Uzz31AU

Hi guys, I'm new here, first post!
It's a no start issue...

Just picked up a 1991 UZZ31 Toyota Soarer (sc400) that is having problems and am after some advice on where to start.
I'm currently sick and stuck in bed, so no big rush.

I drove down to the local shop and went shopping, came back and car wouldn't fire. Cranks fine, but won't fire.
After 30 minutes of wondering what I am going to do, the car started again as normal, and I drove home fine.
The next morning the car would not fire again, just cranks...

*Swapped main engine ECU with known working recapped ECU* :No change.
*Bypassed fuel ecu with paperclip from b+ to fp* :No change. (Not working).
*Checked relays (specifically main EFI) and they seem fine. Swapped with other relays, no change.
*Fuel pump does work, but only when using a physical wire attached from the battery to the fuel pump behind rear seat.
*Car will crank and fire, and stay running with a physical wire from battery to fuel pump behind rear seat.

Turns out that I have 10.5V with ignition on in the B+ port of the diagnostic thing; As far as I know, I should be getting 12v, is this right?
Bypassing the fuel pump ECU with FP and +B does not work.
Car has spark, just no fuel.

Last question, will running the fuel pump directly off a wire and bypassing any relays in the meantime have any big issues?


Thanks people.

Chead

Sounds like what this person went through, came across it while trying to solve a no start issue I'm having with a 1993 SC300.
https://www.clublexus.com/forums/per...ee-inside.html

Uzz31AU

Hi mate, thanks for the reply.
I had a read of that before I posted actually, it seems most people with this issue have not reported back with their findings once fixed.
Incredibly annoying.

Sony1492

Figure out if the injectors are firing when you crank, there should be a bunch online about how to check.

If they are then we can assume this is a pump/wiring issue. If they don't then you can look at crank and cam sensor issues, maybe even ignitors.

mrmj2u

iTrader: (2)

Have you checked your EFI fuse? It sounds like you have a short in your system.

Uzz31AU

Just a quick update:
Fuses seem fine, checked with a light. Unsure about EFI relay. Swapped it with headlight relay I think, and fuel pump still did not work.
10.5v through b+ was due to a knackered battery. The indicator light on battery was green, but it had a dead cell.
Put a new battery in, checked wires, everything's fine there. Still no power to fuel pump unless hotwired from battery.

Lost work so cash is limited, hoping to find more work soon!
In the meantime, any more ideas?

*New ECU
*Fuel pump works when bypassing everything and hotwiring it to the battery

Hoping it's just a $30 relay, but after swapping the EFI out with another one it still won't work.

Car's parked in the garage right now, used only when needed for a shop run, and to keep her 'alive'.

Sony1492

You could try bypassing the fuel pump control unit before you replace the ecu

Uzz31AU

In the first post, I mentioned car has a new ECU, and fuel pump ECU was already bypassed.