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Old 07-07-2020, 06:04 PM   #1
Wooderz94
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Member#: 516501
Join Date: Jul 2020
Vehicle:
2002 wrx wagon
silver

Impreza WRX Just another 02 wrx only reving to 2500rpm

So as the title states the car will only rev to 2500 to 3500 and cuts out like its hitting a boost cut and will pop and bang 2 or 3 times and just fall in rpms like i let off the pedal but once it gets to 2000 rpm it comes back alive and repeats the process. Ive searched the web to no end and havent come up with much. I just bought the car literally 2 days ago. Its an 02 wrx wagon 5spd manual and the only mods done are a cobb downpipe and catback. There is a engine light on for bank 1 sensor 1 and intake air temp sensor. The car also has a misfire once it warms up but hasnt came up with a misfire code.
What i've done so far:
Cleaned MAF
Checked for boost leaks or any vacuum leak
Checked and changed plugs to oem plugs from subaru (were okay looking but i changed them anyways)
Reset the ecu(unhooked battery overnight)
Unplugged MAF and it idled better? but no code for that either.
This is my first subaru and first turbo car so im not too familiar with either.

What i plan on checking by the end of the week:
Compression test
Swap out good known coils and hope for a difference


Any info would be greatly appreciated! Thanks in advance!
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Old 07-07-2020, 07:31 PM   #2
Samurai Jack
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Member#: 21145
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Not in my own time
Vehicle:
2002 Enemy of Aku

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How much do you know about this car and who you bought it from?

I'm wondering if they had this car modded and turned it back to stock before selling it. If so, could be a tuning issue as you can't rise above 3500.

Did you have a pre-inspection done before purchase

One thing you didn't list as cleaning is the IACV. They can get pretty crappy inside and can use a thorough cleaning

Did you clean the whole MAF or just the little wire you see when you first pull it out?
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Old 07-07-2020, 07:46 PM   #3
Wooderz94
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2002 wrx wagon
silver

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The car used to be my buddies car 2 years ago but alot can happen in 2 years. My buddy never had it tuned an only added the exhaust stuff mentioned and previous owner says he never tuned it which i believe because the car is shockingly the same as when he sold it minus the typical quarter panel rust starting and a few odds and ends like filters and what not.

And i took the car to my brothers garage that has a 4 point lift before buying to go over it but i didnt have a compression tester on hand and the car seemed to run strong until a mile before my driveway bringing it home of course.

I cleaned the entire sensor, wire and up inside. I actually read a write up before cleaning.
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Old 07-07-2020, 09:17 PM   #4
AliBenn
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Location: Houston TX
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1998 /2005 STunIcorn
Acadia Green USDM 22b

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What are exact DTC codes are you getting?
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Old 07-08-2020, 08:36 AM   #5
Samurai Jack
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2002 Enemy of Aku

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Being a 2002 ( a key point since 2004 up it does matter ), adding a DP and catback will not really affect much. A tune will just bring out the best in it.

If you haven't already, first thing I would do is clean the IACV. Plenty of videos showing how. Isopropyl Alcohol and/or brake cleaner and lots of Q-tips are your friends here.

You will probably need to purchase a new gasket.

Do that and see if it changes things.
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Old 07-08-2020, 09:07 AM   #6
Wooderz94
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2002 wrx wagon
silver

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Quote:
Originally Posted by Samurai Jack View Post
Being a 2002 ( a key point since 2004 up it does matter ), adding a DP and catback will not really affect much. A tune will just bring out the best in it.

If you haven't already, first thing I would do is clean the IACV. Plenty of videos showing how. Isopropyl Alcohol and/or brake cleaner and lots of Q-tips are your friends here.

You will probably need to purchase a new gasket.

