07-21-2016, 07:21 AM
Let me first layout what I have. It's a 1988 1/2 Samurai that has been converted to fuel injection with a 1989 tracker system. I drove it home when I bought it (@50 miles) and it was not driven again except for starting it and moving around in the yard so I could mow around it. I've spent the last 18 months or so completely restoring it from the frame up. Last week I finally finished connecting the wiring back and filling it with fluids to try to get it started. When I turned the key on, the motor turned over good but there was no fuel to the TB. Poured fuel into the TB and the engine will start and run until the fuel burns off. Noticed that the fuel pump didn't run until the key went from "run" back to "accessory". It would not run in "run" or "start". Sent my ECM to Digitalguy in MN, and got it back today. While I waited for him to get it done, I removed my dash and rechecked all the wires. I took the harness out and chased/checked all the connectors against the wiring schematic, tagged them, and reattached it to the back of the dash just like it was from the factory. Put the ECM back in, double checked my connections, hooked up the battery, turned the key...same problem. But, I've found out that not only does the pump run when the key is returned from "run" to accessory, it runs when the ignition is turned off. It even runs when I unplug the ignition from the harness.
So to recap:
Ignition off - no pump
Ign. accessory- no pump
Ign. run- no pump
Ign. start- no pump
Ign back to run- no pump
Ign. back to accessory- pump runs
Ign. off- pump runs
Remove fuse -pump runs
Disconnect ignition - pump runs
Unplug fuel relay - no pump
Unplug harness from ECM- main relay pulls in just like it's supposed to and doesn't go off as long as the key is in run or start position. But as soon as the key is in accessory, main relay opens.
Started checking voltage. So I put the ECM back in. Turned the key to run then off again to get the fuel pump running. Put my meter probes into the main relay connector at the black/white wire and then to ground. As soon as the negative probe was grounded both relays opened (main and fuel). Did the same thing on the fuel pump relay. Put the +probe into the connector at the black/white wire and then touched my - probe to ground and the relays opened. The opposite side of the main relay coil is a black wire that goes straight to ground. The opposite side of the fuel pump relay coil is a pink wire that goes to the ECM. I cut the pink wire and then turned the key to run and the main relay pulled in just like it was supposed to. The fuel pump relay though didn't pull in. I grounded the pink wire that I had previously cut coming off of the fuel pump relay (kept the pink wire from the ECM hanging loose) and it too then started to work exactly like it was supposed to. So it seems the culprit is the pink wire. When I check voltage on the pink wire to ground I get 8.5v with the ignition on. I assume there should be no voltage on the pink wire since it is the ground leg for the fuel pump relay, but I don't know what goes on after it goes into the ECM.
While I had the pink wire grounded and the fuel pump running, I tried to start the engine but the injector wasn't spraying any fuel.There are no sensors that detect fuel pressure so I thought the injector would fire regardless of fuel present. Using a 12v bulb and socket from an old turn signal, I rigged up a noid light and wired it to the red and yellow wires that connect to the injector, but I didn't get any light when I cranked the engine over. So it looks to me like I still have a ECM problem. Any suggestions? Open to any ideas.
So to recap:
Ignition off - no pump
Ign. accessory- no pump
Ign. run- no pump
Ign. start- no pump
Ign back to run- no pump
Ign. back to accessory- pump runs
Ign. off- pump runs
Remove fuse -pump runs
Disconnect ignition - pump runs
Unplug fuel relay - no pump
Unplug harness from ECM- main relay pulls in just like it's supposed to and doesn't go off as long as the key is in run or start position. But as soon as the key is in accessory, main relay opens.
Started checking voltage. So I put the ECM back in. Turned the key to run then off again to get the fuel pump running. Put my meter probes into the main relay connector at the black/white wire and then to ground. As soon as the negative probe was grounded both relays opened (main and fuel). Did the same thing on the fuel pump relay. Put the +probe into the connector at the black/white wire and then touched my - probe to ground and the relays opened. The opposite side of the main relay coil is a black wire that goes straight to ground. The opposite side of the fuel pump relay coil is a pink wire that goes to the ECM. I cut the pink wire and then turned the key to run and the main relay pulled in just like it was supposed to. The fuel pump relay though didn't pull in. I grounded the pink wire that I had previously cut coming off of the fuel pump relay (kept the pink wire from the ECM hanging loose) and it too then started to work exactly like it was supposed to. So it seems the culprit is the pink wire. When I check voltage on the pink wire to ground I get 8.5v with the ignition on. I assume there should be no voltage on the pink wire since it is the ground leg for the fuel pump relay, but I don't know what goes on after it goes into the ECM.
While I had the pink wire grounded and the fuel pump running, I tried to start the engine but the injector wasn't spraying any fuel.There are no sensors that detect fuel pressure so I thought the injector would fire regardless of fuel present. Using a 12v bulb and socket from an old turn signal, I rigged up a noid light and wired it to the red and yellow wires that connect to the injector, but I didn't get any light when I cranked the engine over. So it looks to me like I still have a ECM problem. Any suggestions? Open to any ideas.