92 Sc400 Engine Starts And Then Dies Erratically

[GFunkError]

This has happened 3 times in the last 3 days. I start the car and then 5 secs later it dies. Then I start it up again and rev it a bit and its fine...Indicator of future trouble?

Any clues?

[daveyjones]

This has happened 3 times in the last 3 days. I start the car and then 5 secs later it dies. Then I start it up again and rev it a bit and its fine...Indicator of future trouble?

Any clues?

You may want to check the TPS Sensor. Although the Engine light should come on if this is the culprit.

[AWJ]

Fuel pump ecu. Try a search of this forum from all dates and results - I have posted links to this issue in the past. This is the symptom of this item. It could be something else as well though.

[Lex Luthor]

If it's not the pump ecu (which it probably is, AWJ is familiar with it, I just ran straight 12v :) )...then check the connection on both coils. We'll proceed from there.

[grod01]

i had that same problem a while ago. i bought a new battery and pulled the cable from off of the battery and it would not stay on there and it keptt cuttin off. turn the car on and keep your foot on the peddle for about a min. but make sure your battery cables are on the battery tightly.

[soarer479]

sounds like an air or fuel problem to me

[gogo_sc300]

I have had the same problem kind of. When I drive and let the car get hot then try to restart after it has only been sitting a little while it will turn over just fine and fire then after about 5 sec it will die. If I rev and hold the car at about 6 grand I can feel the engine try to shut off but it doesn't. Doesn't happen at all on a cold start. BTW it's happening on a 92 sc300

[AWJ]

Fuel pump ecu

http://us.lexusownersclub.com/forums/index...l=fuel+pump+ecu

http://us.lexusownersclub.com/forums/index...showtopic=6263&

[SKperformance]

clean your idle air control valve

[2XLexV8]

Good Evening;

Couple of questions (in order):

- Is it hot outside (near 100F), or is the car sitting in the direct sunlight?

- Is the clip that holds the fuel lines to the driver's side fenderwell broken?

- Have you checked the valve in the fuel cap?

It could be vapor lock, where the gas vaporizes in the fuel line and the air bubble won't let the fuel pass.

I had this problem, solved it by reattaching the lines to the fenderwell, and wrapping the lines with foil. Hasn't happened since. I'll take a stainless heat shield and modify it later, and mount it to the holes already in the fenderwell.

Feedback always welcome :D

[GFunkError]

Thanks a lot for the replies guys. Fortunately since I had this post, I have not had this problem.

The car was sitting in direct Houston, TX sunlight where temp inside the vehicle is over 100F.

Not checked the other stuff. I do rev the engine once every time I start it and it has never happened again.

[mack71]

I had this problem on my 1992 sc400 it was the idle air control valve. This part is $668.00 from the dealership. Mine also went away for a little while but then came back where it would take me 15 mins sometimes to start my car. It always acted better when it was cool and less humid outside. I eventually had to replace the idle air control valve. :o

[2XLexV8]

Good Evening,

Since my last post, the problem came back.

Replaced the fuel pump ECU, good to go.

Thanks AW3, he called it some time ago.

As to why - When the car gets hot, the fuel pump ECU is supposed to increase fuel pump pressure and overcome fuel perculation in the engine.

Bad ECUs don't do that. But relieving the pressure in the tank will allow you to run sometimes.

Troubleshoot the ECU before replacing the fuel pump.

In eiter case, the entire rear seat comes out.

Good Luck

[LLS]

Just for future reference, one of the most simple things to check that can cause the same headaches and cost nothing to repair is the actual intake tube itself. The rubber dries out after a while and you might even go outside right now and grab the tube and flex it only to find you have cracks that are robbing you of performance.

The fix is up to you, however after cleaning it with alcohol you can epoxy the area in question, use black electrical tape, or simply choose to spend money and replace it.

Having an air leak on the tube can cause rough idle, poor starting, hesitation, lower fuel mileage, and poor performance overall. If your car is over 8 years old, the smaller cracks in it are certainly there and you can benefit from changing it.

Food for thought before you make your way to the more expensive items. Had this user not needed an ecu and bought one, it would have been ugly.