1994 Camaro Z-28 High Idle Problem - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
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post #1 of 10 (permalink) Old Feb 18th, 00, 10:27 AM Thread Starter
 
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I just purchsed a 94 Camaro Z-28 about 5 months ago & this last week, I started having this problem. Sometimes when I start the car (Morning, Day, Or Night) the engine idles anywhere from 1100 - 2000 rpms. Sometimes it comes down to 1000rpms after a few seconds, and sometime it'll stay around 1500-2000 rpms for 15 minutes. I was told that the choke may be sticking. I don't know a whole lot about cars (just enough to get in trouble lol). But I do know some basics.
What do you think the problem may be and should I invest in a service manual or is it something simple?

Oh, I have another problem too (I know I got the shaft when I got this car, but it is so much fun to drive). The check gages light came on the other day, & when I looked down, I noticed the charging meter was reading low (About 12 volts) When I came to a stop the voltage came back up. I think there is a short somewhere, because it is not affected by engine speed (I sat at idle & revved the engine randomly). But when I accelerate or am driving normal, the voltage will sometimes drop back down to +/-12, but also sometimes when I stop, it'll come back up to +/-14v. (It does however happen mainly when the engine is hot. Any help will be appreciated. Thank You!!
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post #2 of 10 (permalink) Old Feb 18th, 00, 10:50 AM
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When you post a message here please include what engine and trans you have. It can have a bearing on what we recommend to you.
Regardless what engine you have Carburetors have not been used on Camaros since the early 80's so I'm shure whatever engine you have, it's fuel injected.

Here's a good guess at what's going on. If the car has over 60,000 miles on it and it's a fiew years old.... The alternator brushes may be wearing out causing the alternator to work at times and at times fail to put out the proper voltage. Also the battery may be getting weak. If the battery voltage is low enough, the computers memory could be erased due to the starter pulling a heavy load on a partially discharged battery. If the computer RAM memory gets zapped due to the low voltage, the computer starts over building a new database and runs the engine at a high idle untill it "learns" what the engine likes when it's cold. There is a permanant map the computer works from that is not affected. The learned data adjusts the permanent map rich or lean a little and sets the idle speeds during warm up.

I'm only saying this is a guess on what it may be. I usually like to cover the basics first. Like the battery and charging system, then look at the hoses, wiring, make shure the plug wires are all plugged in etc. Before getting more involved testing individual components. Observation and reporting to the mechanic exactly what is happening and when, will aid greatly in getting it diagnosed and fixed quickly.
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post #3 of 10 (permalink) Old Feb 18th, 00, 12:34 PM
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WRaynor, You need to take the car to someone you can trust to help you with the problems the car is having. Ask your family members or co-workers if there is a place that they use. Todays cars can be very tough to troubleshoot without a scan tool to ask the computer what is wrong and get the codes. It sounds to me like the CTS( coolant temperature sensor) is showing the computer that it is cold all the time, hence the high idle, but without the scan tool I'd be guessing. It may be a couple of minor things keeping the car from being a real fun and enjoyable car to own and drive.

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the bitterness of poor quality remains, long after the sweetness of the low price is forgotten
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post #4 of 10 (permalink) Old Feb 18th, 00, 02:06 PM
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I'm with Dave ...fix your voltage problem first. Inconsistant voltage will effect the computer and it's sensors. If after that you still have a problem, check basics first i.e. a vacuum leak. Does the check engine light come on? Does check engine light work? should come on breifly with key on. If check engine light comes on...read codes...probably idle air control or mass air sensor.
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post #5 of 10 (permalink) Old Feb 19th, 00, 11:08 AM
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I agree with chev64.
It's hard to judge what the technical ability of the users on this forum. While we try and point you to what we think the problem is...
It would be foolish of us to think everyone we give advice to is able, or has the tools and experience to do the diagnosis and repair, even with our help.
I maintain a fleet of pickups and trucks for our business. But if I get too buisy or the problem is with an auto trans, fuel injection, or ABS. I take a look at it, fix it if it's a simple problem, if not. I send it to the dealer and get it fixed right.

It's a good idea to develop a relationship with a good garage who will take care of your car like a family doctor would your family.
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post #6 of 10 (permalink) Old Feb 19th, 00, 02:14 PM
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Voltage is very important on newer cars (early eighties and up). I had a 85 S10 blazer that was showing the choke light and running funny. Low and behold the alternator was not putting out the right voltage which was affecting the choke (this had a carb) circuits.

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post #7 of 10 (permalink) Old Feb 21st, 00, 06:31 AM
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I'm not sure about the voltage problem, but the irregular idle is probably a sticky Idle Air Control motor. If you know what ytou're doing, this is simple to remove and clean.

Also, before we ream the newby's, as far as I know, the only engine in any '94 Z28 is an LT1! Jim



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post #8 of 10 (permalink) Old Feb 21st, 00, 08:33 PM
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Sorry, WRaynor482
I didn't mean to "ream" you! I didn't notice that you did say you had an 84 Z/28! If you saw my monitor, you'd wonder how I can read anything. It's all squished at the top like the start of Star Wars. Anything at the top of the screen is in a Galaxy, Far Far Away!

[This message has been edited by davidpozzi (edited 02-21-2000).]
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post #9 of 10 (permalink) Old Feb 22nd, 00, 05:43 AM
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David, Your monitor must really be in a galaxy far away, he has a 94 Z-28.

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www.clark.net/pub/chevelle/mcc.htm
the bitterness of poor quality remains, long after the sweetness of the low price is forgotten
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post #10 of 10 (permalink) Old Feb 23rd, 00, 06:30 PM
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Yikes! I think Y2K got ME! Maybe I need some sleep.
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