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Rough/Erratic Idle

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Old Oct 18, 2011 | 05:09 PM
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Rough/Erratic Idle

I have a 1984 Camaro Z28. I seem to be having a problem with the engine. The engine starts and will run if you keep pressing the accelerator. But if you let go the engine will stop.

Also I can get the engine to idle sometimes but when it does it has a really rough idle. The RPM gauge will keep going up and down. It idles rather low.

I am wondering if this is a timing issue or not. If anyone can lead me in the right direction on how to fix this problem it would be greatly appreciated

Thanks in advance!
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Old Oct 18, 2011 | 06:48 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

Is it the factory carburetor on it still?
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Old Oct 18, 2011 | 06:56 PM
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Re: Rough/Erratic Idle

I am not to sure. I dont think so haha It is an edlebrock 305 and i think the carb is a 4 barrel. I am not positive though
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Old Oct 18, 2011 | 07:10 PM
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From: VA
Car: 92 RS
Engine: L03 with Holley Sniper EFI, headers
Transmission: T-5, hurst billet shifter
Axle/Gears: 3.08 posi
Re: Rough/Erratic Idle

I had an idle problem with a 92 R/S TBI system, and couldn't get anyone to fix it. No one seems to know these old EFI systems. I went to 3 different mechanics and it still didn't work write. I had to have a smog check and it died in while waiting in the line. I got it started and asked the smog guy to fix it. He did and it runs better than it has in 10 years. If your state has a smog check, have one of those guys look at it.
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Old Oct 18, 2011 | 07:13 PM
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Re: Rough/Erratic Idle

hahaha thats funny. I think it might be a timing issue though. But im not to sure. The engine sounds great when you press on the gas but you have to keep reving it or it will die. I just want to get to the bottom of this and get my baby running. I have had it for less than a month and everything is coming along great on the car but that part ha
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Old Oct 18, 2011 | 07:14 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

I'm sure it's a 4bbl, the question is what manufacture. Are you saying it's an Edelbrock 4bbl or it has an Edelbrock manifold on it? If it's the factory carb, it will have electrical connectors hooked up to it. Aftermarket carbs wont. At any rate, sounds like it's either WAY out of adjustment or needs rebuilt. Could also be a stuck choke.
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Old Oct 18, 2011 | 07:17 PM
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Re: Rough/Erratic Idle

well how do i fix those things. Because i really dont want to rebuild the carb. Im not sure how to do that and it sounds like it could be expensive. So you dont think it is a timing issue?
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Old Oct 18, 2011 | 07:33 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

If it cranks right up I doubt it's a timing issue. Have you given it a tune up with new plugs, wires, distributor cap and rotor? That can make a huge difference.
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Old Oct 18, 2011 | 07:36 PM
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Re: Rough/Erratic Idle

we put in new spark plugs, oild changes, changed oil filters, and a bunch of other things here and there.

I havent changed the distributor cap.

It usually doesnt start upon the first try. Sometimes we have to spray stuff into the air intake and it will start right up.
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Old Oct 18, 2011 | 07:42 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

you mean starting fluid? if that's the case it could be timing. It's easy enough to check, but you need a timing light. I think factory timing is set at 4 degrees BTC, but you can verify that off the emissions sticker under the hood. Set the timing correct so you know that's eliminated from the equation, then address the issues you still have.
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Old Oct 18, 2011 | 07:47 PM
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Re: Rough/Erratic Idle

I will take a look into it. I am not to sure what you are talking about but i think i have a general idea. Thanks for helping. Any other ideas you think that could help too? I am new to cars and i got this car from a guy at my shop for real cheap. I though it would be a great learning experience and a good car to start of with. I am just going to need help here and there. haha
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Old Oct 18, 2011 | 07:57 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

that's what this site is all about. go by your local auto parts store and pick up a timing light. You should be able to find someone around who can actually show you, or maybe a car club or even a place like Autozone. I can walk you through it, but it's better if you are seeing it first hand.
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Old Oct 18, 2011 | 07:59 PM
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Re: Rough/Erratic Idle

Well i appreciate all the help i have gotten. I never expected this much. So i thank you very much.

I will see if i can get one of the guys at my shop to help out.

If you want i can show you some pics of the car and what i have done with it so far
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Old Oct 18, 2011 | 08:01 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

absolutely, post 'em!
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Old Oct 18, 2011 | 08:12 PM
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Re: Rough/Erratic Idle

Alright well heres alot of pictures. I wanted to take pictures through out the entire restoration process

Ill post these while i wait for the rest to upload

Here are some pictures:


Before the car was cleaned


Before new airfilter









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Old Oct 18, 2011 | 08:13 PM
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Re: Rough/Erratic Idle













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Old Oct 18, 2011 | 08:16 PM
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Re: Rough/Erratic Idle


Before the side panels were cleaned


After the side panels were cleaned
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Old Oct 18, 2011 | 08:25 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

Looks good! keep after it!
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Old Oct 18, 2011 | 08:27 PM
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Re: Rough/Erratic Idle

will do. Do you know where i can get a complete set of seals for the car? i cant really find them as a complete set everywhere (weatherstripping)
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Old Oct 18, 2011 | 08:32 PM
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

Try Classic Industries, Year One, Steele Rubber Products or A&M Softseal, all are good sources.
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Old Oct 19, 2011 | 03:13 PM
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Re: Rough/Erratic Idle

well i figured some stuff out. I have a edlebrock intake manifold and carb. and i am almost positive the engine is actually a 350 not a 305
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Old Oct 19, 2011 | 05:55 PM
  #22  
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From: Memphis, TN
Car: 1992 z28 Purple Haze
Engine: 5.7L Tuned Port Injection
Transmission: 700R4
Axle/Gears: 3.23 both spinning
Re: Rough/Erratic Idle

ok. the engine size really wont matter, there should be a label under the hood with the engine tuning specs. reference this to determine where your timing needs to be set, then set it with a light. we can go from there on any issues you have with rough or erratic idle after that.
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Old Oct 19, 2011 | 06:04 PM
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Re: Rough/Erratic Idle

Alright iwill try that on friday and see if it works out
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Old Oct 21, 2011 | 06:24 PM
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Re: Rough/Erratic Idle

Alright well here is an update. EVERYTHING was out of wack haha

I am a Marine and i am a mechanic so i got the civilian contractor that is in charge of our shop to help me. We fixed all the problems. The distributor, push some gas in the carb because it was dry, and messed with the idle screws. Also the choke was stuck so we fixed that.

I am very happy to say the the camaro is now running like a champ!! It sounds absolutely amazing. Now i can drive around and maybe find some car club around here in North Carolina.

I am have a slight problem with the alternator pulley though. For some reason it keeps twisting the belt. I think it might be because the pulley is a piece of crap. If there is an underlying cause please let me know!

Glad to be an owner of a Camaro. If we werent able to fix the problem today i was probably going to part the car out. I am super happy that i did not have to do that and now i have an awesome camaro!!
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