: Fuel In Intake Manifold

12-13-04, 03:33 PM
1993 Cadillac Northstar 4.6 R&r Starter Pulled Top Cover, Fixed Starter Problem. Now Have Bad Fuel Leak, All The Injectors,seals Looked Good. Is Their Any Seal,oring In The Inlet,return Lines? The Hoses Looked Good Between The Injectors.thanks 4 Any Help.it Will Start If You Hold Throttel Wide Open Running Very Rich.

12-14-04, 10:43 AM
Take the cover off and turn the key on to pressurise the fuel system. DO NOT START THE ENGINE with the cover off as it will run unthrottled (WOT). Look for a leaking FPR or leak in the fuel line. If no leaks are found, perhaps a stuck open injector(s).

12-14-04, 02:45 PM
Well...you didn't need to pull the top cover to change the starter... Just take out the center four bolts that are recessed into the top cover and the entire intake will come off in one piece.

Likely you disturbed the fuel return/fuel pressure regulator fitting when the top cover was off ESPECIALLY if you levered the intake out of the way with the top cover off. The fuel pressure regulator and fuel return line seals to the enclosure with an o-ring seal of sorts that relies on the compression of the top cover being in place to hold it down and in position. If you stressed the fuel return line at all with the top cover off the connection cut or mislocated the o-ring seal. Take out the perimeter row of screws holding the top cover down and inspect the fuel pressure regulator area. You'll likely see the leak that is internal to the manifold caused by disloding the fuel pressure regulator during the repair.

I would grab a new FPR and just replace it when you are in there as the FPR is sort of a 100K/10 year item that is almost part of a "tune up" on those. If it is not leaking internally now it will probably start soon anyway.

If you take the top cover off turn the key to on (do NOT start or crank...just turn to the on position) to energize the fuel pump and pressurize the fuel system and you will quickly see the leak source. Fuel is likely to spray when you do this so be ready and have no ignition sources nearby and have a fire extenguisher handy just in case.....