mysterious starting problem
Team Owner
Joined: Jan 2003
Posts: 20,306
Likes: 242
From: Summerland B.C. Canada
The enable signal goes to B6 (24 pin connector) at ECM. I would think that is a whole lot easier to get to, but that does not allow you to test any of the ins and outs of VATS module, if required.
The fact that you have an aftermarket security system added to the car, may make this more of a headache to diagnose.
VATS module is the grey box.
Here is some info on dash removal.
http://members.shaw.ca/agent86/Dash%...%20Removal.pdf
I am interested in the fix that involves reprogramming the ECM. This sounds like less of a haste and eliminates the problem of a repeated VATS failure.
Do you know if this is an option that would work for my car/ECM??? Or does this only work with a "programmable" ECM.
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Do you know if this is an option that would work for my car/ECM??? Or does this only work with a "programmable" ECM.
.
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 21
Likes: 0
WOW that makes it way easier. i was looking all over under the hush panel near the ECM and that was close but impossible to access from that area.
so i am trying to send you photos on here but i cant figure out how to send attachments. regardless the Security system is "UNGO" model #MS9000 it has an FCC # so imagine its remote operated. I didn't check with a tester light but it looks to be dissconected(cut wires)but if i put the key in the ignition the security box makes an audible click about every second.?!
ill test the Vats Decoder Module tonight/ right now.
so i am trying to send you photos on here but i cant figure out how to send attachments. regardless the Security system is "UNGO" model #MS9000 it has an FCC # so imagine its remote operated. I didn't check with a tester light but it looks to be dissconected(cut wires)but if i put the key in the ignition the security box makes an audible click about every second.?!
ill test the Vats Decoder Module tonight/ right now.
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 21
Likes: 0
[QUOTE=AGENT 86;1576891329]The enable signal goes to B6 (24 pin connector) at ECM. I would think that is a whole lot easier to get to, but that does not allow you to test any of the ins and outs of VATS module, if required.
Ok i tested the VATS Decoder Module and at no point did i get a 5v reading with the key in start position. (read 2.8) also it said PPL wire at terminal P. the wire in terminal P is blue not purple and the purple wire is the second from the bottom turminal. i tested both purple and blue and there almost identical in v.
During cranking it droped slightly to 2.3v until it stopped cranking and returnd to 2.8v.
is there more testing needed. ill look at the port where it enters the ECM and test it there for the desired 2 to 3v it needs during crancking.
is a chip burn a cure all for problems even if the VATS decoder is still bad??
Just trying to see what parts i should get the ball rolling on for ordering.
Ok i tested the VATS Decoder Module and at no point did i get a 5v reading with the key in start position. (read 2.8) also it said PPL wire at terminal P. the wire in terminal P is blue not purple and the purple wire is the second from the bottom turminal. i tested both purple and blue and there almost identical in v.
During cranking it droped slightly to 2.3v until it stopped cranking and returnd to 2.8v.
is there more testing needed. ill look at the port where it enters the ECM and test it there for the desired 2 to 3v it needs during crancking.
is a chip burn a cure all for problems even if the VATS decoder is still bad??
Just trying to see what parts i should get the ball rolling on for ordering.
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 21
Likes: 0
so i tested it again and it showed 5v then i turned it over and it started right up. Previous to this i just pulled out the whole unit disconnected it and inspected the connections and blew in the module to clear debrie of dust then puged it back in.
now it starts and restarts..so far.. i all so looked for codes and it came back with a new one # 33?? I should still probably have the vats bypassed regardless to prevent having to go through all this for a bad connection.
now it starts and restarts..so far.. i all so looked for codes and it came back with a new one # 33?? I should still probably have the vats bypassed regardless to prevent having to go through all this for a bad connection.
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 21
Likes: 0
Yes looks like I did find it. Today it won't start again and the VATS module is back to giving off incorrect volt. = bad module!!
I now need to burn a chip that ignore VATS and install it to my ECM.
Any one know of A person/ place in northern California that can do it???
I now need to burn a chip that ignore VATS and install it to my ECM.
Any one know of A person/ place in northern California that can do it???
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 21
Likes: 0
See this is my first corvette and i never knew that LT1 was 92-97. the engine is a LT1 383 so the previous owner had a engine swap preformed and much to my delight. I checked the ECM part number and it does not match the year 88, so presumably it was upgraded to match the year of the engine. it is a AC-Delco ECM Re manufactured one. Funny you are the only person to have caught that the LT1 does not match my Year. regardless of all that the problem Is VATS and i am having that bypassed and will hopefully be done with it.
