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01-16-2013, 11:55 AM | #1 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
Engine cuts out above 5000 RPMs
I have an issue that I have not been able to remedy since I purchased the car. It is a 2002 WRX wagon with 163k on the body. Previous owner did a lot of work to the car, mostly good parts, not so good work. It has a STi ej20k v3 swap and a lower mileage WRX 5spd transmission. The car will not rev past 5500 RPMs, sometimes won't get over 5000. It happens in all gears and in neutral, under boost and not. Car jerks as the revs bounce and won't continue past. No CEL.
Mods- FMIC 850cc injectors walbro 255 vf28 turbo SR intake turbo back exhaust, no cats clutch upgrade amongst others... Since I purchased I have- Swapped fuel pump, fpr, fuel filter, spark plugs, coil packs, MAF, Turbo, down-pipe, injectors. I cleaned the IACV and replaced gasket, compression test was all good, boost leak test was good, tried several tunes with a reputable tuner, had a subaru guy look at it and do/help with some of the swapping of parts. The car seems to hold boost well, AFR looks good, idles well, starts well... It just won't rev! Previous owner is not very helpful, makes suggestions like "ecu?" or "Maybe the timing belt is on wrong?" I was told the car was detuned and the rev limiter was set low. I know, I'm stupid. Don't trust anyone, even if they have a speech impediment and seem like a real nice guy. I have searched on the site and online, I have worked with one of the most well known Subaru tuners in the state, I have had someone that regularly swaps subaru motors, I took it to a local shop... Next option seems to be a leak down test to check the condition of the heads? I just need some more suggestions, before I pull out this motor. Let me know if I can answer any specifics, thanks.
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01-16-2013, 11:58 AM | #2 |
Scooby Newbie
Member#: 207179
Join Date: Mar 2009
Chapter/Region:
MWSOC
Location: Lake County IL.
Vehicle:2015 WRX Limited WRB 6MT |
Hook it up to a Subaru scan tool and check the readings.(fuel,maf) did you tune it after you added those mods?
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01-16-2013, 11:59 AM | #3 |
Scooby Guru
Member#: 51961
Join Date: Jan 2004
Chapter/Region:
RMIC
Location: Broomfield, CO
Vehicle:2005 STi 2012 WRX |
I doubt a leakdown will tell you anything. Compression problems won't cause a fuel cut at a certain RPM, only the ECU or fueling/ignition problems will. Have you checked the various position sensors (crank position, cam position)? A bad position sensor or a bad reading from a position sensor can cause issues like this.
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01-16-2013, 12:01 PM | #4 |
Newbie Moderator
Moderator Member#: 91347
Join Date: Jul 2005
Chapter/Region:
NESIC
Location: Boston, MA
Vehicle:2004 Tacoma Crew Cab 2012 Triumph 1050 |
You've worked with one of the most well known subaru tuners in the state... at diagnosing this issue?
You've had someone that regularly swaps subaru motors... I'm assuming look at it. You took it to a local shop. What was the outcome of each of these? Obviously they didn't fix it, or you wouldn't be posting. Do you know what tune has been done to it? If you were told it was detuned and the rev limiter set low, isn't that your issue right there? Sounds like it's a crap tune. |
01-16-2013, 12:22 PM | #5 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
The car came tuned with a Cobb AP. Was previously done at P n L in Chicago, even had Jorge's name on the map, and I called to confirm that they had a record of my car. The car was tuned by NF performance when I was first trying some things out, and he tried again after the parts swap. Tried the map that was in there and created a new one, no improvements. I don't think the guy that tuned one of the fastest STis in the state does crap tunes? He saw no issues that he could remedy with tuning, said it must be mechanical.
How do I acquire a Subaru scan tool, from the dealer? I remember them saying they changed out either the cam or crank sensor at PnL back in 2010. But ill look into those. Thanks. |
01-16-2013, 10:49 PM | #6 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
Called PnL back and now they do not have a record of changing one of those sensors? I am fairly positive they said that before, I don't know where else i go that idea. They had done a timing belt service, injector change and plugs. Also did a dyne tune, 264hp. The car was able to rev back in 2010 at least. I am going to change those out anyway. Any other ideas?
