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Annoying idle issue


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I know there are a million idle issue threads. But none of them seemed to fit my idle issue...

 

Here's what goes on.

89 GL. Manual swapped from an auto.

The computer always has codes 33, 34, and 35. It's had them since I have owned the car, and it has always worked fine.

Goes from high idle nicely down to 700 or 800 rpms.

 

But in the last 3 months, it's started not idling down. It'll stick at maybe 1500 RPMs, sometimes just over 1000. It's annoying as hell.

 

When it first started doing this I checked all the vacuum stuff. Even plugged all of the hoses off so it wasn't possible any air was leaking into the intake. Pulled tho IACV off and cleaned it. Nothing is stuck or leaking.

The timing is good, disty is good, rotor is good, cap is good, wires are good, plugs are new. It's nothing there.

 

BUT if I disconnect the computer, and re-connect it, it works perfectly for about a week. Then starts acting up and doesn't stop till I disconnect the computer. It's been three months of this now, so enough data to show it isn't something else, and that was a one time random fix.

 

This points to a computer problem (in my mind), something in the RAM is getting corrupt and screwing up the idle. But everyone says these computers never fail.... Did my computer fail? heh...

What if I just hook the constant 12v up to ignition so it's off when the car is off...?

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Id check the temp sensor. If its out of whack it would cause that. The car thinks its still cold so it keeps the revs up.

 

Hmm, a possibility. I'll check the resistance chart for temp values. And tonight I'll put it in a pot of water with my digital temp probe. See if it matches up.

I have a spare one somewhere. If I can find it, I can compare the two.

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I've got idle issues that came with the car and have yet to be resolved mines the oppisite tho mine idles down . And just thinking out loud here but is it possible that your Intake manifold gasket is leaking? And maybe the high idle diapraphgm is sticking I'm just gunna keep emptying my brain till this gets solved lol

Edited by AKghandi
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I just have a steady rough idle even after replaceing plugs and wires and also running cans of injection cleaner through it, any idea what it might be? Compression check was also good to, what causes these cars to drain the battery if they sit for about two or three weeks without running, it has a new battery in it, a 2000 Outback 2.5. Thanks for any help!

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That's a completely totally different car than I'm talking about here....

Clean your IACV, make the vacuum leaks go away. Make sure it's OEM wires and NGK plugs... Your alarm system is probably draining the battery....

 

I kindly suggest you start a thread in the new gen forum with your specific problems.

 

 

On a related note. My car has been working perfectly for the last 2 days... Hopefully it stays, but I doubt it will.

I don't see a problem switching the constant 12v to the computer to ignition... I might just do that.

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I wouldn't do that. It just seems like it would cause more problems. And I'm not 100% that ignition provides the same amount of power. the computer is ment to have a memory power source so it can store data if you take that away its going to be trying to relearn everything every time you start it I would imagine that would deffinatly kill the ecu. Your problem isn't the computer. Well I mean it might be but not because yours is bad but because it was an auto and is now a mt the ecus are probably different.. I've got a lot of ideas on what might be causing this like me and my dad had a ford focus that would do almost exactly what your describing it turned out to be a pinhole in one of the fuel lines( although I cant remember where exactly it was) basically air was getting into the fuel line and it would idle really hi then stop then randomly stall and so on

 

Sorry about any grammar errors iPods are hard to type on

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i figured my idle issues out. and it might help you as well. my intake boot was torn between the maf and the turbo causing my car to run rich and die id check that if your problem is irregular like mine was. jiggle the intake boot while its running and see what happens lol(assuming yours is FI)

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I already said it's not a vacuum leak. It's a newish boot on there that I know doesn't leak. I've swapped MAFs, etc. I know it's not that. Besides, why would it go away when I reset the computer and did nothing else if it was a vacuum leak.

 

It's not because it's an auto computer in a manual. It used to work fine. So that's not the problem.

 

I don't see why cutting it's power all the time would upset it. It's not like this computer is some fancy bit of high end engineering with super duper adaptive tuning.

It's an ancient 8-bit computer designed in the 80's.

 

I'm glad you found your problem...

 

Anyone have a good theory as to what's going on?

 

PS. My car isn't a ford focus.

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