Car is tuned, runs great, at idle it dies when all the electronics are on

ttocs

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yeah my tuner said he kinda had to peg the IAC because my throttle screw wasn't right and the pipe to the crankcase between the MAF and TB was essentially blocked off.
Huh? If he had to peg the IAC then there was bigger problem and are we talking about the intake pipe between the maf/tb? Blocked off how?
 

lwarrior1016

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The iac was maxed because the throttle blade wasn’t open enough. His crankcase ventilation system was plumbed wrong. He had a pcv valve where it should be and it closed off that tube.


So I think as far as setting the idle blade screw, you want the iac unplugged, the car hot, and set the screw so the car idle JUST under target rpm. Then let the iac make up the difference. Also, is there any specific reason you’re keeping the pcv system hooked up?
 

Makoto

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The iac was maxed because the throttle blade wasn’t open enough. His crankcase ventilation system was plumbed wrong. He had a pcv valve where it should be and it closed off that tube.


So I think as far as setting the idle blade screw, you want the iac unplugged, the car hot, and set the screw so the car idle JUST under target rpm. Then let the iac make up the difference. Also, is there any specific reason you’re keeping the pcv system hooked up?

all of that is 100% correct. I'm keeping the pcv system hooked up because its cheap and it'll keep the engine bay a little cleaner. I will probably do a catch can at some point.
 

lwarrior1016

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all of that is 100% correct. I'm keeping the pcv system hooked up because its cheap and it'll keep the engine bay a little cleaner. I will probably do a catch can at some point.
Gotcha. I don’t really care for pcv setups on the 4.6 & 5.4, they always seem to pull in oil residue from the cams. I take that crap off, reroute the vacuum lines and put a can vented to atmosphere with both covers running to it.
 

Notthenow

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All good points IMO. Get the plumbing where you want it, and it's technically correct, and retune. It should only affect idle and part throttle transition. My son and I spent hours tuning his LT1 383 with LS ignition and the idle air and part throttle (a/c installed) was very sensitive. Wide open was easy to get compared.
 

Makoto

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All good points IMO. Get the plumbing where you want it, and it's technically correct, and retune. It should only affect idle and part throttle transition. My son and I spent hours tuning his LT1 383 with LS ignition and the idle air and part throttle (a/c installed) was very sensitive. Wide open was easy to get compared.

i did some tinkering today and I think we definitely got it figured out. high idle is here to stay until the tuner brings that IACV down a bit :D

this car is ROWDY, y'all. can't wait till it idles below 1200-1400rpms. its pretty quiet down around 700 or so.
drove it around a bit today, trying to get the clutch pedal just right, and man this sucker is fun to drive.

I think we can consider this case closed.
 

Notthenow

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Good to hear, will be interested to hear how it goes with the retune. It's fun when a build turns out after all the work.
 

ttocs

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I would think with the idle that high your going to need to adjust the throttle stop a little to open up the butterfly a little.
 

lwarrior1016

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I would think with the idle that high your going to need to adjust the throttle stop a little to open up the butterfly a little.
He did that, that’s why it’s high now. He gave it more air through the throttle blade and the iac is letting even more air in on top of that. When the iac duty cycle gets lowered, the idle will come down.
 

SnakeBit!

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I am certainly no expert and can't chime in on much. The only thing I would say is...I don't believe in coincidences. If everything was ok prior to the tune, no dying of any kind, car running fine then the tune and now an issue. Something is amiss within the tune. Have you discussed the issue you are having with the tuner?
 

SnakeBit!

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all of the above I said, unless something else was done to the car at the time as the tune, other than just tuning it. moving the battery to the back, new cables, new this or that at the same time as the tune. process of elimination based on what was done at the time of the tune.
 

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