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01-16-2013, 10:58 PM | #7 |
Scooby Newbie
Member#: 284835
Join Date: Jun 2011
Location: S.D.
Vehicle:2014 Hyundai Equus White Pearl Mica |
It sounds like fuel cut to me. I had that problem a while back when I was road tuning my car. Try Phatbotti Tuning let them know the problem and see if they can help.
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01-17-2013, 11:31 AM | #8 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
I know the afr gauge is not exactley precise but isn't it close? The fuel looks good whether im under boost or not. Is it possible that it is that dramatic of a change to go from a low 11mileage to lean?
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01-17-2013, 11:49 AM | #9 |
Scooby Specialist
Member#: 232458
Join Date: Dec 2009
Chapter/Region:
SWIC
Location: Las Cruces/El Paso
Vehicle:2005 & 2008 STi Cobb 20g & EFR 7670 |
Double check launch control if you have it setup in the tune, if so turn it off. Check crank/cam sensors and gap as mentioned above, and check grounding on the car. Finally if you have to, get a leakdown done because I'm pretty sure that can tell you if you have a bent valve (no?) which can cause this as well. Valve float can be the cause too.
There are a few threads around here about this. It can be a pain to track down if it's not something easy. Could very well be a mechanical issue |
01-17-2013, 02:13 PM | #10 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
Ok, thanks. My tuner suggested the leak down test. Ill ask him about the launch control. Gonna check the sensors thus weekend. Ive checked the grounds, when you said gap are you referring to spark plugs? Those were changed and gapped proper.
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01-17-2013, 02:39 PM | #11 |
Scooby Specialist
Member#: 332887
Join Date: Sep 2012
Chapter/Region:
Tri-State
Location: Orange County, NY
Vehicle:2012 WRX stage 2+ DGM (sedan) |
Why would launch control even be related to this? It should only activate when the clutch is pressed.
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01-17-2013, 03:03 PM | #12 |
Scooby Newbie
Member#: 343299
Join Date: Jan 2013
Chapter/Region:
NESIC
Vehicle:05 Impreza wrx Rally blue |
Check your speedo sensor on the tranny cause that can also cause it to do that. I had a rock fly up and hit that sensor and my speedo worked but I couldn't rev above 5000 rpms. Most of the time with subarus its dumb little stuff like that
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01-17-2013, 03:08 PM | #13 |
Scooby Newbie
Member#: 343299
Join Date: Jan 2013
Chapter/Region:
NESIC
Vehicle:05 Impreza wrx Rally blue |
But my car was doing the same thing and I spent alot of Money tryin to figure it out untill I replaced that speedo sensor. It's around 80 bucks I would check that out
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01-17-2013, 03:08 PM | #14 |
Newbie Moderator
Moderator Member#: 91347
Join Date: Jul 2005
Chapter/Region:
NESIC
Location: Boston, MA
Vehicle:2004 Tacoma Crew Cab 2012 Triumph 1050 |
If everything was working the way it should be, he wouldn't have an issue. Since ~5000 is around where the launch control cut out is at, it may play a roll if the tune is off.
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01-17-2013, 03:33 PM | #15 | |
Scooby Specialist
Member#: 332887
Join Date: Sep 2012
Chapter/Region:
Tri-State
Location: Orange County, NY
Vehicle:2012 WRX stage 2+ DGM (sedan) |
Quote:
OP, you mentioned the previous owner lowered the rev limiter. Are you talking about the engine redline set by the ECU? Also, you said the original owner detuned it. Are you even properly tuned for your current mods? Last edited by Mr Wrex; 01-17-2013 at 03:50 PM. Reason: added link |
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01-17-2013, 04:13 PM | #16 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
I started looking for that speed sensor but got side tracked, ill take another look at it. Would it matter though if i cant rev no matter if the car is moving or not, under boost or not, in gear or not? Or is that sensor based on a calculation that pressumes the speed of the car?
