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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #1 (Edited)
Hey guys, I just want to start a thread to get some input, but also keep updated as I troubleshoot for anyone else who comes across these issues.

Car:
1997 Impreza 2.2L

Faults:
1. Misfires on all four cylinders (it's always a different cylinder combination each time I scan for codes)
2. P0106 - Manifold Absolute Pressure/Barometric Pressure Sensor Circuit Range/Performance


What I've found:
1. Spark plugs had a green-ish, oily substance on them (assumed it was a coolant/oil combo)
2. Car burned oil like crazy
3. The car vibrates very rapidly while driving (a hard vibration almost as if I'm driving over a slightly rough surface)
4. Extremely rough idle
5. Soot all over the back of the car which I'm assuming is because it's running rich

Repairs I've made:
1. New head gaskets with cleaned heads
2. New valve stem seals
3. New rear main and camshaft oil seals
4. New valve cover gaskets
5. New timing belt
6. New intake and exhaust manifold gaskets
7. Resealed oil pan
8. New fuel filter
9. New coil pack
10. Spark plug wires replaced in the recent past
11. New spark plugs
12. Exhaust is all new with somewhat new O2 sensors
13. All of the large vacuum hoses are new (not the small ones, but I did check all the connections on the small hoses and replaced one that was broken)
14. Cleaned the Idle Air Control Valve
15. New Mass Air Flow Sensor
16. New MAP sensor and solenoid valve
17. New knock sensor
18. New rod/crank bearings
19. New pistons with rings
20. New gaskets between block halves
21. Cylinders re-honed for new cross hatching
22. New cam and crank seals
23. New neutral safety switch

There may be some other things, but that's what I can remember off the top of my head. I'm going to continue to troubleshoot and update the thread, but please share your input on where I can look next.

Thanks!
 

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Registered
1995 EZ30 Coupe
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799 Posts
Hmmmm, personally I'd drop in new injectors, but I have a bunch extra already. Might be cheaper/easier for you to test them. It definitely sounds like leaking injectors to me. If they're not the issue I'd try swapping in another ECU.

I think the p0106 is referencing the atmosphere pressure sensor on the passenger strut tower. I had a code for it in my 97 LGT when it wasn't connected to the correct source. Can't remember if it was the same exact code number, but my car still drove fine. Double check your vacuum lines against the diagram on the hood either way.

All I got for now, good luck.
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #4
Hmmmm, personally I'd drop in new injectors, but I have a bunch extra already. Might be cheaper/easier for you to test them. It definitely sounds like leaking injectors to me. If they're not the issue I'd try swapping in another ECU.

I think the p0106 is referencing the atmosphere pressure sensor on the passenger strut tower. I had a code for it in my 97 LGT when it wasn't connected to the correct source. Can't remember if it was the same exact code number, but my car still drove fine. Double check your vacuum lines against the diagram on the hood either way.

All I got for now, good luck.
Thanks for the suggestions! Likely I’ll be looking at the injectors next because I’m starting to run out of things to check.

Today I replaced the entire assembly on the passengers side strut tower which included the MAP sensor, solenoid valve and hoses. Still having the same issues.

I have to assume it’s something to do with the injectors. I’ve already checked the resistance of all four injectors and they’re all basically the same, but they could be plugged, or something. Just strange that the check engine light for misfires varies between all four cylinders, it’s not always the same ones each time I clear it, which makes me wonder if the issue would actually be at the injectors, or it it’s something else.

Does anyone have:

1. Other suggestions of what to check
2. Links to information (or your own knowledge) for checking injectors
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #5
Just in case anyone else is following this. I’ve determined the piston ring in cylinder #2 is leaking. The car was burning oil before and I noticed there was a pool of oil in the spark plug area. I hoped it was just one of the seals, or the head gasket when I had it apart before and just threw it back in. It’s still getting oil in the spark plug area and, on the 2.2L, there’s no remaining other way the oil could be getting onto the spark plug.

Of course this requires me removing the engine and it’s freezing outside, so it’s either wait until it gets warmer and make the repairs, or find a short block to prep inside for a quick swap out when it’s warmer.
 

