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UZ-FE Vapor Lock

randeyc

New Member
I have a1UZ in a hot rod. it has been runnign and driving great. This morning start it up running fine start to drive and engine dies. Turns over wants to start, and dies. Clearly a fuel problem I seems like a vapor lock. fuel tank has a clear vent, fuel filter is clean and clear. initially no return of fuel to tank. Break open all the fittings in the line and then get return to the tank. Started and runs great. Let it sit a few hours and the problem starts again.

Any Ideas? Thank for the help.
 

cribbj

"Supra" Moderator
Staff member
Also check your fuel pump:

1. Make sure it's developing the pressure at the rail

2. And the pressure isn't bleeding down as soon as you turn the engine off
 

Zuffen

Super Moderator
Staff member
Is your fuel pump below the level of fuel int he tank.

If you're asking an EFI pump to lift the fuel before pumping it expect problems.

Sounds to me like the fuel pump is developing an air lock due to the fuel draining back out of the pump which would mean it's trying to pump air. EFI pumps don't like pumping air and self primeing.
 

randeyc

New Member
update

New fuel pump in, cleared to computer. Engine started right up ran 2-3 minutes and died, same symptoms. Clear computer starts, runs 2-3 min and dies. It must be a sensor. Now the question is which one.
 

cribbj

"Supra" Moderator
Staff member
I seem to recall that a faulty crank or cam sensor will allow the engine to start, but not run for longer than a few seconds (not minutes, seconds).

So, are you getting good fuel pressure and is it holding after you shutoff?
 
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