p0507 Idle High, and Idle is searching, any ideas?
02-14-2022, 07:37 AM
#21
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New details. I fired this up the other day, blocked the wheels, set the brake, put the thing in drive.
It idled perfect for almost fourty minutes. Put it in park, same for another ten minutes.
So now I get in the car put in in gear and start idling down the driveway. About 20 feet later the thing
kicks up to about 1200-1500, I let it keep going to see what would happen. Well we got into 2nd goin about 35mph.
Stopped at the end of the driveway and it kicked down but was surging between about 6 and 900 rpm.
Does anyone know if there is some connection between idle and maybe wheel sensors? I'm about ready
to burn this thing to the ground. HEEEELP!
It idled perfect for almost fourty minutes. Put it in park, same for another ten minutes.
So now I get in the car put in in gear and start idling down the driveway. About 20 feet later the thing
kicks up to about 1200-1500, I let it keep going to see what would happen. Well we got into 2nd goin about 35mph.
Stopped at the end of the driveway and it kicked down but was surging between about 6 and 900 rpm.
Does anyone know if there is some connection between idle and maybe wheel sensors? I'm about ready
to burn this thing to the ground. HEEEELP!
02-14-2022, 01:28 PM
#22
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What is the vehicle in question? DBW or cable throttle body?
02-14-2022, 05:42 PM
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My application is a 376/480 LS3 from Chevrolet Performance Parts dropped into a 1994 S10. I hooked it up with a T56 to a 9 inch Ford rear. I needed to use a converter from Dakota Digital for the speedometer to work, analog to digital signal. It is the DBW throttle body with the computer and harness made for the motor. The truck has been running for 4 plus years and every once and a while it throws that stupid code.
02-14-2022, 07:30 PM
#24
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^ More things to consider with the DBW setup you have above. But these older LS1s used a cable TB in the F-body application, so nothing can hold the throttle blade open other than physical cable control/obstruction - beyond that, computer generated air control is limited to only the capabilities of the IAC motor.
02-15-2022, 06:52 AM
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I considered changing over to a cable throttle body, but thought it would be a pain in the butt to do without some tuning software. So I figured I can live with the occasional code. Thanks for the input.
12-07-2022, 05:18 PM
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I will tell you something else to check too that's happened to me in the past if you have a PCV valve on that engine while it is idling pull the PCV valve out and plug your finger on the bottom of the PCV valve if the idle comes back to normal and does right you have a defective PCV valve also check the line off your PCV valve to the vacuum source
10-30-2023, 02:32 PM
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I'm Late to this party but hoping that some of you are still going.
I just did a V6 to V8 swap in a 99 firebird. Put in a 2004 LM4 5.3. I have the high idle issue. I'm sure some of it is due to the fact that I have no vac lines connected yet. My main issue is that the DBW throttle is either intermittent or not functioning at all. Can a high idle cause the TB not to respond to pedal commands?
I just did a V6 to V8 swap in a 99 firebird. Put in a 2004 LM4 5.3. I have the high idle issue. I'm sure some of it is due to the fact that I have no vac lines connected yet. My main issue is that the DBW throttle is either intermittent or not functioning at all. Can a high idle cause the TB not to respond to pedal commands?
