engine starts and then stalls

[CMcD]

Hows everyone doin?
First off i want everyone to forgive me if i put this post in the wrong place i am very new to this site and this is my first post. I just recently had my timing belt replaced and spark plugs as well. I got a 1993 SC400 and its got 174,500 miles on it but thats not the problem. I drove to NH today and it was fine. I stopped somewhere and shut the engine off. 20 minutes later i attempted to turn the car back on. It would start and quickly shut off again. While starting it it made a wierd noise and then it sounded like the gears were grinding. Tried it again did the same thing. Third time i took the key out put it back in, and then tried to start it again this time giving it gas it ran for 3 seconds then shut off. Did it again and kept it running with gas at 1000 rpm. Ran fine after that. Got home and waited to go out again this time 5 hours and the engine was cold. Turned on then shut off immideatly. Had to do the same thing. anyone know whats wrong?
thanks for the help.

 

[Nick M]

Pull codes first.

An air intake leak will do that. So will a lack of fuel pressure from heat soak vaporizing fuel in the rail.

 

[mdcmotorsports]

Im thinking that you may have a fuel pump/fuel filter/delivery problem.

Sounds almost like its using all the fuel out of the rails and then dies.

 

[era_gb]

Hi. I have exactly the same problem. Did you fix yours?

 

[CMcD]

i didnt really fix it, I brought it to the dealer and made a series of complaints because the problem occured after they worked on it, so i figured they had something to do with it. But i brought it to them and supposedly they didnt touch the car, but the problem stopped occuring after i brought it to them so, either it was a miracle or they are covering something up so they dont look bad. best of luck to you and i hope your problem is fixed. the guys on the site are really informative and very helpful so i would ask them about it, or do what they told me to do.

 

[era_gb]

Thanks. And I am glad your car is fixed! Good luck with it and enjoy!

 

[Peewee]

Open the little diagnostics box on the top of the motor, and put a bridging wire between FP and B+

This bypasses the Fuel Pump ECU which is the most common failure on the SC400/Soarer.

If it runs fine while the bridging wire is in, and dies when you pull it out (you can pull it out while its running), then your fuel pump ecu needs replacing.

 

[era_gb]

Hi. Thanks. But before I damage some electric installation in my car (I do not know anything about cars.... :sadwavey: ) I will add some extra information about my situation. This problem only exists when engine is warm. Engine starts every time but after a few seconds it starts to die (rpm goes down, check engine starts to flash and it dies - even when I am trying to keep the rpm high). I have to try about 5 times. Then it starts and I have no problem at all. No problem on the intersections, when I am slowing down or in any other situation. After it starts it keeps working nicely. Does it still look that I have to try with the suggestion you gave me? Someone said that it is ignition coil problem.... I appreciate your help very much!

 

[Peewee]

Start with what I suggested.
It'll take 2 minutes, wont do any damage (unless you use a really thin wire), and will eliminate something that is very common to fail.

 

[era_gb]

Hi. Today I did this trick. One thing that need to be mentioned is that at the time I performed that test, every time I turned the engine on - there was no problem keeping it on (engine didn't die). I put a bridging wire like you instructed me, started the engine, took the wire out.... and it died. Is it as simple now to conclude that it is the Fuel Pump ECU problem, or I should wait with this test for a time that the engine will not stay on when started?

 

[Peewee]

Yeah, I'd wait for a time when the engine doesn't start.

Mine one day just failed.
Was fine in the morning, then next time I started her she coughed and spluttered then died. Wouldn't start after that.
Put the bridge in, fired straight into life.
Pull the bridge out while running, and she died.

I paid about $180AUD for a new fuel pump ecu.
Hasn't been a problem since.

 

[era_gb]

Thank you for all your help Peewee. But, unfortunatelly, I am in no luck. I went to my mechanic twice this week to show to him my problem, and although I drove for quite a while - I did not have problem starting the engine after few minutes. This week I tried to get to this state (dying warm engine) many times and no success ( :dunno: ). Obwiously I have this problem but it doesn't happen every time. If I decided to replace fuel pump ECU - is there any way to test my ECU that it is faulty? I already took the rear seat apart and I see it under the window. Can a mechanic or Lexus dealer do it? There are these units on eBay but how do I know that they are not faulty as mine? How do I determine for sure that it is faulty unit? Thank you so much! Greg