothing had happened?

My 00RS (no MAF < MAP) did that when the front 02 sensor failed (the $130 one). No CELs either unless the knock got bad enough that misfire codes came up. Sounded and felt awful. scary But replacing the front sensor fixed it completely.

I read later that at idle the ECU generally ignores emissions systems, idle < 3800rpm or so listens to sensors all over the car, then above ~3800 goes "open loop" and ignores the emissions systems again, figuring you're not looking to be effecient if you're WOT up there. I never did figure out what the ECU was doing to the engine while it was seeing faulty 02 signals (pulling timing, going rich, going lean, ????)

something to try, anyway.
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Old 02-08-2008, 10:02 AM   #10
Subie Gal
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certainly sounds like a bad 02 sensor or failed cat

these failing items will not necessarily cause a CEL

diagnosis:
get the car to a subaru repair shop of some sort
get the car on the subaru scan tool
have the tech scan the tolerances for the front 02 sensor
if the sensor correction level is above "normal" - there is your answer.



Jamie
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Old 02-08-2008, 10:57 AM   #11
BlazinYellow
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I did tons of troubleshooting because I had the EXACT problem and it turns out my timing belt jumped two teeth in the end. But like everyone said, try the MAF sensor, check your coil packs, etc. I however, started throwing CELs for misfire in all 4 cylinders.

Ryan
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Old 02-09-2008, 01:57 AM   #12
jermany755
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ok thanks for the help everyone. It was busy today at work so I wasn't able to work on it at all. I have tomorrow off though so I'll be heading down there first thing in the morning. I'm going to fab up a ghetto-rig track pipe for testing purposes to see if that's the problem cause I can do it for next to nothing. I pulled the cat pipe yesterday and could here stuff rattling around inside my cat. =/ I was gonna run it around the block with an open manifold but it was stupid loud so I decided not to. Otherwise I'll limp down to Renton Walker's (gag) and get hooked up to the scan tool. Does anyone know how much service centers normally charge for just a diagnostic check? Or if there's a Subaru repair shop in the Renton/Tukwila area besides Walker's?
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Old 02-09-2008, 08:53 AM   #13
Subie Gal
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Diagnostic checks

fee depends on the shop but they typically charge you 1/2 to 1 hour labor
(so... $50-100)


sorry
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Old 02-09-2008, 05:07 PM   #14
jermany755
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2001 2.5 rs
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Hoorah! Found my gremlin. Turned out to be a clogged cat. I cut off my front cat and dumped a pile of dust and a pretty good sized chunk out of my rear one. Figure that was clogging up the works. For now I just clamped a Napa patch pipe in there so I have a pretty savage exhaust leak, but at least it runs. Tomorrow I'm going to hollow out my front cat as well and have it all welded back together. Thanks again for the help everyone. I'm glad I figured this out before I ran out of money. =)

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Old 02-09-2008, 06:01 PM   #15
BlazinYellow
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Glad you got the problem solved, man.
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Old 02-09-2008, 09:46 PM   #16
RaceFaceXC
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yay, my guess was correct! I better go buy a lotto ticket
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