84' idle question...
Thread Starter
Instructor
Joined: Jan 2004
Posts: 208
Likes: 1
From: NJ
84' idle question...
Hello all,
What is the normal idle on an 84' automatic? I changed my battery and the idle was higher than usual. After driving it over 30 mph to reset IAC, it now idles at 800 to 900 in park or neutral and 700 to 800 in drive. Does this seem right? I looked throught the service manual, but did not find a number as to what the idle should be. For some reason I remember it idling lower than this last fall when I last drove it before winter storage. Thanks for help in advance!!!
Pete
What is the normal idle on an 84' automatic? I changed my battery and the idle was higher than usual. After driving it over 30 mph to reset IAC, it now idles at 800 to 900 in park or neutral and 700 to 800 in drive. Does this seem right? I looked throught the service manual, but did not find a number as to what the idle should be. For some reason I remember it idling lower than this last fall when I last drove it before winter storage. Thanks for help in advance!!!
Pete
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
YOU don't set the idle. It is burned into the prom. Also, there is no need to reset the IACs after changing the battery. Your idle speeds sound about right. If it is higher than it should be, you may have a vacuum leak somewhere. Are the IAC passages clean? Have the TBs been synchronized since they were last removed? I really don't think you have a problem, unless something is preventing the throttle blades from closing or you have a vacuum leak.
RACE ON!!!
RACE ON!!!
Thread Starter
Instructor
Joined: Jan 2004
Posts: 208
Likes: 1
From: NJ
Thanks CFI-EFI. I knew that idle was controlled by PROM, just wanted to make sure that those numbers seemed about right. Throttle bodies were synchronized several years ago and have not been tampered with since, so that should be fine. I think I may clean the IAC becuase I have no idea if the previous owner did that. I always thought that V8s idled lower than six of four cylinders... Thats why I thought it was high. I assume yours runs at about the same idle? Thanks for your help...
Pete
Pete
Racer
Joined: Sep 2004
Posts: 317
Likes: 1
From: 84 Blue A4 Garrison Ky
Mine idles around 600 but it is too low for me, i keep thinking its going to die. The cap is off idle adj. so i know it has been adj. I'm going to raise mine to 700 when i get done replacing water pump.
Pro
Joined: Dec 2002
Posts: 603
Likes: 0
From: 84 383 XFire Chandler, AZ
You can also adjust your idle by balancing your TBs. The procedure for is at the Crossfire Injection Vault. Here is a link to the site - CFI Tech Section
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Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by DRAKEFAMILY2
Mine idles around 600 but it is too low for me, i keep thinking its going to die. The cap is off idle adj. so i know it has been adj. I'm going to raise mine to 700 when i get done replacing water pump.
84whitevette,
Your idle speed sounds just fine. *I* have a small idle problem, but I know EXACTLY why. I'll fix it some day, if I ever decide to remove the TBs, again. The IACs usually are the cause of insufficient or an erratic idle. If you have a smooth idle, I don't see a need to mess with them.
RACE ON!!!
Drifting
Joined: May 2003
Posts: 1,647
Likes: 28
From: Woodbridge NJ
I agree, your idle sounds okay. I also had a slight idle issue. I removed the IAC's and found them to be coated with carbon. I cleaned the IAC's and the housing and my idle is between 600 and 700 RPM's.
I strongly agree with CFI-EFI, I wouldn't touch the throttle stop screws, your looking for trouble. I have an article on synchronization of the TB's, if you don't have a complete understanding of what your doing your car will find it's way to a garage!
I strongly agree with CFI-EFI, I wouldn't touch the throttle stop screws, your looking for trouble. I have an article on synchronization of the TB's, if you don't have a complete understanding of what your doing your car will find it's way to a garage!
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
Greetings all,
Don't want to hijack this thread however I have a related question. Just FYI, I'm more of a C3 nut and usually hang out in that area of the forum. However I just recently picked up a 1984 4+3, Z-51 as a driver. Only 74K fairly well maintained miles.
The crossfire injection is new to me and I need to understand why it wants to idle high, approx 1100-1200 RPM. It sometimes gets down to 900, but more often than not when I lug it down in gear to about 8-900 RPM and then push in the clutch, it jumps upto 1100-1200 and stays there, at least for awhile.
What items do I need to check to address this issue?
TIA.
Regards...............George
Don't want to hijack this thread however I have a related question. Just FYI, I'm more of a C3 nut and usually hang out in that area of the forum. However I just recently picked up a 1984 4+3, Z-51 as a driver. Only 74K fairly well maintained miles.
The crossfire injection is new to me and I need to understand why it wants to idle high, approx 1100-1200 RPM. It sometimes gets down to 900, but more often than not when I lug it down in gear to about 8-900 RPM and then push in the clutch, it jumps upto 1100-1200 and stays there, at least for awhile.
What items do I need to check to address this issue?
TIA.
Regards...............George
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by Brimis
if you don't have a complete understanding of what your doing your car will find it's way to a garage!
RACE ON!!!