Do that and see if it changes things.
Alright I’ll give that a shot tonight, thank you. You don’t think the bank one sensor one heater circuit malfunction would play a role in this either? Correct me if I’m wrong but isn’t that the wideband?
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Old 07-09-2020, 08:53 AM   #7
Wooderz94
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2002 wrx wagon
silver

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So I did a compression test on the car before I did anything else just to ease my mind basically. I got 140 on #1 135 on #2 145 on #3 and 135 on #4. While the plugs were out I noticed they are super lean looking, Also if I shut the car off and prime the fuel pump a few cycles and start it I can rev it out to redline, but if I try it again without priming pump it falls on its face like stated in first post. But I am now going to clean the IACV due to the unsteady idle (not high or low idle just fluctuates slightly) and do a fuel pressure test.
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Old 07-09-2020, 09:14 AM   #8
Samurai Jack
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2002 Enemy of Aku

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Quote:
Originally Posted by Wooderz94
You don't think the bank one sensor one heater circuit malfunction would play a role in this either?
CELs are funny animals. They only point you in a certain direction but rarely give you the exact issue right off the bat. Always best to start with baby steps, simplest to hardest ( cheapest to expensive ) when looking for the culprit.

Quote:
Originally Posted by Wooderz94
I got 140 on #1 135 on #2 145 on #3 and 135 on #4. While the plugs were out I noticed they are super lean looking, Also if I shut the car off and prime the fuel pump a few cycles and start it I can rev it out to redline,
Those numbers show a decent balance across the cylinders. Plugs are nice and clean and dry so you're not running excessively rich or ultra lean.
- Did you notice any deposits on the plugs? Did they all look the same?

The fuel pump should automatically prime itself when you turn on the key. You should also be waiting for the pump to prime before starting the car. This takes what, a couple of seconds, so it's not a big deal.

I hope you didn't rev to the redline while sitting in your driveway. Not a good idea to rev an engine like that without a load on it.
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Old 07-09-2020, 09:49 AM   #9
Wooderz94
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2002 wrx wagon
silver

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Quote:
Originally Posted by Samurai Jack View Post
CELs are funny animals. They only point you in a certain direction but rarely give you the exact issue right off the bat. Always best to start with baby steps, simplest to hardest ( cheapest to expensive ) when looking for the culprit.



Those numbers show a decent balance across the cylinders. Plugs are nice and clean and dry so you're not running excessively rich or ultra lean.
- Did you notice any deposits on the plugs? Did they all look the same?

The fuel pump should automatically prime itself when you turn on the key. You should also be waiting for the pump to prime before starting the car. This takes what, a couple of seconds, so it's not a big deal.

I hope you didn't rev to the redline while sitting in your driveway. Not a good idea to rev an engine like that without a load on it.

Fuel pump primes as it should but I was cycling it to see if it made any difference after startup. Also the plugs were super clean but very lean looking(had a blue hue to them) also the car was already warmed up when I did the rev test and I didn’t actually hit rev limiter as that wasn’t the intentions. I reved the car up to see if it would rise above 2500rpm and when I seen 6k I let off. But that literally was the first time the car has reved that high so I wasn’t expecting it honestly. So cycling the fuel pump(full cycles till it shut off) then starting made a difference. The car actually seemed to idle better as well for 30 seconds or so then right back to the issues. I ordered the IACV gasket yesterday so I’ll be cleaning that tonight as well.
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Old 07-20-2020, 01:36 PM   #10
Wooderz94
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2002 wrx wagon
silver

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Update
Previous owner told me he did the timing kit including water pump so i checked and it out to be safe and the timing was off a tooth on one cam so i thought awesome thats the problem! So i took it all apart and re timed it and the car runs better and is more responsive but it still cuts out only now it cuts out between 3500-4500rpm... I am going to test the fuel pressure and check for boost leaks again. I installed a new MAF also and the idle seems much better not searching or high. I am about at whits end with this thing as it seems like everything i do makes little or no difference.
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Old 07-21-2020, 12:27 PM   #11
Wooderz94
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2002 wrx wagon
silver

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Fuel pressure is in spec, but I found a hole in the turbo inlet hose which I ordered a new one but I highly doubt that would cause the issue I’m having. Any helpful info would be absolutely awesome.
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