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1990 Legacy LS Idle Issues


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#1 blackdynamite

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Posted 04 November 2010 - 09:05 PM

Hello, I have a Legacy Wagon LS. Recently I've had some idle issues.

It has 160,000 miles. It is Not overheating. The plugs have been replaced before, but the wires are original. This was my fathers vehicle and he had it serviced. Looks like one of the wires had a cut in it it and the mechanics just silicon-ed it up, also wrapping it with electrical tape. Shoddy work in my opinion. It sounds like it's skipping on a cylinder. Whenever i rev it up, it revs fine, and i don't feel a skip. So I started to do some investigating. Pulled all plugs, but they look fine and are gapped correctly. Found a temporary wire from my crv, which is pretty much the same thing. I decide to try to isolate where the misfire was coming from. I started pulling wires while it was running. I notice that on cylinder number 2(closest cylinder on right hand side if facing the car from the front....battery side), whenever i pull the spark plug wire AND/OR the fuel injector wire, the car would run better. If i plug it back in, it runs worse, and if i try to pull any of the other 3 cylinders, it runs Even worse. This blows my mind. I pulled the Maf sensor, seems to be very Clean and to be in good working order. Unplugged the TPS and it would idle up and better, but still seeming to skip a little.

I figured i might have gotten bad gas, BUT i figured that if it were bad gas, it would affect the WHOLE fuel injection system. I'm getting new wires, plugs, and fuel filter. Could anyone help? For some reason i feel it's the Ignition Coil, but I could Be wrong.

Thanks again.
BD

Edit: There is no check engine light on BTW. ;]

Edited by blackdynamite, 04 November 2010 - 09:11 PM.


#2 wtdash

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Posted 05 November 2010 - 12:30 PM

Welcome aboard.

Install the new parts and let us know. HIGHLY suggested to use OEM plugs/wires, if you've not already read that on here. Subies are picky that way.

NGK and Magnecor are OK replacements, too, IMHO.

GL,
Td

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#3 Twitch de la Brat

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Posted 05 November 2010 - 12:35 PM

Check out your fuel injectors.
It sounds like that injector conked out, or may just be too dirty to provide proper flow.

First things first, put half a can of seafoam in your gas tank, it acts like fuel injector cleaner, but better.
Then if it still acts up, try pulling the wire on the injector while the car is running.
If it gets better, or doesn't change, your injector needs either a rebuild, a more in depth cleaning or to be replaced.
Pull the injector and then inspect it to see if there is any junk or gunk on the tip or if the spraying aperture is stuck.

If none of this is the case you probably need to have it rebuilt or replaced.
It shouldn't cost more than $20 or so to get an injector rebuilt.

If you need a replacement, good luck getting one.
They're usually $150+ per injector new and finding them in a junkyard is pure chance.
If you do find them, grab'em, as they are highly sought after.

Twitch

#4 blackdynamite

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Posted 05 November 2010 - 01:13 PM

Welcome aboard.

Install the new parts and let us know. HIGHLY suggested to use OEM plugs/wires, if you've not already read that on here. Subies are picky that way.

NGK and Magnecor are OK replacements, too, IMHO.

GL,
Td

P.s. Telluride is an amazing place!



Well, I'll try a normal set for now, to isolate the problem. But, I'll Defiantly keep that in mind from now on. :]

Yes it is! But i miss the city. It's nice here, but you almost have to get stuff shipped in, because it's cheaper. I should start an autoparts place here. They don't like commercialized stuff here...SO it's 2 hours one way to get fast-food, or auto parts... :-\

Thanks for the welcome! :D

Check out your fuel injectors.
It sounds like that injector conked out, or may just be too dirty to provide proper flow.

First things first, put half a can of seafoam in your gas tank, it acts like fuel injector cleaner, but better.
Then if it still acts up, try pulling the wire on the injector while the car is running.
If it gets better, or doesn't change, your injector needs either a rebuild, a more in depth cleaning or to be replaced.
Pull the injector and then inspect it to see if there is any junk or gunk on the tip or if the spraying aperture is stuck.

If none of this is the case you probably need to have it rebuilt or replaced.
It shouldn't cost more than $20 or so to get an injector rebuilt.

If you need a replacement, good luck getting one.
They're usually $150+ per injector new and finding them in a junkyard is pure chance.
If you do find them, grab'em, as they are highly sought after.

Twitch


I immediately put in a stp gas treatment, so I'll see how it goes.

I'm 2 hours one way to the nearest auto zone, checkers, ETC.

I've always done my own work and went to school for automotive. But i don't have all my tools here yet(just moved from Alabama to Colorado a few months ago), so it's a pain... MEH

I've already fixed 3 Subaru's with wiring problems. I've only seen my dads SubAru up to the point i moved here....and a few STI's near the military base in Bama....LOL. SO...

