What controls vacuum to fuel regulator on 1994 isuzu pickup

All Isuzu vehicles in 1994 were shipped with a VACUUM ROUTING DIAGRAM sticker. permanentely affixed to the engine compartment of the vehicle. Vacuum routing varies from vehicle to vehicle because of variations in optional equipment, and the sticker shipped on the vehicle is essential, as there really is no "standard" vacuum routing.

You can get away with not having them, being a 94. But you won't get the best gas mileage it could have. Just make sure all the vacuum ports are blocked.

Fuel Pressure Regulator is located on the fuel rail.

1. Disconnect the negative battery cable.

2. Properly relieve the fuel system pressure.

3. Remove the air cleaner outlet tube(s).

4. Remove any necessary components to access the pressure regulator.

5. Disconnect the vacuum hose from the pressure regulator.

6. Remove the pressure regulator attaching screws.

7. Remove the pressure regulator from the fuel rail.

To Install

8. Discard the O-rings on the pressure regulator and replace them with new ones.

9. Lubricate the O-rings with clean engine oil.

10. Install the regulator into the fuel rail and tighten the retaining screws.

11. Connect the vacuum hose to the regulator.

12. Install any components removed to access the regulator.

13. Install the air cleaner outlet tube(s).

14. Connect the negative battery cable.

Did you pull the vacuum line off the regulator? When the regulator fails, you get more return flow and flow out the vacuum port into the engine.

the fuel pump is bad. you have a mechanical fuel pump which uses the engines oil. replace the pump

what do you mean ??notting???my advice is change all filters now.adrian,,,,

sounds like a bad fuel pump or fualty aftermarket pump/also i would check the fuel pressure regulator,and for any fuel leaks. if you disconect vacuum line from regulator and check to make sure fuel is not coming out of regulator and vacuum line is good if engine stays running most likely the fuel pump.

The fuel pump is mounted to the underside of the intake manifold where it bolts onto the cylinder head (real pain to get to). If you remove the fuel pump there is a plastic spacer between the pump and the manifold (DO NOT LOOSE IT).
Good luck
MIKESTA

might be a faulty air flow sensor

have you checked for vacuum leaks