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idle problem w/88 spfi wagon


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after the cars sits over night it starts right up and idles fine, drive it 5-6 miles shut it off for 2-3 minutes ,start it back up it will idle way down and some time even stall , but does not do this all the time , recent tune up, cap,rotor, wires,plugs, fuel filter , acell coil still good, no codes flashing , car has 189,000mi , mpg is 25-26 with ac on, any suggestions ? thanks

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Any chance you have moisture in the fuel tank that gets stirred up by moving around? It gets in whenever you have a partially full tank, and the night air cools and contracts and sucks moist air in and it condenses and sinks to the bottom. Then gets stirred up a bit when the car's moving.

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So, I dunno -- either gas tank water remover (alcohol), or a fuel injector cleaning cycle (however one does that) or both? I assume water's coming through it might carry gummy stuff past the filter that would mess up the injector for a while, but maybe evaporates or dries overnight?

 

Remember -- I have NO idea what I'm talking about. I've owned my 1988 Subaru for gong on 4 months now and never owned any vehicle so complicated before in my life. It's all gizmos and gadgets ....

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looked at it very quickly tonight, heard a ticking around the acell coil, all wires good ,ngk plugs, new cap, rotor, ??

 

Ticking?

 

Boy, I don't know even more about this.

 

In electronics, a ticking or buzz or whistle (a really fast 'ticking') is often a capacitor that is just starting to break down. The voltage builds up, and before it reaches its rated capacity, the electrons escape through a low-resistance flaw. Each time it makes an audible pop. Once you get 440 of those per second you've got a concert "A" musical note (grin).

 

Any coil can do that, if there's a little flaw in the wire insulation so instead of going end to end the electricity short-circuits. So can any place that is supposed to be properly insulated.

 

Aside -- if you were talking about digging into the guts of a monitor or TV, I'd be warning you how to avoid killing yourself by discharging the high voltage capacitor (you take a long wooden stick and a piece of chain, attach one end of the chain to a good grounded pipe or wire, then let the other end of the chain drape over all the exposed wires on the (unplugged) monitor til it goes snap-crackle-pop convincingly) -- high-voltage capacitors can hold a killer charge for literally weeks after the thing's been unplugged.

 

It's different with car computers, less than five volts (much less than you can see or feel) of misplaced electrical discharge can screw them up.

 

I guess with new cars that have computers in them you ought to ask good advice (not mine) about protecting the chips, as well as yourself, before messing with the electrical system.

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Jim, the idle air control valve (IAC) is sticking

 

Located on the front of the throttle body..

(the gizmo that the thottle cable connects to)

 

Has a wire and a rubber hose connected to it

 

There is a picture and a cleaning proceedure

in a previous post.........

 

Good luck, hope you find the problem is

as simple as this "shoud be" maintance item

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i remember working on jims car, we replaced the temp sensor for the ecu so we know thats good.

 

the ecu kept pulling maf codes intermittently, as wiggling wires caused inconsistent troubleshooting

 

jim, didnt you clean the aic, or have me clean it? i remember cleaning one there unless it was the one on the sedan. maybe when the motor(in the dl) was still in the blue wagon i cant remember.

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Jim, I found 172 posts on it,

I realize it's tuff finding the ones that tell you

the procedure.

 

The first one has a picture from the FSM that I posted.

Hope this fixes it.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=27893&highlight=idle+control+valve

 

http://www.ultimatesubaru.org/forum/showthread.php?t=32704&highlight=idle+control+valve

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