No start...bad Oil pressure switch?

[Four-Four-Two]

Ok, heres my thread from the other day:

Here's the story:

I came outside afterwork yesterday and started my car. I forgot to clock out, so I was walking up to the door, and I heard my car die out. (Does that sometimes when its cold and I don't rev it at all) I clock out and come back to the car and try and start it, and it just cranks and cranks. I turned the key to "on" and heard the fuel pump turn on, so I checked the end of the fuel rail, and sure enough, no pressure. I pulled the end off of the fuel filter, turned the key on for a sec and turned it off, gas sprayed out(pressurized) So the pump works (3 week old Walbro 307), the fuel filter is brand new (put on the correct way). I also switched the 233 regulator for a known good 237. Still no fuel pressure. Tried starting a few times, but it just cranks and cranks.


Looking at this wiring diagram on GNttype.org, It looks like the relay closes the circuit to give power to the fuel pump. Once the car is running, and there is good oil pressure, the circuit opens and the current is directed through the Engine Oil Pressure Switch. The EOPS circuit closes, and the current runs through that to the pump.
Can I bypass the switch with a Posative wire to see if the switch is good or not?
Where is the switch, near the oil filter.

This sucks! I am only 17, so I don't know a whole lot about the workings of all the electrical crap in a car. My dad was a mechanic, but he got out of it before computers came into effect, so I'm on my own for the most part.

 

[WarpSpeed]

Welp, if you have fuel psi at the filter, you've got to have psi at the fuel rail,, unless the lines kinked(unlikely.)
I'd say something else happened, like a fuse blew, or the crank sensor went or something like that.

 

[MeanBuicks]

Here is a legible no-start diagnostic chart from the service manual.

 

[Steve Wood]

You misread the diagram. The relay stays closed...the oil pressure sender only closes after 4# of pressure and it serves as a back up in case the relay goes out. You can unplug the connector off the sender and the car will continue to start and run as long as the fuel pump relay is good.

Now, you have to find out why you have delivery at the filter but not at the rail. I guess the first question is what kinda volume/pressure are you seeing at the filter. If it is adequate, then the second question is what happened to it on the way to the fuel rail....two possibilites, the regulator is jammed open and will not allow pressure to build (and I would think that is not probable because you should still get good flow out the schraeder valv) or the hose at the front of the cross member has gone bad and closed off internally. I am speaking of the hose that makes the 90 deg turn at the front and connects the fuel line to the metal line going to the inlet side of the the rail.)

 

[Four-Four-Two]

I checked the voltage into the relay, it was 12.0. I then checked the voltage going into the pump, it was only 8. I have a PTE hotwire kit I haven't installed yet, would that help raise the voltage? Should I try and put it in?

Thanks for the help guys. I think I might just get the car towed to my school and have my auto teacher check it out.

 

[Steve Wood]

Put the kit on....you are losing at least 60% of the pump volume with that voltage. Whether or not it is the total problem, it is surely not helping you.

 

[REDS HOT AIR]

man if you got fuel to the filter than wireing has nothing to do with it.

loosen the line going in the filter after turning the key on to primre up and see that fuels sprays out .
then tighten it back up and turn the key on again to build pressure then loosen the line coming out the filter and see if you get sprayed again.

if not put another filter in it yours done collapsed.