[Bo185]

TBI is like 9-10psi The 454 unit is higher 26-32ish.

There is also a vaccum ref unit you can swap on too. But you can just replace the your regulator. One for a SBC is ACDELCO 2172903 $40 on RA. Several of videos on how to change as well on the yourtubes.

 

[Bo185]

Yeah, the TPI pumps were regulated around 45 psi. My buddies should still be running stock TBI fuel pressure unless that regulator has failed... i just wasnt sure that if the regulator has failed closed if the pressure itself could cause the injectors to blow open like that. In fact, im fairly sure that the fuel pump shouldnt even be running if the ECM isnt seeing a crank signal.

Remove the return. If zero fuel is coming out at all then reg bad. If return line is plug it will causes issues as well. The pump will prime for 5-7 seconds at first turn of key. So if you turn it off and back on it will run. Once it sees ign it turns on all time. I can't remember if the TBI injectors will blow open under pressure they may not. But they may be streaking or stuck open with trash as well, now if the reg is bad that will increase pressure they see as well so they will flow more through them too over fueling, hence replace reg. as its easy to do.