Supra dying with a touch of the gas, whatcha think?

[KevinM]

I usually don't ask too many questions, but don't want to waste time chasing the problem, so I figured I'd ask and see if anything else made sense.

Here's the details.

Just finishing up putting together another Supra, 89. Put my old motor in it (from my 90). Nothing changed as far as timing belt/timing. Only thing not done is the exhaust (open 2.5" dp) - waiting for a cat.

It's not throwing any codes. Was throwing air signal, but a different afm, and we're good to go.

It'll start, idle surges up to appr 12-1300 rpms. Will sit there for a minute and eventually die. If I touch the gas in any manner, it'll stumble and die almost immediately. Changing the CPS timing doesn't change much.

Mainly, I'm thinking IC piping leak since it seems to die out with anymore fuel.

Any other ideas before I start tearing around on the IC piping?

Thanks
Kevin

 

[adampecush]

sounds like a big air leak to me.

 

[billspreston01]

I vote big air leak or AFM (if I unplug my AFM I get the same issues...it'll idle, but if i touch the gas it dies)

 

[noah89t]

air leak, check your intake gaskets. you can have someone try to keep it running at a constant rpm while you spray something like carb cleaner on the gaskets and notice high rpm's if it leaks

or make a leak tester

 

[Shima]

i had that issue. first i checked AFM then i checked TPS then i noticed i had no fuel in the car it would start but the moment i touch the gas it died hahaha. my 3 check list

 

[shaeff]

Do you have a fuel pressure gauge?