IAC position at closed/partial throttle while driving?
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IAC position at closed/partial throttle while driving?
Just curious. I have a 93 LT1, and during part throttle, very light, or during cruise control I have a slight surge/hesitation. I was think the IAC may be the problem as they do go and dirty up over time.. I can do an electrical test of it with my Ohm meter and it is good, but, can I disconnect it during driving to isolate it as a potential issue?
My 93 has a 396, DELTEQ ignition, and I have an extra delteq brain to swap if necessary too. But, I never have an issue every other throttle position or with AC on in gear and idling..
UPDATE: Just scanned car I have code 72 VSS vehicle speed sensor...
My 93 has a 396, DELTEQ ignition, and I have an extra delteq brain to swap if necessary too. But, I never have an issue every other throttle position or with AC on in gear and idling..
UPDATE: Just scanned car I have code 72 VSS vehicle speed sensor...
Last edited by krackenvette; Jun 24, 2015 at 09:26 PM.
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Just curious. I have a 93 LT1, and during part throttle, very light, or during cruise control I have a slight surge/hesitation. I was think the IAC may be the problem as they do go and dirty up over time.. I can do an electrical test of it with my Ohm meter and it is good, but, can I disconnect it during driving to isolate it as a potential issue?
My 93 has a 396, DELTEQ ignition, and I have an extra delteq brain to swap if necessary too. But, I never have an issue every other throttle position or with AC on in gear and idling..
UPDATE: Just scanned car I have code 72 VSS vehicle speed sensor...
My 93 has a 396, DELTEQ ignition, and I have an extra delteq brain to swap if necessary too. But, I never have an issue every other throttle position or with AC on in gear and idling..
UPDATE: Just scanned car I have code 72 VSS vehicle speed sensor...
Data logging while driving would be a much more effective way to determine what is happening.
According the this list, error code 72 for 1993 is "Gear Selector Switch Circuit". I assume that's the 1-4 skip shift circuit.
https://www.corvetteforum.com/forums...post1576116036
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The IAC is used to set the idle speed and to keep the engine from stalling when the throttle is closed (throttle follower mode). You can disconnect it while the engine is running.
Data logging while driving would be a much more effective way to determine what is happening.
According the this list, error code 72 for 1993 is "Gear Selector Switch Circuit". I assume that's the 1-4 skip shift circuit.
https://www.corvetteforum.com/forums...post1576116036
Data logging while driving would be a much more effective way to determine what is happening.
According the this list, error code 72 for 1993 is "Gear Selector Switch Circuit". I assume that's the 1-4 skip shift circuit.
https://www.corvetteforum.com/forums...post1576116036
Burning Brakes
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From: Richmond Hill Ontario
DTC 72 – is for Vehicle Speed Sensor Loss.
Just thinking if this is true then I believe the ECU will only be using Special BLM CELLs # 16, 17 and 18 . These cells are really only used for Idle (TPS 0%), IDLE TPS greater than 0%. so it sounds as if your fuel correction would be lost when driving/ cruising which would cause you driveabiity issues. The datalog would show this if it is indeed happening.
Just thinking if this is true then I believe the ECU will only be using Special BLM CELLs # 16, 17 and 18 . These cells are really only used for Idle (TPS 0%), IDLE TPS greater than 0%. so it sounds as if your fuel correction would be lost when driving/ cruising which would cause you driveabiity issues. The datalog would show this if it is indeed happening.
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DTC 72 – is for Vehicle Speed Sensor Loss.
Just thinking if this is true then I believe the ECU will only be using Special BLM CELLs # 16, 17 and 18 . These cells are really only used for Idle (TPS 0%), IDLE TPS greater than 0%. so it sounds as if your fuel correction would be lost when driving/ cruising which would cause you driveabiity issues. The datalog would show this if it is indeed happening.
Just thinking if this is true then I believe the ECU will only be using Special BLM CELLs # 16, 17 and 18 . These cells are really only used for Idle (TPS 0%), IDLE TPS greater than 0%. so it sounds as if your fuel correction would be lost when driving/ cruising which would cause you driveabiity issues. The datalog would show this if it is indeed happening.
But my FSM states code 72 for the my 93 Corvette is gear selector switch circuit. Confused.
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"TopTechx6" (I believe that's the correct user ID) had a very good '93 procedure I believe posted.
here's one of his comments and there are others related to TV etc. Search should work well.
https://www.corvetteforum.com/forums...-problems.html
Last edited by WVZR-1; Jun 25, 2015 at 07:02 PM.
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The diagnostic page shows exactly how the circuits are wired I believe. There should be little to no confusion. In your other thread it looked like you were trying to make gear selector into something having to do with PRNDL but it doesn't, it's ASR/TC related stuff relying on pressures from the VB switches. You mentioned the trans had just been redone and the ASR/TV adjustment is critical with there being comments made from time to time that '93 was a particularly tough one. If someone thought they were building the typical 4L60/700R there's things that are very easily overlooked inside. Was the transmission an "off the shelf" product or was it YOUR '93 being built using your VB etc?
"TopTech6" (I believe that's the correct user ID) had a very good '93 procedure I believe posted.
"TopTech6" (I believe that's the correct user ID) had a very good '93 procedure I believe posted.
Thanks for clarifying stuff via fsm. Its gear selector cuircut i am looking at I am going to use it along with datalogging. I can read schematics and have the wirez written down and voltages I need to look for. But it does sag disable ABS, If I remember. Not sure how to do that unless i can pull a fuse?
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Not ABS - don't they just want you to turn ASR "off"? TURN OFF/DISABLE I'd think are somewhat synonymous in this particular situation. I don't believe ABS is of any concern.
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If its ASR Can i disable via button on left side of dash?. At a swim meet so I dont have fsm with me.
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Okay, here are two logs. I noticed my problem is during torque converter lock up. Thats when the car surges. I need to move the lock mph away from 45 and below as that is my cruise speed in town, once out of town and over 55 it can lock up all day as far as I am concerned.
Safe recommendations? My cam is a 230/236 555 560 lift 114 LSA so it is kinda lopey.
Safe recommendations? My cam is a 230/236 555 560 lift 114 LSA so it is kinda lopey.
Last edited by krackenvette; Jan 20, 2021 at 08:32 PM.
Safety Car
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What is your stall speed? I presume it is a lock up converter. If high stall move the stall speed up above your cruise speed. Say on at 56 and off at 50.
If low stall move it more to stock. Say 42 on and 38-39 off.
Yes, I can definitely feel mine lock up. Mine is a 3000 Stall Yank. If feels like a shift actually.
If low stall move it more to stock. Say 42 on and 38-39 off.
Yes, I can definitely feel mine lock up. Mine is a 3000 Stall Yank. If feels like a shift actually.
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What is your stall speed? I presume it is a lock up converter. If high stall move the stall speed up above your cruise speed. Say on at 56 and off at 50.
If low stall move it more to stock. Say 42 on and 38-39 off.
Yes, I can definitely feel mine lock up. Mine is a 3000 Stall Yank. If feels like a shift actually.
If low stall move it more to stock. Say 42 on and 38-39 off.
Yes, I can definitely feel mine lock up. Mine is a 3000 Stall Yank. If feels like a shift actually.