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94 Legacy- Sputtering, rough idle, bogging on highway

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OK, so I DID search for this first, and found lots of questions but no definite answers.

 

Just picked up a 94 Leg LSi and drove it over 200 miles back home. Put in a MAF that was said to be good when I picked the car up, as the previous owner said it needed a MAF so bad it'd barely run.

 

Here's what's going on currently-

-Roughest idle I've ever seen

-Sputtering at low RPM (below 2000) so badly, I could push it faster between 0 and 5 MPH

-Bogging down on the interstate with occasional spurts of acceleration. Still bogging even at 4500rpm. So bad that on 7% grades, I'd hit the hill at 75mph and get to the top doing 50.

-16MPG on interstate

 

And the kicker- NO activity from the check engine light what-so-ever. Only thing that happened was after I stopped at Advance when getting in town, it sputtered horribly pulling out of the parking lot, and the CEL blinked for the 3 mile trip home. I read that means it was having a condition that could potentially damage the cat converter- correct? Read the trouble codes just for the heck of it, and got nothing.

 

So... where to begin? Suggestions?

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I assume you've checked all the plugs and wires to ensure they are firing. Could be a couple of faulty plugs. Also could be a misfiring coil pack. Or could be a timing belt off by a notch or two. It can still run, but very poorly. Make sure also the air box and the snorkus isn't clogged. If you can't get air, you can't burn fuel.

 

Put a new fuel filter on it. If it is badly clogged, it may cause this kind of problem. I'd also check fuel pressure afterwards if this persists. Could be a faulty fuel pump too, either due to a clogged screen or the pump itself.

 

Is it running rich? Do you smell gas form the engine bay? Black sooty pipes? Perhaps a problem with too much fuel, maybe even a very faulty engine coolant tmeperature sensor. Cheap and easy fix - yank one off a wreck, and swap it. See if there is any difference. Probably not the problem though.

 

I'd check all vacuum lines, make sure they are leaking/disconnected. There is a trick involving the use of a flammable spray (e.g. wd-40 or brake cleaner) that when pulled into a vacuum leak changes the idle I think - I'd check on that though.

 

I'd also check out the idle air control valve, I've heard of this causing similar issues (although to a lesser extent). Not sure how/why though.

 

Thats all I can think of, but I'm hardly knowledgable in these matters. Good luck!

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When was the last time it ran right? Was it something you did? If so trace your steps back. The EJ motors will do this exact same thing if your getting extra air past the MAF. I have three Subs, and none of them will want to stay running the second you start to disconnect the air tube from the intake manifold. They loose all power, and the computer still thinks everything is fine. Sounds like you have a big issue, but Im betting its not.

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For the hell of it, next time you drive it, pull the O2 sensor wire and see what happens.

 

Check your ignition system well, as was stated. Not only your plugs and wires, but the coilpack and even the igniter. Arcing is bad mmmkay?

 

Other than that, possibility of an injector stuck open? Vacuum leak?

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The roughest idle ever seems very much a timing belt off. Fuel probs or fire probs change thru rpms, your problem seems to never leave from idle to 75mph. I would check timing belts before unnecessary parts.:)

I ran an EA82 on two cylinders for months with similar symptoms (I nearly jumped when it was back to normal timing!)

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Any way to check the belt timing without removing the belt covers and looking? Got a timing light, just need to know what to look for. Sorry for the idiot question, but I've never dealt with a mis-timed engine at the belts, just at the distributor level- which of course, this car doesn't even have.

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A bad fuel pump wouldn't account for the horrible gas milage. I'm with those that think its a timing belt, or something in the ignition system. You know the engine is getting fuel, or the mileage wouldn't be so bad. Its either not getting air, or there is nothing there to burn it. The "roughness" is likely because one or more cylinders are not firing when they should, creating an "imbalance".

 

Jordan

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On a whim I checked the current coming through the spark plug wires. Checked with a timing gun on each plug wire about an inch from the coil pack. #1 isn't firing at all at idle, and very sporadically when I rev the engine.

 

So, is this as simple as a dead coil pack, or could it be something else?

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With the car running, pull each spark plug wire and see if the engine dies or idle changes. These engines use a wasted spark ignition system, so if one side of the coil is dead that means two cylinders are going to be dead.

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The engine dies immediately when I pull any of the plug wires, even the one that wasn't pulsing with the timing light.

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Well, I've been feeling pretty sick today and felt like my head was in a vise, so I wasn't thinking too clearly. I forgot to check the basics. All it was was a stinking plug wire!!

 

I don't normally do this, but that warrants a Dancing Banana.

 

:banana:

 

Can't believe the guy sold it at such a loss over that (I paid $800 for the car). Oh well, finders keepers.

 

By the way, here's the car: http://photobucket.com/albums/v504/xtacyturbo/Stuff%20For%20Friends/Legacy/

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Glad it all worked out, Steve....I figured it was something simple.

 

Hey, now don't think I was going to sell it for any more than that 800 bucks, regardless of how she ran! I'd had many miles out of her, but I happily moved on to the wife's 05 Mini Cooper S ragtop (with LSD and DSC!) and I just bought a new (perish the thought) Honda CR-V.....what can I say?

 

My hobby truck will never die...I can go back to wrenching on just that, & not my car anymore....

 

Basically, I wanted to pass on a good working, functional Legacy to someone who could work on it and deal with the usual issues. Sounds like it'll do you right!

 

keep us (and me) updated on your mods, and experiences with the beast!

 

should I say....live long and prosper?

 

keep the sube karma going....

 

adam

:clap:

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Hey, now don't think I was going to sell it for any more than that 800 bucks, regardless of how she ran! I'd had many miles out of her, but I happily moved on to the wife's 05 Mini Cooper S ragtop (with LSD and DSC!) and I just bought a new (perish the thought) Honda CR-V.....what can I say?

 

Adam, you really are an honest man. I consider myself a fair person to do business with- but if the car was running perfect, I personally would have sold it for a lot more. Not its market value, but still quite a bit more than $800. People like you are really what makes the Subaru community such a unique one. Thanks again for the well wishes... and if I'm wanting a CR-V in a dozen years or so... I may just make another trip to Alexandria. ;)

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