recently I tested my fuel pressure and got 65 psi. Now when I say I got 65 psi, that was with and without the vacuum line connected to the reg, and with key on engine off and running. Is this normal or is the reg/damper (as some call it) bad? When I throttled it up, I only had a slight drop in psi (maybe half or full pound) for a split second then back to 65.

Also I replaced my vacuum lines because of a small leak at the one dual connection, but haven't retested it since (don't recall if one of the lines from the dual connection was from the reg).

 

I'm sure someone could help if you mentioned the year and model. I seem to remember 40-45 psi being the correct value for my 4.0 Ranger and Aerostar, but all the stuff I drive is old. I would expect the pressure to change with and without the vacuum line hooked up, though.

 

its a 2000 exploder 4.0 ohv

 

Per the factory service manual, the fuel pressure spec for a 2000 Explorer (regardless of engine) is 65 +/- 8 PSI. The same pressure applies for KOEO and KOER.

-Rod

 

thanks, the only other thing is does it matter if the vacuum line is connected to the I guess damper, the piece on the fuel rail. because when I tested I got 65 with and without the vacuum line attached, and maybe a 1 lb drop for a split second when throttled up each way also (which I'm not worried about with that small of a drop, could barely see the needle move hince the maybe 1 lb)

 

The mechanical fuel pressure regulator is there to relieve over pressure. If the system is not going over pressure (which your readings would indicate it is not) you won't notice a difference with the regulator connected to vacuum or not.

-Rod