85...new motor, won't idle
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85...new motor, won't idle
I just got done putting a new engine in my 85 and along with the long list of other problems, the car won't idle.
The new engine is a 409 with a burnett made super victor intake setup, factory ignition and factory throttle body.
The car will run fine if it is running at higher than normal speeds (foot on pedal). But if you let off, the car just dies.
Is this due to the fact that I have the factory throttle body (unchanged) on this bigger engine, or is it something like a bad IAC???
The new engine is a 409 with a burnett made super victor intake setup, factory ignition and factory throttle body.
The car will run fine if it is running at higher than normal speeds (foot on pedal). But if you let off, the car just dies.
Is this due to the fact that I have the factory throttle body (unchanged) on this bigger engine, or is it something like a bad IAC???
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Joined: May 2001
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The IAC should support the larger engine. It might be woefully out of adjustment, clogged, or stuck.
What about the tune? It may require a larger IAC opening to make the larger engine idle. You can cheat it by cracking the throttle blades a little bit.
What about the tune? It may require a larger IAC opening to make the larger engine idle. You can cheat it by cracking the throttle blades a little bit.
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Originally Posted by Dominic Sorresso
Are you using stock ECM and calibration? May need to do a Min Air Adjustment.
Yeah, forgot to include that. I had Jesse Azzato make me a new chip to mate with the new motor. What is a Min Air Adjustment???
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Originally Posted by Nathan Plemons
The IAC should support the larger engine. It might be woefully out of adjustment, clogged, or stuck.
What about the tune? It may require a larger IAC opening to make the larger engine idle. You can cheat it by cracking the throttle blades a little bit.
What about the tune? It may require a larger IAC opening to make the larger engine idle. You can cheat it by cracking the throttle blades a little bit.
I didn't get a chance to get a light on it this time. Also have no idea where to begin timing the damn thing.
How do I know if it requires a larger IAC opening??
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Originally Posted by Billdavis83
What is a Min Air Adjustment???
IAC diagnosis from my manual http://members.shaw.ca/agent86/IAC%20Diagnosis.pdf
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From: Database Error Indiana
Hate to say it, but you have too many mods to just follow the min idle air setting procedure. Your car wont idle at 450 RPM(part of procedure). You have to improvise a bit. Ski probably set the idle speed at 850 0r 900 RPM in the chip. Try and just turn the idle screw in to get that speed and then set the TPS to .54 volts. See what happens. If its not to bad drive it a bit. A scan tool would really help you get the IAC counts down to fine tune the idle. 
Le Mans Master
Joined: Sep 2000
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From: Bartlett IL
Min Air adjustment depends on trying to generate as much vacuum at idle as possible. Also,with a more radical cam, you'd like to have the IAC counts very close to 0 so that more of the airflow is coming thru the throttle plate and not bypassed via the IAC opening. Be interesting to see what Jesse set the IAC steps for idle at. I'm not a proponent of remote control tuning. I'd invest in a WB and learning how to tune. Every motor is very diffferent. You'd be surprised how even changing something like a FW requires a re-tune. 
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Cruise-In II Veteran
Originally Posted by Billdavis83
I just got done putting a new engine in my 85 and along with the long list of other problems, the car won't idle.
The new engine is a 409 with a burnett made super victor intake setup, factory ignition and factory throttle body.
The car will run fine if it is running at higher than normal speeds (foot on pedal). But if you let off, the car just dies.
Is this due to the fact that I have the factory throttle body (unchanged) on this bigger engine, or is it something like a bad IAC???
The new engine is a 409 with a burnett made super victor intake setup, factory ignition and factory throttle body.
The car will run fine if it is running at higher than normal speeds (foot on pedal). But if you let off, the car just dies.
Is this due to the fact that I have the factory throttle body (unchanged) on this bigger engine, or is it something like a bad IAC???
Believe me,im not trying to insult you or put you down,Ive read this entire thread and you do not know what the basics are to get a car running right when its fuel injected.Yes we are here to help..and we will do what we can to help.Its a learning process we all went through,but if youre going to drop a 409 into your engine bay and its efi,you better have a scanner,a lap top and alot of basic knowledge of how fuel injection works.
If you dont youre going to ask alot of questions and blindly try to fix your car and not know why it isnt doing what you need it to do.
EFI and/or TPI sint hard at all,just takes a bit of time to learn how it all works together,prom,sensors and all.
A great book I suggest for the learning is:
http://www.corvettebookstore.com/Pro...tails_7206.ncm
Again please dont take this as a personal insult.I had to assume what I did from your post and responses.If someone else is doing the work and need your info from here,they need to learn some more as well.
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I appriciate you're input, but I am going to see this thing through to the end. I have built various other carbureted cars before, but this is my first crack at fuel injection. I admit that I don't know all there is to know about it, and that is the reason that I started this project. I have learned alot so far and plan on learning more.
So in short, I am going to ask alot of blind questions. And as long as people are kind enough to answer them, I'll keep trudging on.
So in short, I am going to ask alot of blind questions. And as long as people are kind enough to answer them, I'll keep trudging on.
Le Mans Master
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From: Bartlett IL