OBD - Team Camaro Tech
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post #1 of 22 (permalink) Old Nov 1st, 01, 06:29 AM Thread Starter
 
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how can you tell what kind of obd system you have?i have a 94 z28 and thought i had obd1, but when i attempted to jump A to B it just turned the fan on so i'm not sure.i didn't see anything about obd on the emissions sticker.
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post #2 of 22 (permalink) Old Nov 1st, 01, 07:39 AM
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Mark
 
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If you have a 16 pin (although only 8 have terminals in them) connector that looks like a serial port connector on a computer then you have OBD-2.

95 model year camaros were the first to be OBD-2 compliant though.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
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post #3 of 22 (permalink) Old Nov 1st, 01, 07:49 AM Thread Starter
 
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mine is 12 pin 4 terminals.i don't understand why i can't activate it by jumping a and b.
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post #4 of 22 (permalink) Old Nov 1st, 01, 02:16 PM
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12 pin connectors indicate OBD1.

Are you calling terminals 1 and 2 the two terminals in the top row farthest to the right as you look at it? The corner one is ground and should have a black wire on it.

With the jumper installed you need to turn the Key on without starting the car to start sending the codes.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine

[This message has been edited by Mark C (edited 11-02-2001).]
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post #5 of 22 (permalink) Old Nov 1st, 01, 07:00 PM
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When you turn the key on with engine off does the check engine light come on? Or is the light on but won't flash codes when you jump a-b?Let me know if it's the 2nd question and I'll give you things to check.
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post #6 of 22 (permalink) Old Nov 2nd, 01, 03:44 AM Thread Starter
 
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when i jump a-b and then turn the ignition on, the fan comes on but the check engine light doesn't.
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post #7 of 22 (permalink) Old Nov 2nd, 01, 03:52 AM Thread Starter
 
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i dont see a black wire.the two terminals in the top right corner have gold ports(i don't know what to call them)in them.on the bottom in each corner i have two silver ports.thats all the ports there is.the other terminals are empty.
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post #8 of 22 (permalink) Old Nov 2nd, 01, 05:03 AM
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please answer my first question and not worry about jumping anything at the moment.When you turn on the key with the engine off does the check engine light come on???If not you need to see if the bulb is burnt out.The bulb should always light up this way.
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post #9 of 22 (permalink) Old Nov 2nd, 01, 07:01 AM
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Your suposed to jump A-H.

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post #10 of 22 (permalink) Old Nov 2nd, 01, 10:37 AM
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I haven't done a Chevy by Jumpering ports, only F%@#'s (please forgive me). My current computer driven car has OBD-2 and I have a PC program for getting the codes out on my laptop. Fords don't flash the check engine light, you need to have an analog voltmeter connected to a test port, but when you start the test in one of those cars, you get a whole bunch or relays and other devices switching on and off before the voltage pulses on the test terminal start. Maybe you just need to wait 10 or 20 seconds for the test to start.


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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
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post #11 of 22 (permalink) Old Nov 2nd, 01, 01:30 PM Thread Starter
 
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yes the service engine soon light does come on when you turn the ignition on
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post #12 of 22 (permalink) Old Nov 2nd, 01, 04:03 PM Thread Starter
 
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i don't know if this helps anybody but my obd is set up like this - - - - B A
G - - - - L
letters indicate ports. is this normal for a 94 z28?
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post #13 of 22 (permalink) Old Nov 2nd, 01, 07:46 PM
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a to h joecool??? I don't think so.It's always a to b.St20 a-b is in the top right.Is the light on while your running the engine and that is why your trying to get codes or is the light off when the engine is running?If your trying to get codes by jumping a-b and the light is not flashing then one of two things is happening.Either there is a short to ground in cicuit 419 which is a brn/wht wire connected between computer terminal a5 and the check eng light bulb or there is an open in circuit 451 which is the wht/blk wire between computer terminal a9 and the b terminal of data link connector where your jumping a-b.B should have 5 volts on it and A is a ground.To see if 419 is grounded disconnect both ecm connecters from computer.If light stays on with key in the on position then 419 is grounded somewhere.If light goes off when you unplug connectors then connect connectors and take a test light and ground it of course then take probe end and touch it to backside of connector 451 right at computer.If check engine light now starts flashing then check 451 wire all the way from computer to data link connector to see if its open.Then do the same with the A wire from data link connector all the way to computer to see if its open.If these wires have ( A -B) no opens from data link connector all the way to computer and circuit 419 is not grounded somewhere and the check engine light is on with key on eng off and won't flash then you have a prom or computer problem so CHECK all those things FIRST before coming to a computer being at fault.Now my fingers hurt from typing. I hope I've been some help.Let me know what you find.Oh yea and don't have A-b JUMPED together when doing these tests.
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post #14 of 22 (permalink) Old Nov 4th, 01, 10:34 AM Thread Starter
 
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the light went off when i unplugged the connectors.where exactly do i nedd to test at?(which connector)i don't know if this means anything,but the white and black wire from B on the data link connector runs into the BLUE connector(plug) on the computer into the hole marked 20.
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post #15 of 22 (permalink) Old Nov 4th, 01, 06:11 PM
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Okay by unplugging the connectors and having the light go out we can eliminate the short to ground I mentioned.Now as I said above take a test light,ground the clip to "A GOOD GROUND" then probe the terminal at the B wire at the computer with the connectors plugged back in.Get what I mean??Where that wire from 'B'on the data link connector enters the computer you are going to touch the test light to the backside of the wire connector where it enters computer.We are eliminating that whole data link connecter and making our own A-B connection by using a test light.If the check engine light now starts to flash you need to find out which of the two wires is open,either it's 'A' or "B".If the light still does not flash and your positive the test light has a good ground then theres a prom or computer problem.I also need to STRESS this.When working on your computer never touch terminals with your fingers.Sliding back and forth on your seat builds up to 5000 volts of static electricity which will DESTROY that computer.It's a good idea to wear a static strap or at least touch your finger to a good ground from time to time to discharge any static electricity.

[This message has been edited by sschevyfan (edited 11-04-2001).]
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