Relieving fuel system pressure is obviously an important prerequisite to many repairs and maintenance tasks. However, it seems as if there are a variety of recommendations to relieve the fuel pressure. Perhaps the two most common methods, at least for fuel injected systems, are pulling the fuel pump relay and bleeding at the Schrader or similar valve.
Ordinarily, I might assume that the appropriate approaches varies with the vehicle. While this still might be true, for the same vehicle (a 1996 Chevy G10/Express van), my Chilton's and Haynes manual each recommended a different method (the relay approach vs bleeding as the valve).
Personally, when I changed the fuel filter on the van, I pulled the relay, started it, and let it die (as recommended by the manual I had at the time). When I pulled the filter, it seemed as if quite a bit more fuel sprayed than I was accustomed to (this was not my first time changing a fuel filter, but my previous vehicle was a TBI). I am wondering if using a bleeder valve would have perhaps done a better job.
As such, I have the a couple questions:
- Is there any universal (or nearly universal) method for safely and effectively relieving the fuel pressure on any given fuel-injected vehicle, or will this vary extensively? If not, what determines the appropriate method; for example, is it the form of fuel injection used (CSFI, MPFI, etc)?
- In general, is either pulling the relay or bleeding the line more effective?