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1992 Metro Lsi question; idle
Topic Started: May 14 2011, 01:16 PM (893 Views)
Isaac
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Ok, so I bought my first ever Metro the other day for the gas mileage. I noticed when I was test driving it that the idle is very high (2000 RPM) so I was thinking it was probably just the idle screw. Well that is all the way in so it isn't that. It also has a pretty rough idle at low RPM. When I use my finger to plug the hose from the silencer to the IAC the idle drops a little bit. Does this sound like the IAC is bad or could it be a vacuum leak somewhere else?

Also, the ground wire to the alternator was loose and sparking so I tightened it up thinking/hoping that might be it but that didn't work either. The check engine light goes off and on so I'm thinking it's a valve somewhere stuck open but am not sure. I'm fairly green at the mechanic stuff and would just like a little bit of guidance on what to check first.

Thanks in advance!
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Bad Bent
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Facetious Educated Donkey

Welcome to your new forum, Isaac! :coffee

The Check Engine Light flashes on and off - there may be a fuse in the raised diagnostic slot of the fuse box. With the fuse in, it flashes a code like on-off-on-on-on for 13. The fuses are located above the driver's left knee. Click on http://geometroforum.com/topic/638390/1/?x=50

Simply replace the vacuum hoses. Get 10' of hose the same ID as yours, take a sample in the parts shop. Replace one at a time according to the sticker on your hood.

There are two idle adjustments in the picture. And this is the link to adjusting a TB idle if it's the same as yours; http://geometroforum.com/topic/2625456/1/?x=40
Posted Image Click on thumbnail. You can unscrew the right screw.
It is likely the PO adjusted the idle really high to mask a problem. The CEL will tell what a problem is. If it was bogging down it may be a clogged catalytic converter, bad distributor cap, arcing plug wires, bad ignition timing of clogged fuel pump, badly adjusted Throttle Position Sensor. Changing the vacuum hoses will eliminate one issue.

Generally, I'd change the PCV valve which may be stuck open (vacuum leak = high idle) and clean all the grounds and wire connections with either sand paper, steel wool or my favorite, a Dremel Tool and small wire brush. Grounds like battery-fender, that sparking wire, the ground wires on the intake manifold above the alternator, and the grounds to the distributor, coil and engine.

Do you have tools? We are very Do It Yourself, if you want to muddle through the werk. :-/
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Memphis metro


Welcome to the forum. Check this out, it will tell you how to retrieve your computer codes to point you in the right direction of your engine malfunction. After you find and repair the reason the check engine light is on, I would suggest do or have done by someone a engine compresssion test. Burned valves are common and are a reason for rough idle.

http://geometroforum.com/topic/638390/1/#new

Welcome to the forum.
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Isaac
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Thanks for the help. I am going to work on it today and hopefully get it figured out!
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Isaac
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I read a post on here where a Tech said if you can suck air in through the top port of the IAC when it's not energized then it's stuck open. I can do that on mine so I'm going to start there if I can find a good one at the junkyard. If that doesn't work then I will do the vacuum hoses and check the other grounds. I checked the coolant lines on the Throttle Body and they get hot when the other hoses do so I think coolant flow is fine. I'm hoping it's just a faulty IAC valve.
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