randomjoe

HELP! ok so my 92 Lexus sc400 (i love very much) will every now and then start, run rough, then shortly after die, this will continue until i turn the key to the run position for 30 seconds or so, then crank it over. typically it will start and run great after that, with the exception of a gurgly sounding fuel pump for a few seconds. now, i've had this problem for almost 5 years and i just cant figure it out.

o and it give no codes for anything....


thank!
-Joe

neurocity

iTrader: (17)

Fuel filter....Clogged
Fuel Pump....Maybe Bad

Do a full on tune up. Plugs, wires, caps, rotors, PCV valve, Throttle body cleaner, Fuel Filter. Run some Lucas fuel system cleaner with a full tank of Primo.

ihiryu

iTrader: (7)

agreed. Toyota for some reason decided they'd make a "lifetime" fuel filter, I replaced mine (92 SC400) when I got my car, and I could shake the fuel filter and hear it.

Here's a tip on the fuel filter, just soak it in WD-40 for like a night, cause it was a huge PITA to replace the fuel filter

randomjoe

thanks for all the great ideas guys.
i have replaced the Plugs, wires, caps, rotors.
i will try fuel filter right now.

thanks again
_joe

ttsukamoto

iTrader: (1)

Also might be the Fuel Pump ECU located on the driver side, behind the side panel of the rear seat (under the seat belt). My car just stalled randomly and after checking my ECU I noticed that the capacitors were leaking (mine is a 92 Sc400 also so i guess things breakdown and leak after 17 years). $415 from Lexus here in hawaii, but the car runs like a champ now. Service guy said these fail quite frequently on SC's. Easy part to switch out PM me if you need instructions. Good luck.

ihiryu

iTrader: (7)

you could've bypassed it.... I did when I moved to the walboro fuel pump.

ttsukamoto

iTrader: (1)

Yes, you are correct. I jumped it at the diagnostic port and discovered that bypassing the ECU does work. Since my car is stock I just replaced the computer to get it back to factory.

randomjoe

that sounds more like it, thank you guys very much, i will try bypassing it and see if it helps! i will post if it helps or not.

-Joe

randomjoe

so i have a bad fuel pump ECU! first thank you everyone for saving me another five years of trouble shooting! second, does anyone know where the Fuel pump ecu is located on a lexus ES, they dont have any Lexus SC at the juckyard ANYWHERE! third, does anyone have a fuel pump ecu for me for under $50

thanks again!

ihiryu

iTrader: (7)

just do the bypass, it's not that a big deal really. I have mine bypassed.

randomjoe

with the bypass does the pump run constantly with the ignition on and the car NOT running?

ihiryu

iTrader: (7)

no you bypass the fuel pump ecu. In the back seat, the panel under the quarter window on the driver side has the fuel pump ecu, you rewire it so you don't have the fuel pump ecu. There's a few threads on how to bypass it.

randomjoe

right, i pulled it and put the volt meter on it assuming when i turned the key it would get 12v for a few seconds then 0v till i cranked the car over. in my case i came up with 12v when i turn the ignition to run and it stayed at 12v until i shut the ignition off. made me believe the relay was in the "Fuel pump ECU" and that was my reson for not wanting to bypass it, but i'll check again tomorrow.
to bypass it i just marry the two heavier gauge wires together before the pump ecu?