OH, and I'm a Toyota MkIII Supra Specialist....if anyone ever needs anything. I've owned 5, and have one waiting for me in bama. ;]

I will update whenever i get the new parts in, and install. I'll Definitely check out that injector. :]

Thanks again,
BD

#5 blackdynamite

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Posted 07 November 2010 - 06:50 PM

Put in new spark plugs and wires, took the injector out(which is the biggest PITA i've ever come across....) both looked fine and both worked fine. BUT pinched....then lost.... the little O-Ring that goes on the side of the fuel rail and where the the fuel line connects with 2 screws....FUKC....lol


GEtting fuel filter tomorrow and a new O ring....
MEH....

Though when i took at the fuel filter it did have plenty of gas in it and flowed pretty well, though it was a little brown...so needed a change i guess ;]

Fuel pressure seemed to be pretty strong as well.

Checked EVERY ground and re-did em. Tps Sensor seems to be working fine. I still think there is an issue with the ignition coil.....or some type of wiring issue....

#6 blackdynamite

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Posted 07 November 2010 - 10:15 PM

Also, i noticed that the idle screw on top of the TB was screwed way out. And if i remember correctly on Fuel injected vehicles, you're not supposed to mess with that screw. On my supra you're supposed to screw it all the way in and back out 2 complete turns. Does anyone know? :]

#7 bheinen74

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Posted 07 November 2010 - 10:16 PM

timing belt been replaced recently.
sounds like it skipped a few off.
no biggie, its a non interference year of motor.

#8 blackdynamite

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Posted 07 November 2010 - 10:22 PM

actually i have NO idea when it was Changed, Or if it was EVER changed...Does it have an automatic tensioner? a way to adjust?

I presume there is a guide on how to check it.
I'll do a search, because i am new and i like doing research. :banana:
Not fond of the boxers motors, But i am fond of non interference ;]

#9 Olnick

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Posted 07 November 2010 - 10:48 PM

Not fond of the boxers motors . . . .


Stick around. You will be!!! :lol:

#10 blackdynamite

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Posted 07 November 2010 - 10:54 PM

LOL, i love motors in general...But i would have designed this one Way different...LOL

I wish the Alt, Starter, or A/C was the problem...because they're all easy and accessible...But everything else isn't...ROFL :-\

#11 blackdynamite

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Posted 08 November 2010 - 12:04 AM

Also, whenever the car is under a load under 3000 RPM, you feel a loss of power and it skips a little as well.

Gonna check codes tomorrow.

Hope this helps. ;]

#12 Twitch de la Brat

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Posted 08 November 2010 - 12:23 AM

Also, whenever the car is under a load under 3000 RPM, you feel a loss of power and it skips a little as well.

Gonna check codes tomorrow.

Hope this helps. ;]


The code is probably gonna be a knock sensor.
And your car is OBD I so that's gonna be a manual check, no scanner involved.
The CEL flashes you a code in morse.
Not sure what the method is to get those, but a quick search for "CEL* Code Retrieval" should bring up plenty.
And yes, you need the * as the search function kicks out 3 letter words and the * acts as a placeholder.

Now, since you have mentioned the skip under accel, that sounds like a dead injector, as that was the same exact symptom I had.
I can almost guarantee it's a bad injector.
Just find a new set of injectors and install them.
Junkyards usually only charge like $10-15 per injector, so it's not too expensive to try that out.
But a word of warning, make sure you get the injectors for the same engine and transmission, and also the same color if possible, as mine was finicky with injectors from an engine with a different transmission.

Twitch

#13 blackdynamite

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Posted 08 November 2010 - 12:36 AM

I already found out how to check the codes. My supra's are OBD1, but are a little different and are easier check.

http://au.answers.ya...08171501AATx9qX

Now, i was looking at the codes, if an injector was failing, wouldn't it show a code like 14-17? I tested the injectors and they seemed to work fine. One was a little dirty though....nothing crazy....seen worse.

Same with the knock sensor. It looked like it might have a crack in it. But if it was failing, wouldn't it make the check engine light come on? I don't have a check engine light on now, but i wanna see what codes are stored.

The automatic's had a different looking injector than the manual. i do know that already. :] The only bad part is a live in a town of 2500 people, 3 1/2 hours one way to a town that doesn't have a junk yard. :[

#14 bheinen74

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Posted 08 November 2010 - 12:38 AM

if your knock sensor has a crack, it needs replaced, usually i say go with new, cause they all crack around 100k so getting a good used one is a crap shoot.

#15 blackdynamite

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Posted 08 November 2010 - 01:06 AM

I figured i would have to and i will soon, but would it cause the problem that is at hand now? If i went and unplugged the knock sensor or if it was failing, would it show a check engine light and/or make the skip happen? :]

#16 johnceggleston

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Posted 08 November 2010 - 07:05 AM

I figured i would have to and i will soon, but would it cause the problem that is at hand now? If i went and unplugged the knock sensor or if it was failing, would it show a check engine light and/or make the skip happen? :]


several subaru sensors, at least in the 90s , can work poorly before throwing a code and failing completely. such as knock sensors, o2 sensors and maf sensors. i don't know the threshold of what throws a code but each of those sensors, and maybe, probably, others can cause problems without throwing a code.

