glfredrick
NAXJA Forum User
- Location
- Louisville, KY
We have an 86 4 cyl. that has a very strange electrical issue that we cannot track down.
The fuel pump gets no power through the electrical harness.
Now, that should be obvious -- track down where it comes from, and make sure that it is getting power, ground, a good pump, etc. -- We did all of that...
Here's where it gets even weirder. In an attempt to bypass the electrical harness and send power directly to the tank pump, we ran a jumper wire direct to pump from the battery (just a test). The pump works fine -- BUT -- that kills all the electric to the ignition system. Engine cranks, but no spark.
So, we can have spark -- but no fuel -- or fuel -- but no spark.
This even happens when we totally isolate the fuel pump from the rest of the vehicle wiring harness (as in run direct and seperate wires to the pump).
Anyone have a clue?
Right now, we've got the ENTIRE electrical system unwound, uncovered, and laying loose -- and so far, nothing rubbed through anywhere.
The engine will start right up if we juice it manually, then lay off the pump and allow the spark to fire -- of course, it dies the minute it runs out of fuel.
The fuel pump gets no power through the electrical harness.
Now, that should be obvious -- track down where it comes from, and make sure that it is getting power, ground, a good pump, etc. -- We did all of that...
Here's where it gets even weirder. In an attempt to bypass the electrical harness and send power directly to the tank pump, we ran a jumper wire direct to pump from the battery (just a test). The pump works fine -- BUT -- that kills all the electric to the ignition system. Engine cranks, but no spark.
So, we can have spark -- but no fuel -- or fuel -- but no spark.
This even happens when we totally isolate the fuel pump from the rest of the vehicle wiring harness (as in run direct and seperate wires to the pump).
Anyone have a clue?
Right now, we've got the ENTIRE electrical system unwound, uncovered, and laying loose -- and so far, nothing rubbed through anywhere.
The engine will start right up if we juice it manually, then lay off the pump and allow the spark to fire -- of course, it dies the minute it runs out of fuel.