'94 Idling too fast
Thread Starter
Racer
Joined: May 2005
Posts: 306
Likes: 5
From: New Orleans Louisiana
'94 Idling too fast
Just bought my first Corvette--1994 convertible with a very recently installed (5000 miles) Jasper remanufactured LT1 engine. Runs beautifully except it idles at a constant 1000 RPM. Should I check to see if the IAC and throttle body need cleaning first?
Thanks,
Steve
Thanks,
Steve
Thread Starter
Racer
Joined: May 2005
Posts: 306
Likes: 5
From: New Orleans Louisiana
Thanks guys, I'll be getting a manual very soon.
Case--my wife and I visited Brisbane and Noosa Beach a year ago. Didn't see many Corvettes in Australia. Mainly because I was too busy making sure I didn't run head-on into other vehicles while driving on the wrong side of the car and the wrong side of the road. Can't wait to get back though.
Steve
Case--my wife and I visited Brisbane and Noosa Beach a year ago. Didn't see many Corvettes in Australia. Mainly because I was too busy making sure I didn't run head-on into other vehicles while driving on the wrong side of the car and the wrong side of the road. Can't wait to get back though.
Steve
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Try to set the IAC first (Sometimes it takes more then one try)
Here is the procedure from the tech tip section
A. Depress accelerator pedal slightly.
B. Start engine and release accelerator pedal, run engine for 5 seconds.
C. Turn ignition “OFF” for 10 seconds.
D. Restart engine and check for proper idle operation.
If that doesn't work you can try cleaning it
https://www.corvetteforum.com/techti...D=94&TopicID=2
good luck and remember there is a lot of great info in the tech tips
Here is the procedure from the tech tip section
A. Depress accelerator pedal slightly.
B. Start engine and release accelerator pedal, run engine for 5 seconds.
C. Turn ignition “OFF” for 10 seconds.
D. Restart engine and check for proper idle operation.
If that doesn't work you can try cleaning it
https://www.corvetteforum.com/techti...D=94&TopicID=2
good luck and remember there is a lot of great info in the tech tips
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Originally Posted by NolaVette94
Thanks guys, I'll be getting a manual very soon.
Case--my wife and I visited Brisbane and Noosa Beach a year ago. Didn't see many Corvettes in Australia. Mainly because I was too busy making sure I didn't run head-on into other vehicles while driving on the wrong side of the car and the wrong side of the road. Can't wait to get back though.
Steve
Case--my wife and I visited Brisbane and Noosa Beach a year ago. Didn't see many Corvettes in Australia. Mainly because I was too busy making sure I didn't run head-on into other vehicles while driving on the wrong side of the car and the wrong side of the road. Can't wait to get back though.
Steve
Good stuff mate, you went right past my place then!! i am between brissy and noosa, if you remember seeing Etamogah Pub on the northbound highway between Brisbane and Noosa, i am about 2 miles east of there in Chancellor Park. Corvettes are not very common on the road here, but mine is out there all the time, its the only kind of car ive ever owned!! I had an 87 for 6 years and 4 days, now got a 94. Send me an email if you like sometime,ill send you some pics. BTW, Noosa is about 30 minutes south of Australia's BIGGEST Corvette dealer!!
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by NolaVette94
Just bought my first Corvette--1994 convertible with a very recently installed (5000 miles) Jasper remanufactured LT1 engine. Runs beautifully except it idles at a constant 1000 RPM. Should I check to see if the IAC and throttle body need cleaning first?
Thanks,
Steve
Thanks,
Steve
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
Originally Posted by MikeC4
look inside your TB and make sure that the butterlies are NEARLY closed at idle. If they are open more than a hair, adjust idle set screw to close them.....The IAC should be sufficient to allow enough air into TB during idle....Some times people mess with the idle screws to compensate for a poor idle, without really figuring out what is causing the problem....
to be more accurate, the butterflies of the LTx engines should be completely closed at idle, only allowing air via a small hole (at least on my LT1) and the IAC circuit.
when i chased down a high idle last year, i first checked for vacuum leaks by spraying starter fluid near potential leaks. i installed intake gaskets just before and found a leak caused by my handiwork. after reinstalling the gaskets (this time with sealant around the ports) and confirming that there were no leaks, i still had an idle close to 1000.
after exhausting all options, that's when i decided to adjust the TB screw (it should be capped off if no one has messed with it). that seemed to do the trick.
good luck finding the cause - just be systematic about it.
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Thread Starter
Racer
Joined: May 2005
Posts: 306
Likes: 5
From: New Orleans Louisiana
I cleaned the IAC pintle, which was pretty much caked with carbon, and cleaned the pintle seat and as much of the TB opening and butterflies as I could reach without removing it from the engine (not enough time right now). Set the pintle position using the setting procedure (slight accel. start, release accel. run for 5 seconds, etc). Did that 3 or 4 times and RPMs now at about 850 to 900. Little better but still not where it should be.
I read that the PCV valve should be checked also but I can't seem to find it. I found a tube running from the TB to the right side valve cover and thought that was it but there is no PCV valve at the rocker cover
end. Only open tubing and an elbow fitting. Where can I find it?
Also, Where exactly is the TB screw to adjust the buttlerfies to a closed position if I find that they may be open during idle? Yes--I'm getting a service manual very soon. Sorry to be a pest.
Thanks for any help.
Steve
I read that the PCV valve should be checked also but I can't seem to find it. I found a tube running from the TB to the right side valve cover and thought that was it but there is no PCV valve at the rocker cover
end. Only open tubing and an elbow fitting. Where can I find it?
Also, Where exactly is the TB screw to adjust the buttlerfies to a closed position if I find that they may be open during idle? Yes--I'm getting a service manual very soon. Sorry to be a pest.
Thanks for any help.
Steve
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
you should be able to see the threaded part of the screw on the driver's side of the TB nearby the armature. the armature hits the screw like it hits a doorstop. the "head" part of the screw should be hidden by a cap.
you can remove the cap, or what i did was i took some needle nose pliers and grabbed the threaded part of the screw to turn it.
you can remove the cap, or what i did was i took some needle nose pliers and grabbed the threaded part of the screw to turn it.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Make sure that it really is idling too fast. I thought mine was idling high since the tach shows about 850 at idle. However, when I run Data Master it logs my idle at 650. I guess my tach reads high, which explains why my WOT shifts are around 6K when the LT1 is only rated for about 5700.
Mike
Mike
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Originally Posted by REDC4CORVETTE
The PCV is located center of the plenum on the drivers side.
Make sure youir heater and A/C is not engauged.
Idle will be around 800 to 1000 with the A/C on.
Make sure youir heater and A/C is not engauged.
Idle will be around 800 to 1000 with the A/C on.
