Had the problem with the fuel pump, check and re wired fuel pump, thought it was just lose wires in back.
still acted funny where it wouldn't come on unless I wacked the fuel pump area.

so I put in a new pump. still not coming on all the time. So must be the oil psi switch [fp relay never work or has work for 7+ years but ran fine but pump never primed until I had oil psi]
so n e ways, ordered new oil switch but its not here yet.

But I had wired a maual FP switch to run it for now.

but now I am having problems starting the car, unless it sits for a while. Just turns over n does nothing, if you shut it off and try to start it back up, shot of either and it starts right up n runs fine.

changed plugs, cap n rotor for kicks, thinking well maybe with the new FP its runnin rich.

well that didn't help. pulled some plugs and they are all nice and white and dry. not floodin.

so I start playing with wires and when I yank the plug off the oil psi switch, the motor dies.

looking at the wiring in the book, the FP relay and oil psi switch wiring runs into a big blank box and ya can't trace it any farther.

Not sure what I'm thinkin here but somehow the fp relay n oil switch are hooked into the cold start and injector circut?

why would the car stall when I pull the plug on the oil psi switch when the FP is wire hot with a manual switch?

Only thing I can think of is, somhow removing that plug, killed power to the injectors. which might be only working cause of my hot wired manual switch on the FP.

or is the fp n oil swtich somehow connector to the ign?

I got the book of wiring but its not 100% clear, all the wires just run to a big blank box and ya can't trace them any farther.

wish they just listed the full wiring diagram, instead of chopping it all up.

 

Even more confused cause I confirmed my symptoms.

with the plug yanked off the oil psi switch, the motor does not get fuel. It will fire on either and diesel but will not start. hook up oil psi switch and it will start. yank the plug, and the motor dies.

the FP is wired hot at the tank, on the tan wire. So it bypasses the whole wiring system, but I guess something else is bad, and its reverse charging the system, making it work. but??/???

I'm so confused on this one. none of it makes any sense.

 

the oil switch connects directly to the Fuel pump as a engine saving measure so that if the car has no oil pressure it will not run. this is supposed to prevent you from running it dry of oil. so you disconnect it and it and the Fuel pump will turn off.

 

OK it was all my fault, the system was being reversed charged and it didn't like it.

maybe it was the extra ground wire, I dunno. power wire is switch so it can't **** it off all the time. But once I clipped my manual wires for the fuel pump, everything was fine. oil switch works..... car start up no problem once shut off.

it all started like bad wiring and I hate getting stuck like that, so the manual switch was my back up fix but the computer does not like it. and was of course the FP all along but the way things acted lead me down this road.

oh well, tunes up are good anytime, weather you need it or not.

I can use the oil switch for my buick.

last 2 days of hair pulling just means it don't need cut for a while.

oh and to clear it up, the FP fuse is on the left fender well, facing the front of the car. Looks like a weather pack plug but has a normal fuse in it. orange n red wire run to it.

 

This is wrong.

 

well i can go start my car and it will shut off if i unplug that switch. how do i know? well i was checking for exhaust leaks and i hit the wires to it. it mush not have been on very well cause i poped off and the car shut off. when its not pluged in my FP wont turn on but if i plug it back in it works perfectly.

 

Then your FP relay (or related wiring to/from) is bad... it's not a low oil pressure cutoff though.

Not on a iron duke, v-6 or v-8

The oil pressure switch is wired in parallel with the pump wiring. It is a bypass for the FP relay in the even the relay fails. Keeps you from getting stranded.

The ecm does not know or even care if the switch is even presesnt.

I'm probably just as wrong about this as the runner though .huh ?

 

confusing part was the main fuse for the pump line was blown.
but was still being charged in reverse via my manual switch. When oil switch was unplugged, the fuel pump n line still had power.

unhookin the oil swtich killed the spark some how?

but n e ways, the car did not like it. very weak spark with hard to needin either to start.

clipped manual wire, new fues and all is well.

 

Oh thats why it used to not start till i had cranked the engine for a bit. i replaced all the Relays in the car cause the PO had pulled them apart ruining the seal and it began starrting the second i hit the switch. At least from what you said that sounds like the esplanation. whatever the cause i dont care the car runs great all the same.

Runner? what ya mean?

Edit: oh i did had not messed with one of those before so i didnt think it had a different lower section from a 2.8l or 3.1l. I apologize for arguing with ya bout that. kinda makes since tho that if they didnt change the lower intake manifold they must have added something other than extra runner so that it would not fit a Dist.