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Old 11-09-2009, 02:09 AM
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Default Riddle me this

What the **** is a SGT and SGC signal? I'm throwing a 3 or 4 code forget which one it was. Any idea.

While I am at it, what is an ISC valve? That little bastard on the right fender with hoses going to it and a single multi pin connector. Mine has been capped off and unplugged since the rebuild, what is that possibly causing?

Sorry, this is a drunk request post.
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Old 11-09-2009, 02:26 AM
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isc valve opens on idle to allow in for air to keep idle. i think that it only adds additional air to compensate for rich conditions or something and actual air to keep idle comes from throttle body. i had extremely rough idle when i accidentally disconnected mine back with oem ecu on my red '96.

sorry if parts of my post dont make sense. took me good 20 minutes to type it up... stoned out of my mind
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Old 11-09-2009, 02:32 AM
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SGT and SGC signal comes from the CAS. Codes 3 and 4 mean the ECU isn't getting one of those signals. Take that as you may, it may be failing or maybe just a loose connection.

ISC(Idle Speed Control) = Idle air control

No more drunken posting.... unless you are flat out wasted so we can all laugh.
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Old 11-09-2009, 02:48 AM
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Originally Posted by DXO
SGT and SGC signal comes from the CAS. Codes 3 and 4 mean the ECU isn't getting one of those signals. Take that as you may, it may be failing or maybe just a loose connection.

ISC(Idle Speed Control) = Idle air control

No more drunken posting.... unless you are flat out wasted so we can all laugh.
Thx for the info
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Old 11-09-2009, 03:33 AM
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The ISC makes sense. My idle has been a bit low and rough since the rebuild. I broke a nipple off the valve and just said **** it and capped off the nipples on the plenum and left the valve unplugged. Not sure about the CAS issue. Would it run correctly without on of those signals? Wouldn't throwing those codes mean you should have a car that either won't run or runs very badly? I do have a bad case of detonation lately, but I was just thinking thats my higher compression ratio and too much advance on the timing. Maybe its not CAS related. I can't afford a new CAS right now, since they are like $500.
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Old 11-09-2009, 03:34 AM
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Originally Posted by UrbanSoot
isc valve opens on idle to allow in for air to keep idle. i think that it only adds additional air to compensate for rich conditions or something and actual air to keep idle comes from throttle body. i had extremely rough idle when i accidentally disconnected mine back with oem ecu on my red '96.

sorry if parts of my post dont make sense. took me good 20 minutes to type it up... stoned out of my mind
Aww man, stoned post. Maybe I won't die from taking Ambien sleeping pills and some Jager shots. I do feel a bit... funny...
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Old 11-09-2009, 03:52 AM
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Yeah if you capped off the isc valve id imagine thats going to be the source of the idle issue and most likely it also causes the car to "buck" under most low throttle areas when trying to cruise.

From what i understand the CAS is pretty important when it comes to the stock ecu for proper operation.

Last edited by Tw34k; 11-09-2009 at 11:24 PM.
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