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Discussion Starter · #1 ·
My 86 Supra Turns on and then dies. New fuel pump, new filter, pressure to the rail, good spark and good injectors. The Supra runs when I spray either down throttle body and it also stays running with the afm flap opened with a screw driver. Might replace the afm 🤦🏻‍♂️.
 

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Yep, looks lije the AFM needs to ve opebed more than idle flow position to trigger the fuel pump.
OR,
you have significant air intake leak.
 
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Discussion Starter · #3 ·
Is there a way to adjust the afm. All vac lines are good checked them and intake after I replaced my injectors.
 

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Ditto to what J stated!! Check all your intake piping, vacuum lines off the intake piping and vacuum lines off the throttle body.
 

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My 86 Supra Turns on and then dies.
I assume that this means you keep your foot off the throttle when you turn the motor on. Then after it starts, it dies again with no throttle applied.
Does the same thing happen when you put your foot on the throttle after it starts?

I am asking because the ISC Idle Speed Control valve should adjust the idle speed if you have your foot off the pedal. If the throttle position sensor/throttle stop is misadjusted it will think you have your foot on the throttle and it will not try to adjust the idle speed. If you jazz the throttle will the engine stay running?

Dale
 

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Discussion Starter · #7 ·
I assume that this means you keep your foot off the throttle when you turn the motor on. Then after it starts, it dies again with no throttle applied.
Does the same thing happen when you put your foot on the throttle after it starts?

I am asking because the ISC Idle Speed Control valve should adjust the idle speed if you have your foot off the pedal. If the throttle position sensor/throttle stop is misadjusted it will think you have your foot on the throttle and it will not try to adjust the idle speed. If you jazz the throttle will the engine stay running?

Dale
[/QUOTE
 

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Discussion Starter · #8 ·
I’ll check right now, and Check again for vac leak because I just got my new AFM and same issue . 😩
 

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Discussion Starter · #9 ·
Got her going guys😎. It’s was a vac leak. The air intake tube has to be connected 🤦🏻‍♂️ 😂😂. My 85 camaro would at least run without the tube connected as long as the air mass sensor was connected, definitely not the case with the Supra. Had to do a few donuts to celebrate. 🏎 ☁☁☁☁🏁🏁🏁Now time to give the Supra a detail.🧐 💯
 

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Awesome job!!!(y)

Quick way to determine presence of vacuum-leak is:

  • measure AFM/MAF output voltage at idle (hold throttle open if necessary).
  • measure intake-manifold vacuum

Out-of-spec numbers will tell you to look closer for leak. In this case, it was big and obvious enough to kill car completely. But smaller leaks like single vacuum-hose can also cause random issues that can drive you crazy! That's when we break out the exhaust-plug , compressor, and soapy-water!
 

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The air intake tube has to be connected 🤦🏻‍♂️ 😂😂
That would do it for sure! 😁
We forget to mention that, because it is so obvious when you know where the components are on this engine.
 

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My 86 Supra Turns on and then dies. New fuel pump, new filter, pressure to the rail, good spark and good injectors. The Supra runs when I spray either down throttle body and it also stays running with the afm flap opened with a screw driver. Might replace the afm 🤦🏻‍♂️.
Try the iac valve. Mine had similar issues until I took it apart and cleaned all the carbon from the shaft. Lubricate and make sure it operates freely. Start the car and immediately shut it off and listen for a ticka, ticka, tick. If you do hear then it is functioning correctly. If no sound clean iac carefully. Don't bend the shaft.
 

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He fixed it, simply by installing all the parts! 😁
 
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