Ok my 3.1's computer wasnt sending power to the fuel pump, ok, I solved that problem by manually sending power to it via a toggo switch. Once I get it started its all good, except it hasent learned idle yet. But my problem is when it starts up, it wont just crank and start like normal, I have to pump the gas to get her fired up, and ideas about fixing this. Someone said before it might be hy oil pressure switch, where is that located?

 

Its above the oil filter, on the housing. Pull the wire off of it and see if it's coated in oil. If it is, then yes, its dead. Head to Autozone and pick up one for $25 or so. Replace it (might as well change your oil & filter cause that's the easiest way to remove it, from the bottom) and you should be good.

 

k thanks, ill check it out, but it measures the pressure right, are we talking about the same sensor?

 

Yes, it's the same one, go to Autozone and ask for a new Oil Pressure Switch/Sensor and that will take care of your gauge and your FP switch (they combined them in I think 1987 & later cars)

 

Whoever told you the oil pressure switch could cause your car to be a pain to start is wrong. Very wrong. It's a backup circuit in case your fuel pump relay fails, not a kill switch.

 

Then what could be causing it? Oh and since my computer doesnt give the fuel pump power, should i have my jumper wire in before or after the relay? And yes the relay works

 

Have you checked your fuel pressure at all? Maybe you've got a leaky injector or two....so to start it like you said you have to give it pedal so it can try to burn off the excess.... Like in a carbed car, how if it floods out, you're supposed to start it with the gas pedal down to clear it out.

Not sure what proper fuel pressure is...but it should be one reading when the fuel pump is priming..when the pump has finished priming, the reading should vary. Not sure about yours since your pump is on a switch...I'd flip the switch and flip it back off after about 2 seconds or so and check pressure. Usually the non-priming pressure is, maybe, 5 psi lower than priming pressure. Also, the pressure shouldn't start to fall off very soon. If pressure starts falling off, that means there's a leak in the system somewhere, and could very well be leaky injectors like I mentioned.

 

ok, ill check that out, thanks

 

don't forget to check your cold start injector, it is located on the back of the manifold. if it is not hooked up correctly, you will have to pump gas to start the car.

doesn't the fuel pump get turned on from a signal in the ignition switch?

 

3.1's don't have a cold start injector...they did away with it.

 

Yep, the fuel pump gets turned on by the computer; and the computer gets turned on by the ignition switch (ECM IGN fuse). But, once oil pressure builds up to a certain pressure, the oil pressure switch gets turned on. If the pump relay melts, the oil pressure switch keeps the pump supplied with power.

You can verify this yourself; key off, unplug the fuel pump relay. Start the car- it'll take more cranking then usual, but it'll eventually start, as soon as oil pressure builds up.

Or, on 2.8's that didn't use the combination "single" oil pressure switch, just unplug the pump switch (two pin sensor at the oil filter), start the car, and go for a ride. if your fuel pump relay is okay, your engine will run great.

 

It wont work for me since my computer will not turn on the pump, and I even checked my relay, and the wire coming from the computer to the fuel pump relay.

Ok so the computer turns on the fuel pump by the egnition, so what would I all need to check for this?

Also my egnition cyl. is all messed up, because you have to jiggle it sometimes to get the key to turn.

 

You should have 12V all the time on the Orange wire at the fuel pump relay.

You should have 12V for 2 seconds when the key in turned to ON at the Dark Green/White wire at the fuel pump relay.

Start with these checks and pinpoint the problem. If you do have these voltages then you might have a problem on the ground side....or a bad PCM.

And just for kicks you can swap the relay with the A/C relay (they're the same) and see what happens.

 

done all that, and the relay works, where does the ground goto

 

Stupid question, but did you check for power at the fuel pump connector at the rear of the car? You might just have a bad fuel pump. Sometimes they can take a while to build pressure when they're bad.

The relay is grounded through the PCM and a body ground. Just follow the Black/White wire coming from the relay.

 

See, the oil pressure switch should be kicking the pump on. It'll bypass the computer and the fuel pump relay. After a few spins of the starter, oil pressure should build up enough to turn the pump on.

So it looks like both of those circuits are shot... ouch.

 

Yes the fuel pump is fine, because I can drive the car.

And when the car took a crap, I tried cranking and cranking on it, so that oil circut must be fried too, tomorrow im going to start checking the grounds, to see if maybe one of those are messed up.

Thanks guys, ill let you know what I come up with tomorrow