Its hard to trust anything the past owner said, as far as saying the revs were limited. I think i may be assuming that he was saying the ecus rev limiter was lowered. The car had been tuned prior to me getting it. I tried a few minor things to fix it, then took it to get tuned, he got the car to run much bette, mostly by rescaling the injectors to a smaller size than was told were in there, but not able to fix the rev issue. I changed the plugs, did the boost leak test and attempted to tune again. That did not work so i changed the fpr and coil packs, still not fixed. So i located some injectors and a smaller turbo( was a 18g), and athe maf,and tried another tune. Its been tuned to hell, multiple runs, does well all the way up to that 5-5500 point. |
01-17-2013, 04:30 PM | #17 |
Scooby Newbie
Member#: 343299
Join Date: Jan 2013
Chapter/Region:
NESIC
Vehicle:05 Impreza wrx Rally blue |
Yea you should defiantly check that before spending alot more money cause I went though the same thing with my car I spent over 1g trying to figure out what it was and it was that sensor and my car wouldn't rev above 5 at all untill that sensor was replaced
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01-17-2013, 04:48 PM | #18 | |
Newbie Moderator
Moderator Member#: 91347
Join Date: Jul 2005
Chapter/Region:
NESIC
Location: Boston, MA
Vehicle:2004 Tacoma Crew Cab 2012 Triumph 1050 |
Quote:
The OP has had the car tuned. Do you know his car doesn't have LC on it? Because I didn't see him say that. Nor anything about him changing the set point for the LC. So it's entirely possible that it could be causing a problem. Criminy. I was just trying to explain to Boosted92 why the LC could be causing an issue. Could be the tune is not properly registering the clutch being depressed. Who knows. Worth taking a look though. |
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01-17-2013, 05:43 PM | #19 |
Scooby Specialist
Member#: 232458
Join Date: Dec 2009
Chapter/Region:
SWIC
Location: Las Cruces/El Paso
Vehicle:2005 & 2008 STi Cobb 20g & EFR 7670 |
Crank sensor.
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01-17-2013, 06:17 PM | #20 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
boosted92, did your speedometer still work with the bad sensor?
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01-17-2013, 06:47 PM | #21 |
Scooby Newbie
Member#: 343299
Join Date: Jan 2013
Chapter/Region:
NESIC
Vehicle:05 Impreza wrx Rally blue |
Most of the time it did but sometimes it wouldn't work and the way I tested it was I unhooked the positive terminal on the battery and then hooked it back up and start the car and if its your speed sensor then you should be able to fully rev to tack point and after about 1-2 minutes it will go back to only being able to rev to 5000 rpms again. And my car did that so I changed it and like I said before it fixed my car but I have no idea if that's what's wrong with yours just sayin it might be something to look into cause that sensor is cheap compared to a shops labor rates
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01-17-2013, 08:24 PM | #22 |
Scooby Newbie
Member#: 337037
Join Date: Nov 2012
Location: CA
Vehicle:03 wrx black |
Just like loyal93 said rev limiter I set way low. Have it tuned I bet that's what it is.
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01-17-2013, 08:58 PM | #23 |
Scooby Newbie
Member#: 318667
Join Date: Apr 2012
Location: Midwest
Vehicle:2002 WRX Wagon Black |
I looked into the VSS, another $85 guess... This is a tough one. Ill check the start up and rev attempt
If it was actually the rev limiter would it not be limited to a specific RPM? Sometimes it will got to 5500 other times its at like 5100. I would think it would always limit at an exact? I tuned it before I really made any changes. I tuned it after I made some more changes, not fixed, so I took the advice of my tuner and what to try next. Then I returned to see if those changes helped and had him tune again. Its been tuned with the AP that came with it, and its been unmarried and tuned. I don't know how much more tuned I could get?! |
01-17-2013, 09:00 PM | #24 |
Scooby Newbie
Member#: 337037
Join Date: Nov 2012
Location: CA
Vehicle:03 wrx black |
No because mine is set to 6200 to 6500 until I get bigger injectors, tuners or I know my tuner set the rev limiter there so I don't lean my motor out and blow it. But no it won't be set at a specific rpm it will move a little.
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01-17-2013, 09:01 PM | #25 |
Scooby Newbie
Member#: 337037
Join Date: Nov 2012
Location: CA
Vehicle:03 wrx black |
Open source. Have him hook It up and see what he may have set it at or the ap has it set at.
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