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#Full tune-up, still a little rough. CEL's cleared. '90 N/A

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 Post subject: Full tune-up, still a little rough. CEL's cleared. '90 N/A
PostPosted: Fri May 20, 2016 2:57 am 
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Joined: Sat Apr 18, 2015 2:15 am
Posts: 3
So I could use some advice... There are ZERO shops in Cleveland that will even touch this thing, and even my mechanic friends are lost. So thanks in advance to anyone who gives this some thought, Also, it's an automatic.

My car has always had a few CELs, but only while warming up... Once up to temp it was fine. Coolant temp sensor and MAF were the codes.

Few weeks ago, it started stuttering HARD and was dumping gas out the exhaust. It was a bad injector. So I replaced it.

I cleared the codes , but then got a bunch more... IACV, MAF, CTS, and Knock sensor.

I pulled the IACV, cleaned it (althought it wasn't bad) and I'm pretty sure I returned the motor to near stock position.

After replacing the IACV it was idling at 3K!!!

Here's where you're all going to get mad at me... I dialed back the throttle stop screw. YEP. OOPS.

I then replaced it to where it was - roughly, and discovered that the idle condition was due to the PCV connector being cracked - bad vacuum leak. Got one from the dealer along with a new PCV valve, and the idle dropped back down.

So at this point, the idle is kind of normal, but still hunting all over the place, and stalling. MAF code.

A fresh from pull-a-part MAF cleared up the wandering idle and really stabilized it actually.

However, at this point, I got a solid CEL for the coolant temp sensor, so I replaced it, and FINALLY, I have NO FAULT CODES

Replaced plugs too with the recommended NGKs - gapped appropriately.

*********************************************************************
Here's the issue. Everything seems clear for the most part. The idle is stabilized, and I get no stumbling on acceleration.

It just runs a little rough. Idle is stable, but just a little spitty? terrible description, I know... but the car used to run soo smooth.

Do I double check the position of the IAC motor?

Do I turn the throttle body stop screw in a few turns? (noting where it is currently)

Do I do either of these while cold or at operating temp?

Maybe I have a failing piston ring in the cylinder that had the bad injector? Maybe it's the autozone injector?

Test compression?

As always, this car starts quicker than any car I've ever owned, just runs kind of rough now.

I'm so damn close, but it's just not satisfactory.

Any thoughts are greatly appreciated. Hopefully I provided enough info.


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 Post subject: Re: Full tune-up, still a little rough. CEL's cleared. '90 N
PostPosted: Tue Jun 21, 2016 6:05 pm 
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Joined: Tue Oct 15, 2002 11:37 am
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Location: Houston, Tx
These engines tend not to run super smooth, so if that is the only issue then I'm not sure what specific suggestion to make.

Does how the engine runs change with engine rpm?

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Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


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 Post subject: Re: Full tune-up, still a little rough. CEL's cleared. '90 N
PostPosted: Wed Jun 22, 2016 1:20 am 
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Joined: Sat Apr 18, 2015 2:15 am
Posts: 3
Legacy777 wrote:
These engines tend not to run super smooth, so if that is the only issue then I'm not sure what specific suggestion to make.

Does how the engine runs change with engine rpm?


I realize my post was a bit long-winded, so thanks for taking the time to read it and respond.

Long story short, I think the original code for the failing injector was caused by a bad MAF.

I put the original injector back in and it's much, much better. (after replacing the MAF)

This is a testament to using OEM parts!

The idle is still a tiny bit rough, but I honestly think it's fine... I may seafoam the intake if I can find a non-offensive place to do it.

-To answer your question however, the after-market injector idled very poorly as though I had a half-dead cylinder. Above 1500 rpms, though, it was seemingly OK. Once I swapped back to the factory injector, the difference was night and day.

It used a lot of gas on the aftermarket injector, but I haven't gotten through a full tank on the original one (after the tune-up) yet. I'll report back though.


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 Post subject: Re: Full tune-up, still a little rough. CEL's cleared. '90 N
PostPosted: Thu Jun 23, 2016 5:35 pm 
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Joined: Tue Oct 15, 2002 11:37 am
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Location: Houston, Tx
Thanks for the follow up and yeah let us know after you get some more mileage on the original injector.

_________________
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


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