Stalling Problem-Cant Figure It Out?? Help Please!!
12-06-2007, 09:53 PM
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Stalling Problem-Cant Figure It Out?? Help Please!! Ok guys,
I have researched and cant seem to find out the problem..I recently rebuilt the motor several months back with a crane 218/218 cam...very mild streetable cam, with the usual roller rockers, dual springs, chromemoly pushrods, valvejob, block bored to 355, all the usual bottom end rebuild, full exhaust, 3200 stall and the usual bolt ons...I had it dyno tuned by a friend of mine who does all his own tuning (he has a 697 rear wheel hp 383 camaro that supercharged and runs great) so obviously he knows what he is doing with the tuning...
my issue is that the car was stalling out when i drove it..pretty bad...well when we dyno tuned it we discovered that the previous owner had set the idle at 600 rpms so he upped it to 800 rpms to help out and that worked fine for a while..when you first crank it sometimes it runs great and idles at 800 like it is supposed to and other times it idles at 500 rpms...when your driving it and you let off the gas to apply the brakes it will stall out and you have to crank it back up...sometimes when coming to a stop i have to hold the gas down while holding the brakes so it wont die..and other times it surges at idle when your at a redlight...
I immediately thought i had a vaccuum leak but have went over the motor with a fine tooth comb and cant find anything..it does have an underdrive pulley which i thought may be a contributor..all the emissions and air systems are gone and have been tuned out...does anyone have any ideas..o2 sensors or the pulley..im lost..does the idle need to be moved up to 1000 maybe
thanx in advance for the input
I have researched and cant seem to find out the problem..I recently rebuilt the motor several months back with a crane 218/218 cam...very mild streetable cam, with the usual roller rockers, dual springs, chromemoly pushrods, valvejob, block bored to 355, all the usual bottom end rebuild, full exhaust, 3200 stall and the usual bolt ons...I had it dyno tuned by a friend of mine who does all his own tuning (he has a 697 rear wheel hp 383 camaro that supercharged and runs great) so obviously he knows what he is doing with the tuning...
my issue is that the car was stalling out when i drove it..pretty bad...well when we dyno tuned it we discovered that the previous owner had set the idle at 600 rpms so he upped it to 800 rpms to help out and that worked fine for a while..when you first crank it sometimes it runs great and idles at 800 like it is supposed to and other times it idles at 500 rpms...when your driving it and you let off the gas to apply the brakes it will stall out and you have to crank it back up...sometimes when coming to a stop i have to hold the gas down while holding the brakes so it wont die..and other times it surges at idle when your at a redlight...
I immediately thought i had a vaccuum leak but have went over the motor with a fine tooth comb and cant find anything..it does have an underdrive pulley which i thought may be a contributor..all the emissions and air systems are gone and have been tuned out...does anyone have any ideas..o2 sensors or the pulley..im lost..does the idle need to be moved up to 1000 maybe
thanx in advance for the input
12-06-2007, 10:29 PM
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dern I hadnt really thought about that..you think its needs to be fully replaced or just cleaned..and by the way teh throttle body was fully disassembled when we rebuilt the motor and cleaned..but the IAC hasnt been sprayed with carb cleaner..maybe a bad IAC valve??
12-06-2007, 10:48 PM
#4
Launching!
Definitely IAC valve with your symptoms.
Remove the valve from the throttle body. Do NOT try to move the valve by compressing or uncompressing the spring. Just leave it as is.
Hose the valve off with carb cleaner. Clean out the passage that the valve came out of as well.
Reinstall the valve.
Run this procedure --
Depress accelerator slightly
Start engine, then release accelerator pedal, run engine for 5 seconds
Turn ignition "OFF" for ten seconds
Restart engine and check for proper idle operation
(The above procedure was copied from http://shbox.com/1/4th_gen_tech2.html#iac_reset -- This website has been a tremendous help to myself and others on this forum!!)
Remove the valve from the throttle body. Do NOT try to move the valve by compressing or uncompressing the spring. Just leave it as is.
Hose the valve off with carb cleaner. Clean out the passage that the valve came out of as well.
Reinstall the valve.
Run this procedure --
Depress accelerator slightly
Start engine, then release accelerator pedal, run engine for 5 seconds
Turn ignition "OFF" for ten seconds
Restart engine and check for proper idle operation
(The above procedure was copied from http://shbox.com/1/4th_gen_tech2.html#iac_reset -- This website has been a tremendous help to myself and others on this forum!!)
12-07-2007, 01:34 PM
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Definitely IAC valve with your symptoms.
Remove the valve from the throttle body. Do NOT try to move the valve by compressing or uncompressing the spring. Just leave it as is.
Hose the valve off with carb cleaner. Clean out the passage that the valve came out of as well.
Reinstall the valve.
Run this procedure --
Depress accelerator slightly
Start engine, then release accelerator pedal, run engine for 5 seconds
Turn ignition "OFF" for ten seconds
Restart engine and check for proper idle operation
(The above procedure was copied from http://shbox.com/1/4th_gen_tech2.html#iac_reset -- This website has been a tremendous help to myself and others on this forum!!)
Remove the valve from the throttle body. Do NOT try to move the valve by compressing or uncompressing the spring. Just leave it as is.
Hose the valve off with carb cleaner. Clean out the passage that the valve came out of as well.
Reinstall the valve.
Run this procedure --
Depress accelerator slightly
Start engine, then release accelerator pedal, run engine for 5 seconds
Turn ignition "OFF" for ten seconds
Restart engine and check for proper idle operation
(The above procedure was copied from http://shbox.com/1/4th_gen_tech2.html#iac_reset -- This website has been a tremendous help to myself and others on this forum!!)
thanks, yeah shbox site is a great resource..thanx guys i iwll try this and see if it improves any
