Engine vibratoin

[steelcitysubie]

Sometimes when I pull out from a stop or go up a hill , I get a slight vibration. When it happens, I think it may not have all the power it usaully does. The engine is stock and I have a IAC problem. I also have a code stating that my engine is running lean. It won't idle w/o me giving it gas when the engine is cold (outside temp. below 40). My economy is alittle lower than norm .

[Legacy777]

What code are you getting?

[log1call]

It sounds like a misfire on one cylinder.
Have you had or done a tune-up?
Who told you there was a trouble code saying it was running lean?

[steelcitysubie]

I got the code. I jumped the wire under the dash. I work at a european repair garage and have some info of subies. I get about 4 codes, I'll check them today and post em. All cylinders are hitting strong. I've seen the harmonic balancer cause vibration , ever see one go bad on a subie? The plugs and filters are less then a year old. The wires? I was gonna get rid of the car cause I can get me hands on a honda for free that needs a engine. I love my legacy and decided no way. I'd rather push my subie through town then be caught in a honduche.

[log1call]

If you could get the guys in the workshop to put your car on the scope they could check your plugs and leads real easily.

If you are doing it yourself then I think the first thig is to try and check whether this vibration is an engine related thing, and more specificaly a misfire, or whether it is a driveline vibration.


If you have already driven a four cylinder car with one cylinder not firing then you will probably know what that frequency is like, does this vibration feel like that frequency?
If it's not at that frequency, how would you describe it's speed... Faster than one cylinder firing frequence? Twice as fast,(which is crank revs)? Wheel/axle revs, (stick a flap of duct tape to your tread and go for a drive and you will hear it)?

No, I've never seen a harmonic balancer give out on a subaru, I think it's only about one in sixteen thousand that has trouble though so perhaps I just need to see more. They are reputed to wear/break their crank keys too but I think that's when they have been off and not tightened properly.

There isn't a code for that car saying that the mixture is lean I shouldn't think, not unless it has an aftermarket or much later ecu. The message will say the O2 is not within parameters which could mean too rich or too lean.
Tell us which codes you've got though.

[steelcitysubie]

The codes are as followed,
12-starter switch-starter switch detected in on positon
22-knock sensor-open or short in circuit
23-airflow sensor-improper air flow sensor detected
24-air control valve-open or short in circuit
31-t.p.s.-open or short in circuit
41-fuel mixture lean-ecu detects lean mixture

I have a workshop manual and a manual just for retriving codes and erasing them . Both books say the same. The engine is out a 95 legacy. I had to swap the harness from my old engine to the newer one . I do some of the old sensors for the swap. The car runs pretty good to have a misfire. I think i'm getting a lean mixture code due to the air valve. i have it adjusted so it will idle a little high so I can start it on those 5 degree mornings. I'm going to buy spark plug wires next week . I don't know how old they are and they look cheap. This fillup I got about 27mpg. thats a city driving. My mpg goes up and down.

[log1call]

But it's just the vibration you are worried about?

[steelcitysubie]

I don't know man, I feel like I've been going in circles in this car. But I do like power slides. The old engine had a bad valve and the key way on the crankshaft pulley broke the crank. I can't be the clutch can it? The cars been awesome. I bought it for $200, put a engine in it 3 years ago and been driving it ever since. Have no other money in it besides maintance.

[log1call]

If you want to figure what it is you need to be systematic. Did you take note of the symptoms I was asking about earlier? If we discover if it's at engine speed first it would be a good idea.

Perhaps you could go to a workshop and ask for an opinion as to the general nature of this vibration if you are really unsure where it is coming from and whether it's the cause or the result of something causing power loss. There will be someone there that will check it and give a quote for free surely? Once we know whether it's a missfire or something falling off then we can proceed to find the cause and cure.

Given the list of trouble codes... it could be anything. Have you cleared those codes and then tested for new ones? Are you sure your wiring is done correctly and is in good order still?

[Legacy777]

Clear the codes, drive the car and check the codes again.