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Banned
2001 Impreza 2.5RS+T 2001 Legacy GT
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1,248 Posts
I don't like the sounds of "somewhat new" O2 sensors. I recommend a compression test and a leak down test to verify that your combustion chambers are sealing. the spark plug tubes have gaskets at the valve cover so oil could be getting in that way. Here is the diagnostic procedure for P0106 straight out of the service manual. 1997Impreza-P0106Diag.pdf
 

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'97 Impreza L
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2,537 Posts
Discussion Starter #7
I don't like the sounds of "somewhat new" O2 sensors. I recommend a compression test and a leak down test to verify that your combustion chambers are sealing. the spark plug tubes have gaskets at the valve cover so oil could be getting in that way. Here is the diagnostic procedure for P0106 straight out of the service manual. 1997Impreza-P0106Diag.pdf
There are no spark plug tubes, or gaskets on the Phase 1 2.2L. I had a puddle of oil laying on the top of the piston in cylinder #2 and it was spraying all over the spark plug causing my misfire. I replaced all the valve stem seals and head gaskets, so the only way oil could be getting there is if there's blow by from the piston rings. I have it all disassembled and gave it a quick look tonight. I didn't notice anything strange with the rings, but it looks like the cross hatching is totally gone which could be my problem. I'm going to give everything a closer look later, but that's what's standing out the most to me right now.
 

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2001 Impreza 2.5RS+T 2001 Legacy GT
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1,248 Posts
There are no spark plug tubes, or gaskets on the Phase 1 2.2L. I had a puddle of oil laying on the top of the piston in cylinder #2 and it was spraying all over the spark plug causing my misfire. I replaced all the valve stem seals and head gaskets, so the only way oil could be getting there is if there's blow by from the piston rings. I have it all disassembled and gave it a quick look tonight. I didn't notice anything strange with the rings, but it looks like the cross hatching is totally gone which could be my problem. I'm going to give everything a closer look later, but that's what's standing out the most to me right now.
a compression and leak down test would have told you what was wrong without tearing the motor apart. sounds like it might be due for a rebuild any way and you're already half way there!
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #9 (Edited)
Welp. I’m lost. I’ve checked and done absolutely everything related to this issue that I can do. Only things left have to be something else electrical which I don’t have the slightest idea of where to start.

New update is the only code I'm getting now is a P1507.

If anyone can give me valuable insight, here’s what’s still happening:

1. There’s no oil on #2 spark plug now like there was before
2. It can’t idle whatsoever
3. Has a high frequency shake when driving (vibrates so fast it’s nearly smooth, but not)
4. Nearly dies going up a hill unless I have it in first gear
5. Dies once I put it in neutral during a drive because it can’t hold an idle

Anyone have any clues of where to go from here aside from the updated check list above?
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #10
So I was getting a P1507 and from my research did the following
  • Replaced the Neutral Safety Switch for the transmission to fix the p1507
Then I was getting a P0122
  • Was told to check the timing, so pulled the timing belt and noticed the tensioner was leaking fluid, so I replaced that
  • Timing is perfect
Car still can't idle properly and has MAJOR throttle delay. I'm lost and taking it to a mechanic so they can help me diagnose what else even remains to check.
 

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www.jackstalk.com
‘98 RS, 911 Cab, CT6 TT, Escalade ESV
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Does the car have a hood scoop? One issue I had with my 98L was the car was stuck in limp mode because water was getting to the ignition control unit that's bolted to the pitch stop mount area. I didn't see that you replaced that in your initial post. I got so fed up chasing issues and replacing all of the same stuff you did that I took it to a mechanic and that's what they figured out by OHMing it out. The older L's weren't designed to have a hood scoop so without a backing plate the unit is directly in line to get soaked with rainwater.

I just looked it up, it's called the POWER TR UNIT and looks something like this
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #12
Does the car have a hood scoop? One issue I had with my 98L was the car was stuck in limp mode because water was getting to the ignition control unit that's bolted to the pitch stop mount area. I didn't see that you replaced that in your initial post. I got so fed up chasing issues and replacing all of the same stuff you did that I took it to a mechanic and that's what they figured out by OHMing it out. The older L's weren't designed to have a hood scoop so without a backing plate the unit is directly in line to get soaked with rainwater.

I just looked it up, it's called the POWER TR UNIT and looks something like this
Yes, mine does have a hood scoop without a backing plate.

