1997 Pontiac Firebird Fuel injection pressure bleed / leak

RN1944

MEMBER
1997 PONTIAC FIREBIRD
6 CYL
2WD
AUTOMATIC
142,000 MILES

Here goes - all parts new from fuel pump out to engine. 12 volts back at pump, and 10psi. Out at engine. Engine runs well (pressure goes way up when running - say 40psi), but when sitting (even with new injectors, fuel pressure regulator, filter, plugs) fuel pressure up at injectors is somehow leaking down - this is even with the new "fuel pressure regulator". Is there any other way besides the pressure regulator holding pressure up to the rails, and injectors that would let the fuel possibly bleed / leak back down to gas tank thru fuel return line?

2 Replies

BLUELIGHTNIN6

MECHANIC
16,542 POSTS

Hello and thanks for donating

The pressure leak is either inside the manifold or going back into the tank (if we assume it isn't leaking out onto the floor) To differentiate between the two, repeatedly turn key on every so often for an hour or so. After this start vehicle as normal and if the leak is inside manifold then the car will start very rich, and have black smoke coming out of pipe. If it still starts normal then the leak can be assumed to be going back to fuel tank and is pump or regulator perhaps allowing it to return thru the return line or even a leaky hose at the fuel pump itself.