my RPMs hang when i come to a stop! help!
12-10-2004, 10:38 PM
#1
my RPMs hang when i come to a stop! help! Why is this? when I come to a stop sometimes my car takes 20 seconds or so to idle down, it will come down, then stop b/w 1700-2000 then drop back down to 800-900. anyone know why? I have a 240/246 .608/.613 LSA 110 cam and stage 3 LS6 heads with full bolt ons. do i need to drill a hole in my throttle body? TIA!
daniel
daniel
12-11-2004, 03:10 AM
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Do you ever get a cruise control effect? If you do its a problem in the running airflow. If not, it's either in the decay or throttle cracker tables....not sure which one.
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12-11-2004, 03:39 PM
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Its the intake air control motor. Its on the tb and adjusts a little blade to allow the right amount of air at idle to hold the desired idle rpm. Yes, I'm pretty sure your problem could be fixed through tuning.
12-11-2004, 04:48 PM
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Mine is doing the exact same thing since the last time I had the PCM reprogrammed (to cure a stalling problem). It will only do this when I start the engine and immediately hit the road. If I let the engine find it's idle (750rpm) after the initial start (say 45-60 sec.), then I know that the problem will not occur.
The way I understand it, when you fire the engine, the PCM need about 1 minute to adjust its parameters.
O/T: Bluestreak98, what kind of exhaust do you have? Headers? Seems that you have minimal clearance at the y-pipe, even for a lowered car. I have almost twice that much even with my SLP headers (I'm stock height).
Nice ride by the way! I love the color and the wheels!
The way I understand it, when you fire the engine, the PCM need about 1 minute to adjust its parameters.
O/T: Bluestreak98, what kind of exhaust do you have? Headers? Seems that you have minimal clearance at the y-pipe, even for a lowered car. I have almost twice that much even with my SLP headers (I'm stock height).
Nice ride by the way! I love the color and the wheels!
12-11-2004, 06:54 PM
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Is the hole in your TB drilled at all? If so, that is what causes it. I had a ported TB with stock cam and the blade was drilled... I would idle at like 2000 or more. I got a stock TB blade and everything was normal.
Normally this is cause by a drilled TB blade, or a leak in the intake... IE lid not sealing well, fernco bellow not sealing well enough... Things like taht
Normally this is cause by a drilled TB blade, or a leak in the intake... IE lid not sealing well, fernco bellow not sealing well enough... Things like taht
12-11-2004, 07:43 PM
#12
I had that idle problem and it turned out the motor was running way lean. I believe someone had messed with my maft when I had some work done. Got embarrassing because the car would be so loud at stoplights with longtubes and orp and a 1500 idle lol. Richened it up and the idle was fine after that.
12-11-2004, 07:51 PM
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I had the exact same problem!! It was fixed in tuning. I took it back to my tuner and he said he had to adjust the "idle decay". I asked "what" he basically said it's how fast the rpms will come down after the vehicle comes to a stop, or after the the accelerator is depressed. Mine works like a charm now. Comes right down like clockwork. My friend had the same problem and drilled the tb and then had idle issues and start up problems. Hope this helps ....
12-11-2004, 09:47 PM
#14
You should find someone with hptuners to helpl you out and you'll know what's going on. Mine did that before I zeroed out the throttle cracker table. Another possibility is if your throttle body set screw was messed with, your throttle position sensor could be telling the pcm that you're holding the gas down so it won't try to go back to the idle rpm.
12-12-2004, 09:39 AM
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mine did the same thing after i installed a cam. auto cruise control. i mailed my pcm to texas speed & they did a bench program for me based of my mods. that solved the problem. it has something to do with the air decay in the program.
12-12-2004, 04:22 PM
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Yea, I know your pain. I keep messing with my tb hole. I just closed it a little. I would rather have it die every once in a while. The cruise control and high idle drove me nuts!