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Hi. Not sure what year the motor is because its in a sand rail. Most likely its a 2001. I do know that its a vortec 4.3 v6. Just spent all my money on this 25 year dream, haven't even driven the thing and already having issues. Ran cherry when I bought it and after about 2 weeks of starting it up when friends came by to check out my new toy, the idle starts to intermittently surge. I tried not only hooking up my OBD1&2 scanner but my buddies scanner too and both of them are unable to link up to the computer. Can someone tell me how to troubleshoot this? Scanner powers on when buggy key is turned but cannot link to ECU
Last edited by Hunter Whiteside; 02-21-2021 at 08:57 AM.
Reason: Forgot to mention something
Double check that the serial data wire is in the right place on the OBDII port, and hopefully hooked up to the computer as well...
On the OBD port, it should be a wire (usually purple, but could be any color really) on the #2 pin as seen below (this is as you would be looking at the plug from the side where you're plugging in a diagnostic tool)
Double check that the serial data wire is in the right place on the OBDII port, and hopefully hooked up to the computer as well...
On the OBD port, it should be a wire (usually purple, but could be any color really) on the #2 pin as seen below (this is as you would be looking at the plug from the side where you're plugging in a diagnostic tool)
What type of computer is running the system
The standard 411 PCM style?
Or one of the older styles?
Thank you sir. All wires are in the correct spot on the OBD port. Took some voltage readings at each pin with car in the on position. Not sure what these readings mean. Any help is very much appreciated🙏🏼
Test for GOOD continuity to ground on pins 4&5 in the OBD2 port. A typical multimeter will give you a continuity tone with anything below 50ohms, but it should be much lower than that for good connections.
Pin 16 should would run straight to the battery in a factory configuration, but being connected to an ignition source isn't going to affect things much.
Pin 2 can run to any one of the class 2 data connections on the ECM; two of which would be on connector 4 (BLACK) pins 11 (dark green wire) or 14 (yellow wire) [as referenced from my 2000 service manual anyway]. On a 2000, the yellow wire from pin 14 would typically run to the BCM which I'm not sure your rail has and the dark green wire from pin 11 would run to a splice pack and that splice pack would branch it out to the DLC, BCM, as well as other class 2 data bus communication devices. A 2000 has the same ECM configuration as you have shown in your picture.
You're going to need to verify that each pin on the DLC is correctly routed before you'll be able to move forward. The fact that the tool powers up, I'm going to assume that you have power & ground appropriate, but it is still good to double check.
The serial data wire is going to have to be verified from point to point, i.e. from one end of the wire at the DLC to the other end of the wire where ever it connects. You could try pulling the ECM connector C4 and testing continuity on pins 11 or 14 from pin 2 at the DLC. If you find continuity to one of these pins you should be good to go. If not, then you need to make some wiring changes to get it connected, IMO. That will require pulling the loom apart to get that wire out and spliced in appropriately.
What's the chance that's a 95 computer? Maybe someone could verify, but weren't those OBDI, or OBD1.5 as it's referred to as they started using the OBDII diagnostic port even though the computer system was still OBDI? Could be why an OBDII reader can't make since of it.
Test for GOOD continuity to ground on pins 4&5 in the OBD2 port. A typical multimeter will give you a continuity tone with anything below 50ohms, but it should be much lower than that for good connections.
Pin 16 should would run straight to the battery in a factory configuration, but being connected to an ignition source isn't going to affect things much.
Pin 2 can run to any one of the class 2 data connections on the ECM; two of which would be on connector 4 (BLACK) pins 11 (dark green wire) or 14 (yellow wire) [as referenced from my 2000 service manual anyway]. On a 2000, the yellow wire from pin 14 would typically run to the BCM which I'm not sure your rail has and the dark green wire from pin 11 would run to a splice pack and that splice pack would branch it out to the DLC, BCM, as well as other class 2 data bus communication devices. A 2000 has the same ECM configuration as you have shown in your picture.
You're going to need to verify that each pin on the DLC is correctly routed before you'll be able to move forward. The fact that the tool powers up, I'm going to assume that you have power & ground appropriate, but it is still good to double check.
The serial data wire is going to have to be verified from point to point, i.e. from one end of the wire at the DLC to the other end of the wire where ever it connects. You could try pulling the ECM connector C4 and testing continuity on pins 11 or 14 from pin 2 at the DLC. If you find continuity to one of these pins you should be good to go. If not, then you need to make some wiring changes to get it connected, IMO. That will require pulling the loom apart to get that wire out and spliced in appropriately.
Thank you sir, I verified continuity from pin 4 to ground and pin 5 to ground. Pin 16 has 11.91 volts. I'm ganna need some help from a friend to verify the rest. I just don't know enough about this. I appreciate your time. If we figure it out I will post what we found here
What's the chance that's a 95 computer? Maybe someone could verify, but weren't those OBDI, or OBD1.5 as it's referred to as they started using the OBDII diagnostic port even though the computer system was still OBDI? Could be why an OBDII reader can't make since of it.
02-21-2021, 08:48 AM
Scanner won't link to computer
