Difficulty starting
 

My son has an 87 Turbo Supra. It starts well after being run, at least for a few hours thereafter.
If it left longer than that (say overnight) it takes several attempts before it catches. It has new plugs and we have even tried leaving the ignition in the on (but not start) position thinking it may be the fuel pump. This doesn't make a difference. My son thinks it could be the cold start injector. Anybody have any thoughts.
Thanks

The fuel pump only runs in the 'start' (cranking) position until the motor starts.

The cold start injector only operates below 66* (overnight?)

It also shuts off after 12 seconds(accumulated) of cranking, to avoid flooding.

You may have an injector, or the check valve in the tank, bleeding down the fuel pressure.

Perform a fuel pressure test to find out. A shop may be you best bet there, as you need the test equipment.

there is also a cold start switch/sensor aside from the cold start injector
it's mounted upfront near the thermostat housing .

i wouldn't just replace the cold start injector , i would take it out and try to get it cleaned before actually replacing it

http://www.cygnusx1.net/supra/librar.../ec/EC_04.html

see the BVSV in the diagram , thats not the cold start sensor but the sensor is just below that BVSV

More things you could do
 

Just for troublshooting sake...I would also check your fuel filters, see if they are clogged, also run some fuel injector cleaner with the gas for a couple tanks. That should HELP to tell you if it's injectors, or at least if it is a dirty injector.

It could also be a worn out fuel pump, but then it would likely run crappy all the time. I agree with the first posts here, it is likely an injector clogged, or its something that is causing you to have low fuel pressure on a cold start.

Well I REALLY hope your son finds out what is wrong with it, and gets it fixed. Owning a supra is a hobbie in its self. You have to enjoy working on them, because regarless of how "Excelent" people say their supra's run...SOMETHING will always be there to piss you off when you don't want it to.