1JZ-GTE Soarer runs for 7 sec, then dies - where to start?

[PT1]

Ah the weekend will be fun. Thanks boys.

Elmo - Skylines are a piece of cake to work on compared to this thing! (GTR not included)

[CrUZida]

Typical symptoms of a dying fuel pump ECU in a Soarer
Simple diagnosis is in the engine bay diagnostic connector, bridge FP to B+ terminals with a thick paperclip to bypass the FP ECU and try starting again.

Listen to the man.

[PT1]

Are the FP and B+ terminals on the diag plug marked or do i need a wiring diagram to know whats what?

[CrUZida]

They are marked.

[Soarer_D00D]

Silly question, but does it have enough fuel?

[PT1]

Yeah. Thought it was that. Was running very low. Put 10L in, then another 5L. After filling with the 5L is when it ran for a while 2 days ago, then would only pull 7sec again and again.

Sadly it's a question you have to ask though. When I was running a dealership in Sydney noone could fix this CRV or HRV honda gearbox, kept slipping intermittently, acting wierd. Drove it round the block, was a bloody CVT. Local auto shop didn't even pick up on it.

[sideshow]

does it stop straight away or slowly dies

usually if its fuel related it will die slowly

if theres a lossin power to either ecu coils etc then it will stop suddenly

ive had 2 soarers play up with bad relays or connections on relays

one used to get to 6 or 7 kph then suddenly stop

it was loosing power to ecu

so if its not fuel related then u need to check powers to all main things like coil and ecu

its a pain to check anyhting on a soarer
as they are fukt design with so much electrical shit any work on them takes ages

id never own one thats for sure even it was for free heheheheheeh

[PT1]

Progress! Thanks for all the ideas guys. 1st thing I tried showed change.

Bridging FP to B+ on the diagnostic connector in the engine bay allowed the engine to run.

After the bridge wire was removed, the engine died within about 5 seconds each time.

Next step? What the hell is a fuel pump ECU, where is it etc? Why can't it just use 1 normal ECU for the EFI like a normal person.?

[sideshow]

soarers run a fuel pump ecu behond the passenger side rear section of trim

it controls ho and low speed depending on signals form the ecu

it coul dbe that it could also be the circuit opening relay if its got one plus i thik they also have a fuel pump relay

as i said they are a pain to work with
very over engineered pieces of u know what

so now you have to see if signals are there from ecu or relays

another thing to check is relays earths ive had them have bad connections in the past
due to the battery throwing acid everywhere around the base of fuse box

[PT1]

So - is this car just running on the fuel injected during cranking at start up, or does it run the fuel pump with another ECU/trigger for 5-7 sec after startup before using a relay to switch control to the FP ecu?

Just trying to narrow things down logically before I go on a wild goose chase. We have a running car now, so would like to figure out exactly what the FP and B+ bridging would have eliminated as possible causes.

[manny]

The bridge between FP and B+ bypasses the fuel pump ECU altogether and runs 12V directly to the fuel pump.
It's meant to be a temporary diagnostic fix as it will run 12V to the pump constantly even if the engine isn't running, like when you crash the car...
The fuel pump ecu varies the fuel pump voltage between ~9 and 12 volts during various running conditions via a connection to the EFI ECU.
Currently your FP ECU appears to be initially priming the pump but then failing to maintain power to the pump once the engine fires.
There's no COR or fuel pump relay - the fuel pump ECU and EFI ECU manage all the fuel pump control functions on a Soarer.
The fuel pump ECU can't be readily repaired, so replacement at ~ $200 for a new one or trying your luck on a second hand one is the normal option for the hundreds of prior Soarer onwers in the same position as you.

[sideshow]

+b is power frommain relay
it isnt battery power
so pump will only work when ecu is on

are they really 200 bucks new i would expect more

i know the 2nd hand one i have is worth 150 to 200

[cambelt]

the supra one doesnt seem to blow up at all , maybe get one of those , staight plug in . id say more like $420 for a new one .
Dave

[CrUZida]

As far as I know they are all the same part number, maybe they updated something internally between the Soarer being released, and the Supra being released.

$270 new from Rush Imports (when the website is back up)

[PT1]

Thank you very much guys, you have made a potentially painful task exteremely easy. The knowledge and detail has been fantastic. I'll track down a replacement FP ECU.

Rep points ahoy.