#17 wtdash

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Posted 08 November 2010 - 09:10 AM

Also, i noticed that the idle screw on top of the TB was screwed way out. And if i remember correctly on Fuel injected vehicles, you're not supposed to mess with that screw. On my supra you're supposed to screw it all the way in and back out 2 complete turns. Does anyone know? :]


Correct...not 'sposed to touch the TB's top screw. They were only on the '90-91 cars, BTW. Sounds like yours has been messed with....should be a post or 2 on here about it. Also, check out the Legacy Central BBS, which is specific to the '89-94 Legacy.

The '90-91 Autos had gray top injectors; the 5-speeds were different. No offense to Twitch, but I think you could use any year from '90-94, but you'll need the fuel rails AND injectors for the '90-91 5-speeds or '92-94 as they are different. (PM me if you need injectors.)

Also, I hope it doesn't sound like we're asking you to 'throw parts @ it', but everything mentioned has been a useful fix/upgrade on others' cars, and helps eliminate existing issues and future problems.

I'd put money on the KS as causing most of your issues...a cracked KS will put the car in 'limp' mode....although @ that point you'd likely get a code. The '95 ('96?) got an upgrade KS w/a white connector, which may be on a used '89-94 that has been fixed....just an option if a used one is avl.


GL,
TD

Edited by wtdash, 08 November 2010 - 09:17 AM.


#18 blackdynamite

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Posted 08 November 2010 - 10:24 AM

Everyone says not to touch the idle screw, But no one talks about the correct location. Mine was flush with the top of the hole it screws into. i could screw it in about 5 complete times. I'm going to adjust it until i get correct settings on my tps. ;]

I would NEVER think you guys are wanting me to Throw parts at it. ;]

I just ask a lot of questions and i like a combination of answers. This is how i solve problems...LOL. I've learned more about a Subaru in two days, than i have in my whole life. All the information you guys have post has been MORE than enough! I am planning on having the vehicle a good while. So, some what of preemptive maintenance is a good thing. ;)


Pm'ed ;]

#19 Fairtax4me

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Posted 08 November 2010 - 12:02 PM

Same with the knock sensor. It looked like it might have a crack in it. But if it was failing, wouldn't it make the check engine light come on?

Hell no! It's OBD1! The damn thing could be on fire and it wouldn't throw a code. :lol:

But in all seriousness, these are EXTREMELY picky about their "precious" knock sensors. If it's cracked you need a new one.

#20 blackdynamite

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Posted 08 November 2010 - 04:43 PM

Ok, so i checked the codes.

11
12
14
15
16
17
23
24
31
49



The TPS code came from when i Unplugged it, Same with the Idle Air.
LOL i got ALL injectors codes...but then soon figured out this was from me unplugging them whilst it was running to isolate the skip. checked all injectors with a 9v battery and all are operating the same, Clicking, etc.
The Airflow meter looks brand new and the code is due to me unplugging it.

But i took the Idle air out today, the Whole aluminum box unit. Noticed the Spring/Coil inside is FUBAR. The one the size of a half dollar...not the little spring that connects to the 2 wire sensor. Gonna need one of those :[
So that explains some of the idle wondering...

And there is Definitely a crack in knock sensor. So gonna get one of those as well.

#21 johnceggleston

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Posted 08 November 2010 - 04:52 PM

so now that you are on the road to fixing this car, leave the neg battery cable off overnight to clear the codes.

address whatever comes back.

#22 blackdynamite

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Posted 08 November 2010 - 06:28 PM

so now that you are on the road to fixing this car, leave the neg battery cable off overnight to clear the codes.

address whatever comes back.


WAY ahead of you bossman ;]

#23 blackdynamite

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Posted 08 November 2010 - 06:29 PM

Gotta get one of these first ;]

http://cgi.ebay.com/...tem=#vi-content

Edited by blackdynamite, 08 November 2010 - 07:12 PM.


#24 Twitch de la Brat

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Posted 08 November 2010 - 10:23 PM

No offense taken WTdash ;)
My engine was just finicky when I put in injectors from a manual when mine was an auto.
Just was a fair warning.

Now, since you have narrowed it down for us, I think the knock sensor and your IAC are the major offenders.
Might want to investigate the MAF as well, but that's only 4 bolts and a big hose clamp.
I would clean it while you have it out, just shoot it with some electronics cleaner and you should be golden.

Twitch

#25 blackdynamite

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Posted 09 November 2010 - 12:49 AM

Yep, I'll check it out and see what i can figure out. I'll update soon!:banana:

Pulled out the maf sensor and looked inside. It was cleanest I've ever seen one before. LOL It looks Super new. Might have been replaced. I dunno ;]




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