RADSC

My 92 Manual SC300 starts up fine cold. However, If I drive for about five minutes and shut off the engine and try to restart, it stalls. The engine rpms to about 1500 then stalls. It does that usually 3-5 trys before maintaining a good idle. I've checked the engine codes and it is normal. NO codes. ?:? I have no clue? I wanted input from you guys before taking the plunge to the LEXUS dealer, $100 per hour.

I've heard fuel pump ecu can be a problem, but wouldn't that give you an engine code? THANKS for ANY input.

Soarer-1JZ

Does the sc300 have a mass air flow sensor..? If so
it could be bad, or you could have a leak between the sensor and throttle body.
Also, if these cars have a crank trigger sensor, it too could be going bad...

UJAKOB

Hi, Hope your car is fine again.
As I have the same problem with my SC 400 can you give me some help.
What was th reason in your case. Please send me your answer also to ujakob@access.ch
Many thanks

RADSC

FIXED IT!!!!

What was confusing me all this time was the NORMAL engine code I was getting. I finally read the manually carefully. When the Fuel Pump ECU malfunctions, there is NO engine code. The code is NORMAL. NO one stated this fact in the prior threads. Anyways, the car runs GREAT. Back to normal.

I'd like to thank London Bill (? i think that is who posted about bypassing the FP ECU).

So to wrap this up:

Problem: Engine stalls on HOT start ups. Cold start ups are fine.

Fact: SC 300 & 400 (prob gs, is, ls also) have FP ECU's which regulate voltage to Fuel pump from 8 to 14 dc volts ( low during idle, hi, hi lo during start up and acceleration)

Fix: Bypass FP ECU by connecting two big wires which are in the plug going to the FP ECU (can't remember color, but they are next to each other and largest in caliber)

Thanks to Club Lexus and it's well informed members. SAVED me $$$ not bring to the Lexus dealer to diagnose.

This must be VERY COMMON problem with an EASY fix.

reamemiya

iTrader: (1)

you need professional help... i recommed my therapist... naw yeah go get it checked out don't want wrong info.