— Thanks to @satchel , this has finally been fixed!
Hey Mudders,
Revisiting this issue a year later. I'm having an intermittent high-speed fuel pump circuit break that I need advice with. I had posted about this a while ago in another thread before I realized the issue was related to an electrical issue rather than a mechanical issue. Here's the original thread FZJ80 Won't Start
So, here's what I know --
Here's the literature I have currently:
this has all kinds of stuff, but I cant figure out how to make sense of it haha 1996 Land Cruiser FZJ80 Full Wiring Schematic
Any additional help or experience would be awesome!
Hey Mudders,
Revisiting this issue a year later. I'm having an intermittent high-speed fuel pump circuit break that I need advice with. I had posted about this a while ago in another thread before I realized the issue was related to an electrical issue rather than a mechanical issue. Here's the original thread FZJ80 Won't Start
So, here's what I know --
- The fuel pump has two speeds/pressures -- 1) low-speed and 2) high-speed.
- The high-speed circuit is activated under these two conditions :
- While the car is cranking to initiate engine start
- Under heavy acceleration/high RPM's - roughly 3200-3800 RPM's
- The issue started randomly after I pulled off of the highway onto a rough gravel road.
- I made a fast turn across traffic and slammed on the gas pedal and the engine/RPMs cut out immediately. I took my foot off the pedal and my RPM's/engine came right back to life.
- I've replaced:
- Fuel pump relay with OEM part
- Idle control valve with OEM part
- EFI relays under the hood and in drivers-side kick panel
- The high-speed circuit relies on ground contact being made inside the ECU
- I've taken apart the ECU and checked all circuits to make sure moisture/corrosion wasn't causing poor grounding and everything was tight and dry. No corrosion or burnt processors or anything at all.
- I've checked all of the in-line molex circuit connectors I could access.
- I installed an in-line switch to manually activate the high-speed fuel pump circuit.
- The manual circuit wiring goes from: Positive+ battery terminal --> manual switch in cabin --> high-speed circuit connection on the Fuel Pump Relay
- I flip the switch on to start the car and while on the interstate, but I can turn off the switch immediately after the engine starts because the circuit switches to the low-speed circuit which works fine.
- It will randomly choose to work fine and will start up without me having to turn the switch on, so whatever is causing the high-speed circuit to break is intermittent but rare.
- Extreme heat and extreme cold don't seem to have any effect on whether the circuit decides to work on its own or not.
- Possibly related electrical weirdness - but had been happening for a year+ before the fuel pump issue started but...
- When my headlights are on, my radio backlight turns off
- UNLESS it's below zero degrees Fahrenheit, then the backlight stays on until it warms up.
- Every other backlight on my dash and climate control console come on as expected when I turn the lights on - this includes the ashtray light and cig lighter halo.
- When my headlights are OFF, my radio backlight comes on.
- When my headlights are on, my radio backlight turns off
Here's the literature I have currently:
this has all kinds of stuff, but I cant figure out how to make sense of it haha 1996 Land Cruiser FZJ80 Full Wiring Schematic
Any additional help or experience would be awesome!
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