possible VATS issue.....help
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Instructor
Joined: Sep 2008
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From: Ohio
stalls after 10 minutes? possible VATS issue.....help
93 LT1 - new optispark/coil and computer was rebuild. Car will start and run for 10 minutes, then shut down. Will crank but not start. I lose the signal to the injectors (check with noid light). From time to time the horn will make a quick sound and once the door locked when it shut down. Car will not start until the next day. Thoughts are possible VATS system. I tried a different key (original key used only a few times). Can the VATS cause this condition? Thought the VATS wouldn’t let the car crank as well as disable the injector signal. Is there any way to test VATS without disabling it to be assure this is the issue? Any help would be appreciated
Last edited by fastrad; May 28, 2014 at 11:19 AM.
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From: Melbourne, Victoria, Australia
93 LT1 - new optispark/coil and computer was rebuild. Car will start and run for 10 minutes, then shut down. Will crank but not start. I lose the signal to the injectors (check with noid light). From time to time the horn will make a quick sound and once the door locked when it shut down. Car will not start until the next day. Thoughts are possible VATS system. I tried a different key (original key used only a few times). Can the VATS cause this condition? Thought the VATS wouldn’t let the car crank as well as disable the injector signal. Is there any way to test VATS without disabling it to be assure this is the issue? Any help would be appreciated
Lots of info on how to test and diagnose below
http://www.joestradingpost.com/vats/89_passkey.htm
I know you said no overide but here is one in case you need it
http://www.ecklerscorvette.com/corve...1986-1996.html
Thread Starter
Instructor
Joined: Sep 2008
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From: Ohio
Lots of info on how to test and diagnose below
http://www.joestradingpost.com/vats/89_passkey.htm
I know you said no overide but here is one in case you need it
http://www.ecklerscorvette.com/corve...1986-1996.html
http://www.joestradingpost.com/vats/89_passkey.htm
I know you said no overide but here is one in case you need it
http://www.ecklerscorvette.com/corve...1986-1996.html
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From: Poughkeepsie New York
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From: Melbourne, Victoria, Australia
The 93 may work differently so hopefully someone with a 93 can let you know. This is when a 93 shop manual will come in handy.
check on Ebay, that will have all the diagnostic procedures.
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From: Minneapolis Mn
Thoughts
Are you sure there isn't a 2d alarm system in the car? I've read where more than one person had somewhat similar issues and it turned out to be originating in an addon alarm system.
Other thought is fuel pressure. Is there pressure when the no-start issue is happening?
Other thought is fuel pressure. Is there pressure when the no-start issue is happening?
Thread Starter
Instructor
Joined: Sep 2008
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From: Ohio
oil pressure shows good after car stalls. sets code 16 low voltage. tried putting gas down throttle in case of a fuel issue....same results. If something is heating up and failing it shouldn't take a day of sitting to restart...lost
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Instructor
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From: Ohio
good thought. owner bought new no other changes.
Thread Starter
Instructor
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From: Ohio
sets code 16 - voltage, not sure while it would take until the nest day to start again. car will run for 10 minutes then shut down, crank no start noid light shows no input to injectors. replaced opti with new delco unit, same results
Le Mans Master
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From: WV
Sounds like the ecm to me.. If the injectors stop firing and it's not vats, wouldn't it almost have to be computer related.?? Especally if it starts up the next day...There are only 2 things that I know of that can shut off the injectors,then allow them to start working again, one is the vats , the other is a bad ecm..Something in the ecm could be heating up, then stop working......WW
Last edited by WW7; May 28, 2014 at 06:40 PM.
Race Director
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From: Anaheim CA
More importantly, the ECM will not fire the injectors if it doesn't see ignition reference pulses. The ECM uses the reference pulses to synchronize the firing of the injectors to the rotation of the engine. Just having fuel pressure isn't enough to make the engine run.
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From: Anaheim CA
One other thing that can cause the ECM to stop pulsing the injectors is a bad ignition module. That could be a bad connection somewhere in the wiring between the optispark and the ECM, especially a corroded connector pin.
The ignition module has a thermal shutdown circuit in it. If it gets too hot it will stop sending reference pulses to the ECM. It needs to have THERMAL (not dielectric) grease under it. If that grease is not there you can get the "runs OK cold, dies when hot" problem.