C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

<<<<I NEED HELP>>>>>>

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Old Mar 4, 2004 | 01:41 PM
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Default <<<<I NEED HELP>>>>>>

well i fixed the hising in the motor,,, ,,, a vacuum leak at the throttle body,,,,, how did I find this out,,, I replaced all the gaskets to it this morning,,, all of them.....
BUT,,, when I got it all back together , I started it,,,, IT IDLES AT 2200 RPMS,,,, IS it the IAC,, I replaced that gasket too,,,
What do I do,, How do I fix it... :smash:
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Old Mar 4, 2004 | 01:53 PM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

did you plug the IAC back in?
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Old Mar 4, 2004 | 01:54 PM
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Default Re: <<<<I NEED HELP>>>>>> (bogus)

yes, i did plug it back in :confused:
Any clues,,, what would do this
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Old Mar 4, 2004 | 02:19 PM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

Isn't there a procedure on how to reset the AIC in the tech tips section?

I though I read when changing the TB or cleaning out the plenum or TB that afterward you had to run through a little procedure to reset the AIC. hmmm

I'll check

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Old Mar 4, 2004 | 02:25 PM
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Default Re: <<<<I NEED HELP>>>>>> (TheStef)

Isn't there a procedure on how to reset the AIC in the tech tips section?

I though I read when changing the TB or cleaning out the plenum or TB that afterward you had to run through a little procedure to reset the AIC. hmmm

I'll check
:iagree:
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Old Mar 4, 2004 | 02:25 PM
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Default Re: <<<<I NEED HELP>>>>>> (VictorRussell'92)

where the heck is the tech sections :confused:
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Old Mar 4, 2004 | 02:27 PM
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Default Re: <<<<I NEED HELP>>>>>> (TheStef)

A quote from the tech tips section when cleaning the TB, this might not be it but it couldn't hurt to do it.

This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on (car off) and measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.
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Old Mar 4, 2004 | 02:31 PM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

Is something blocking the throttle lever from closing fully? Maybe a misrouted cable is preventing the throttle from closing. Is the throttle lever against the minimum idle screw? Other than one of those, it sounds like another vacuum leak. You might have split the IAC gasket if you overtightened it. Did you retract the IAC pintle as instructed? Have you re-calibrated the IAC? I'm clutching at straws here, trying to help.

RACE ON!!!

PS. In the middle of typing this response, my ISP disconnected me. Sorry to take so long.
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Old Mar 4, 2004 | 02:36 PM
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Default Re: <<<<I NEED HELP>>>>>> (CFI-EFI)

Did you retract the IAC pintle as instructed? Have you re-calibrated the IAC? I'm clutching at straws here, trying to help.

RACE ON!!!
.
No I havent,, any tips on how :D
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Old Mar 4, 2004 | 02:37 PM
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Default Re: <<<<I NEED HELP>>>>>> (TheStef)

A quote from the tech tips section when cleaning the TB, this might not be it but it couldn't hurt to do it.

This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on (car off) and measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.
My TPS is non adjustable
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Old Mar 4, 2004 | 02:41 PM
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Default Re: <<<<I NEED HELP>>>>>> (CFI-EFI)

I dont think I have another vacuum leak,, why,,, when i started the car, I put my hand in front of the TB and I sucked my hand pretty damn hard,,, to the point of holy shiat :eek:
i am going to go pull it back off :mad and see what the hell,,,, can someone post how to reset the IAC please
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Old Mar 4, 2004 | 03:05 PM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

I hope I'm not too late. If you can't detect any vacuum leaks, I wouldn't pull the TB back off. To reset the pintle of the IAC, you push in it until it only sticks out 1 1/8th" from the body. Your ( www.helminc.com) service manual shows this. Even IF adjustable, your TPS would not affect idle speed. To calibrate the IAC, as your service manual spells out, drive the warmed up car at speeds approaching 35-40 mph. That's IT. Take it for a drive and see what happens.

I have to leave for 3 hours. I'll check on you then. Good luck, and...

RACE ON!!!
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Old Mar 4, 2004 | 03:37 PM
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Default Re: <<<<I NEED HELP>>>>>> (CFI-EFI)

alright I fixed it,,,,, I went out and reset the IAC,,,, put the paperclip in a&B ports, waited 30 secs,,, unplugged the IAC,,,, started the car let it run at about 450 to 500 RPMs in drive,,,, shut her down plugged the IAC back in and bang she is perfect once again :thumbs:
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Old Mar 4, 2004 | 03:40 PM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

GREAT!!!!!!!!!!

:cheers: :cheers: :cheers:
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Old Mar 4, 2004 | 04:03 PM
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Default Re: <<<<I NEED HELP>>>>>> (bogus)

I was right!! WHOO HOO!!

If I only knew were the A and B terminals were? hahaha
I don't even know what they look like

I guess spending time in the tech tip section is actualy good. :thumbs:
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Old Mar 4, 2004 | 06:50 PM
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Default Re: <<<<I NEED HELP>>>>>> (TheStef)

I was right!! WHOO HOO!!
You were right??? You had him adjusting his non-adjustable TPS. Not the same as the IAC.
This may be a good point to check and adjust your throttle position sensor. Get two paper clips, straighten out and slide into the end of the TPS sensor connector, A (earth) and B (tps output), keep the wires separate and turn the ignition on (car off) and measure the voltage at the wires and adjust by loosening the torx bolts, if necessary, to 0.54 volts - this is the normal idle setting.
Again, even IF adjustable, the TPS does NOT affect idle speed.
If I only knew were the A and B terminals were? hahaha
I don't even know what they look like
Obviously. Nor the difference in a TPS and an IAC.

1990CORVETTE,
I'm glad you got it. Apparently the IAC calibration procedure has changed in the 6 years in between our cars. Right operation, wrong method.

RACE ON!!!
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Old Mar 4, 2004 | 07:05 PM
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Default Re: <<<<I NEED HELP>>>>>> (CFI-EFI)

go in the tech tips section.... I did pull out the TPS section, but if you keep reading down it explains how to do the AIC, and that thing about the paper clip procedure is all there!

so yes

WHOOO HOO!!
I found it, and I said to go look in the tech tip section.


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Old Mar 4, 2004 | 07:37 PM
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Default Re: <<<<I NEED HELP>>>>>> (TheStef)

I don't deny that the tips section may have the IAC calibration procedure posted. All I know is what YOU posted. You missed the mark, with the TPS.
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Old Mar 5, 2004 | 10:30 AM
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Default Re: <<<<I NEED HELP>>>>>> (CFI-EFI)

Your right, didn't paste the right section from the tech tip post.

But it does say to adjust the AIC, then the TPS, but it also says that later model L98 might be a bit different.

Here's the section if your interested
https://www.corvetteforum.com/techti...D=55&TopicID=2
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Old Mar 6, 2004 | 11:55 AM
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Default Re: <<<<I NEED HELP>>>>>> (1990CORVETTE)

You reset the iac by slight depressing the accelerator and starting the car; let it run for 10 seconds and turn it off. Restart.
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