Thanks for giving me something else to check out! I’ll look into this tomorrow and update the thread.
 

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Registered
1995 EZ30 Coupe
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799 Posts
How's the Throttle Position Sensor? (Edit: P0122 is TPS low voltage! Definitely check/swap TPS) Did you check the injectors/FPR? Do you have access to another ECU to swap in?

Also, I think it's just a mistake in terminology, but I want to make sure you didn't put the actual MAP sensor on the strut tower. That's an atmospheric pressure sensor (baro sensor or something?). The MAP is Manifold Absolute Pressure and is located on the intake manifold. If those were swapped they'd do some funky stuff.
 

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www.jackstalk.com
‘98 RS, 911 Cab, CT6 TT, Escalade ESV
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5,622 Posts
Yes, mine does have a hood scoop without a backing plate.

Thanks for giving me something else to check out! I’ll look into this tomorrow and update the thread.
i think i remember like whacking it with a screwdriver while the car was running and it would directly affect the idle so i knew the unit was fucked. I think it was like a $17 part and i may have an extra one laying around in my storage somewhere if you need it.
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #15 (Edited)
How's the Throttle Position Sensor? (Edit: P0122 is TPS low voltage! Definitely check/swap TPS) Did you check the injectors/FPR? Do you have access to another ECU to swap in?

Also, I think it's just a mistake in terminology, but I want to make sure you didn't put the actual MAP sensor on the strut tower. That's an atmospheric pressure sensor (baro sensor or something?). The MAP is Manifold Absolute Pressure and is located on the intake manifold. If those were swapped they'd do some funky stuff.

  • I've given the TPS a visual inspection and it looks, actually, relatively new. I looked in a Haynes repair manual to see if it would show me how to ohm it out, but it only gave ohm readings for a 4 pin and mine is a 3 pin connector. I did, however, check to see if the ohm readings were good for when it was wide open throttle compared to closed and the readings seemed to match up properly for that aspect.
  • I cleaned all of the injectors, but that's all I've done. I'm also pretty sure I gave them power from the battery to see if they would operate and I believe they were fine. If there's another way to check them, I'm all ears.
  • The MAP (on the passenger's strut tower, I believe) is a whole new assembly and the MAF on the air intake is also new. Neither of them are mixed up.
  • I don't have any spare parts for this model to swap over
 

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'97 Impreza L
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2,537 Posts
Discussion Starter #16 (Edited)
i think i remember like whacking it with a screwdriver while the car was running and it would directly affect the idle so i knew the unit was fucked. I think it was like a $17 part and i may have an extra one laying around in my storage somewhere if you need it.
Mine idles so roughly that I'm not sure I'll notice a difference if I whack it, but I can try.

It does make me think though, when it rains my car bogs and jerks hardcore.

I just did this check: How to troubleshoot a no spark condition with a test light

All my readings were similar to what this guy is showing:
  • Red wire was lit but seemed to flicker when cranking
  • Blue wire was lit and stayed solid while cranking
  • Igniter ground was lit when I moved the light to battery positive
  • Computer to igniter wires (yellow wires on top) both had pulses when cranking. The light pulsed and my multimeter readings pulsed.
The only thing I didn't do was the amp draw he took at the end because my clamp meter isn't small enough to get on the wire.

Do you remember anything about the ohm readings they checked to see if yours was good? The check I did does seem like it could be bad, but I'd just hate to spend nearly $200 on it and not have it be the problem.

As far as price, I just did a search on a subaru dealer's site and the part (subaru #22438AA044) is discontinued. Auto zone sells it for $250 which is outrageous and Rock Auto has an option for $30 and one for $179, so I'm not sure what the difference is.
 

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Premium Member
'97 Impreza L
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2,537 Posts
Discussion Starter #17
Well... I got fed up and took it to a repair shop. They scoped the cylinders and found out the cross hatching on one of the cylinders wasn’t done properly so I was only running on three cylinders.

397CA196-9E1E-426C-B055-EFEBE40AE3B3.jpeg


Ended up just buying a used long block and tossed it in just to be done with this whole thing. Runs great now.

Lesson learned to check the work others do on my car. Every time I’ve had to have someone else do work to my car, especially body work, it’s typically not done properly.

Thank you to those of you who provided troubleshooting suggestions; I really appreciate it!
 
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