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Posted

Hello Everyone,

 

I just joined this forum in hopes for some answers for my car. First of all, I drive a 1991 Subaru Legacy L, 2.2 Non-Turbo Sedan. The problem is my cars idle.

 

My idle has been low, for as long as I can remember, since I bought the car. It has almost 180,000 miles, and I'll try to make an list of maintenance and parts that I have replaced.

 

Just routine oil changes every 3,000 miles

Spark plug wires

Ignition coil

Throttle body

Throttle Position Sensor

PCV Valve

And just today I took off the IAC and cleaned it and replaced the gasket.

 

As far as I can remember thats all....

 

I just really need to figure out why my car idles at around 400 rpm in Park, and also in Drive.

 

If anyone could tell me or just give me some advise, I'd apprciate it.

Thanks

Posted

I assume that you have checked for fault codes.

 

According to the manual I have you shall begin with checking the ignition timing.

 

If you have an AC it shall increase the idle RPM with 100 to 200 rpm.

 

And finally they are referring to possible faults in the crankshaft angle sensor circuit.

 

But you may also have an adjustment screw on the throttle body.

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Posted
Is it stalling or idling rough? Maybe it's supposed to idle at that speed.

 

I'm not much help, heh heh.

 

The idle is pretty much steady at 400rpm. Doesnt stall. Spec shows 600-800rpm idle.

Posted
I assume that you have checked for fault codes.

 

According to the manual I have you shall begin with checking the ignition timing.

 

If you have an AC it shall increase the idle RPM with 100 to 200 rpm.

 

And finally they are referring to possible faults in the crankshaft angle sensor circuit.

 

But you may also have an adjustment screw on the throttle body.

 

I really cant check for fault codes because it is pre OBD 2 so all I have to go on is my check enging light...which isnt on lol.

 

havent checked the timing...but will now.

 

Ill have to diag the crankshaft circuit. And yes I do have adjustment screws on the throttle body but the last time I touched those it messed up everything, and didnt help the idle problem.

Posted

had the same problem, but i had to take the car to dealer and they flashed the computer. it worked fine after that... so it might not be mechanical it might be computer work.

 

Hello Everyone,

 

I just joined this forum in hopes for some answers for my car. First of all, I drive a 1991 Subaru Legacy L, 2.2 Non-Turbo Sedan. The problem is my cars idle.

 

My idle has been low, for as long as I can remember, since I bought the car. It has almost 180,000 miles, and I'll try to make an list of maintenance and parts that I have replaced.

 

Just routine oil changes every 3,000 miles

Spark plug wires

Ignition coil

Throttle body

Throttle Position Sensor

PCV Valve

And just today I took off the IAC and cleaned it and replaced the gasket.

 

As far as I can remember thats all....

 

I just really need to figure out why my car idles at around 400 rpm in Park, and also in Drive.

 

If anyone could tell me or just give me some advise, I'd apprciate it.

Thanks

Posted
Actually - you can check the codes!

 

I suggest that you check out the following page: http://legacycentral.org/library/literature/codes.htm

 

That may help you on the way.

 

 

So according to the code chart, connect the two black connectors to get stored codes that arent setting a check engine light.

 

And connect the two green connectors to get active codes.

 

Right?

Posted

Go ahead - you can't break anything doing this, just remember to have the connectors unconnected afterwards.

 

The worst thing that can happen is that you clear the stored codes you have, but that's no big issue. If it's bad it will come back! If it isn't then you can forget it...

 

Just try to read the codes and note them on a paper.

 

I'm not sure that the ECU on a '91 is flashable, it may be in EEPROM on that model, but it really doesn't matter right now.

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