LT1/LT4 Tech 1993-1997

no signal from MAP or MAF

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Old 10-30-2010, 11:06 PM
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Default no signal from MAP or MAF

i bought a car from a buddy of mine that was running hot and he just new it had a blown head gasket and pulled the motor out.i bought the car taken apart and rebuilt the engine.i now have the engine in and running but is running really rich so rich the engine oil got fuel in it so i changed the oil.anyway i hooked up the scan tool and and the MAP and the MAF were not sending a signal everything else seemed to read fine so i pulled all of the wire loom off and traced the wires with a multi meter and there were not any breaks in the wire i am really puzzled anybody ever had this problem?
 
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Old 10-31-2010, 12:26 PM
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better check the connections on em, have them tested. very unlikely but they could both be failing.
 
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Old 10-31-2010, 03:38 PM
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i have replaced both you can even unhook them and doesnt make a difference either way they just will not send a signal
 
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Old 10-31-2010, 06:48 PM
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if i remember right you should be getting .5 volts from the computer on one of the leads. what year?
 
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Old 10-31-2010, 09:00 PM
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it is a 96
 
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Old 10-31-2010, 11:18 PM
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you need to pick up a factory service manual for your yr. i been lookin for any wiring on it and cant find any.
 
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Old 11-01-2010, 12:29 AM
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yea its about to drive me crazy everything was working fine when he pulled the engine out a couple of years ago i figured a rodent or something may have chewed a wire or two so i stripped all of the loom off and havent found anything cut chewed up or burned.i have swapped computers tested the sensor plugs and they have power and grounds but will not signal the computer the scan tool just reads 0.0 on both i remember having -0.55 volts on one dont remeber which.o2's are working fine tps works fine rpms show everything gives me a reading but map and maf.tommorow i am going to lay a harness and computer from the 94-95 in there and see what happens. i ve already used the headers and y pipe from a 94-95 on the car.this just blows my mind i have done alot of lt1 swaps into a 57 chevy truck a 96 s10 jeeps and had less problems with those than i am having with an engine that actually goes in the same car.i have alldata and factory service manuals and still cant figure i even have a friend with a degree in electronics.we both spent about 10 hours on it this weekend without any luck
 
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Old 11-01-2010, 04:12 AM
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94 -95 is obd1 and 96 is obd2 so i dont know if the wiring are interchangable.
 
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Old 11-01-2010, 10:42 AM
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actually 94-95 are obd1.5 uses obd2 plug it plugs up just fine i am also swapping computer.just some trial and error stuff
 
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Old 11-01-2010, 11:16 AM
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95 has a obd 2 plug and a obd1 computer. 94 is obd1 plug and obd1 computer, 96 is obd2, a different and better system.
 


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