GS300 1996 Start Up Issues Help Needed To Save Car!

[J4AVX]

Hi All

I'm in need of desperate help to save my beloved GS300 sport 1996 MK1.

The car starts and cuts off within a few seconds.

Been with a mechanic for 2 weeks and no joy.

I have changed the following but still issue persists!

Distributor

Crankshaft sensor

Ignition coil pack

Ignition ignitor 

Sparks

Can anyone help or recommend anyone who could look at this?

I really want to keep her alive and on the road but I've hit a brick wall! I don't want to end up selling her for parts.

Any help is appreciated.

It's  GS300 1996 mk1 sport. 2JZ GE engine. 

[Jon Dee]

Don't have any knowledge specific to your car. But generally speaking, an engine that starts and runs for a second or two and then cuts out like the key was switched off, is missing an "engine running" confirmation signal.

On AFM engines it can be a switch in the AFM that closes when the flap inside opens far enough to indicate airflow into the engine. When the switch closes it provides a ground for the fuel pump relay to keep the FP running. Open the switch and engine stops. Often there is a FP pin in the diagnostic plug (pre OBD2 cars) that can be bridged to ground to force the FP to run if it seems that fuel cutting off is your problem. With this system there is a ground wire from the AFM plug to chassis ground. If this ground is faulty/disconnected/broken/badly corroded it will cause a problem

On MAP engines the igniter supplies an ignition fired (IGf) signal to the ECU to confirm that the engine is running. If the ECU does not receive an IGf after sending a certain number of ignition triggered (IGt) signals to the igniter, it cuts the ignition. As you have replaced most of the ignition components and the engine actually runs briefly, the only thing left to check is continuity on the IGf signal wire to the ECU.

Cheers...

[J4AVX]

Thanks Jon Dee. I will pass this info onto my mechanic.

My last option to consider is buying another GS300 and doing a full engine and electronics switch over.

It will cost me some money but its a car I want to keep alive 

[ColinBarber]

You should check for stored error codes. With the ignition on you should short pins TE1 and E1 on the diagnostic socket and count the number of flashes from Check Engine light.

If system is operating normally (with no detected faults), the light will blink continuously about 2 times a second. Otherwise, the light will blink a number of times equal to the trouble code as follows:

         The light blinks only (.5 second ON, .5 second OFF) when indicating a number.

         The light will be OFF for 1.5 seconds between the first digit and the second digit of the code.

         If more than one code is stored, the light will be OFF for 2.5 seconds before the next code is displayed.

         Once all code(s) have been displayed, the light will be OFF for 4.5 seconds and then the whole sequence will repeat.

[J4AVX]

Hi Colin. Thanks for your reply.

The mechanic did a diagnostic test (the old school blink test). No errors came back at all. I was hoping this would pick something up but no joy sadly 

[ColinBarber]

Can't remember on the series I but does it has a security light on the dashboard, and if so does it go out when the key is inserted to indicate the immobiliser has been disabled?

When it starts, are you able to rev the engine? Is it cutting out only on idle?

If you aren't getting an error code then the crank sensor is probably ok. Do you know if plugs are still sparking when the engine dies?

[J4AVX]

1 hour ago, ColinBarber said:

Can't remember on the series I but does it has a security light on the dashboard, and if so does it go out when the key is inserted to indicate the immobiliser has been disabled?

When it starts, are you able to rev the engine? Is it cutting out only on idle?

If you aren't getting an error code then the crank sensor is probably ok. Do you know if plugs are still sparking when the engine dies?

Yes security light goes out, we don't believe it to be an immobiliser as the start starts and can give it a few revs before it cuts out. 

Once it cuts out then there's no sparks.

Does you or anyone else know if I buy a replacement ECU module, does it need to be reprogrammed?

The conclusion so far is its some sort of signal issue somewhere.

My mechanic has given up on it and my only option is now to book it in at main Lexus dealers....

 

[J4AVX]

Hi All.

The cars back at home now parked up. Mechanics gave up on it and sadly no body has been able to diagnose the issue.

Its off road now and will try and see if I can get some other mechanics to look at it but for now taking a little break.